Thesis.Phase III A comparison of Festulolium cultivars and parental grasses for the reclamation...

Phase III: A comparison of Festulolium cultivars and parental

grasses for the reclamation of soil forming materials associated

with opencast coal mining

By

Mr John Richard Gibson

Submitted in part candidature for the degree of M.Sc., Institute of Biological,

Environmental and Rural Sciences, Aberystwyth University

2015

1

DECLARATION

This work has not previously been accepted in substance for any degree and is not being

concurrently submitted in candidature for any degree.

Signed

...................................................................... (candidate)

Date ........................................................................

STATEMENT 1

This work is the result of my own investigations, except where otherwise stated.

Where *correction services have been used, the extent and nature of the correction is

clearly marked in a footnote(s).

Other sources are acknowledged (e.g. by footnotes giving explicit references).

A bibliography is appended.

Signed

..................................................................... (candidate)

Date ........................................................................

[*this refers to the extent to which the text has been corrected by others]

2

STATEMENT 2

I hereby give consent for my work, if accepted, to be available for photocopying and for

inter-library loan, and for the title and summary to be made available to outside

organisations.

Signed .............................................................. (candidate)

Date ........................................................................

NB:

Candidates on whose behalf a bar on access has been approved by the University,

should use the following version of Statement 2:

I hereby give consent for my work, if accepted, to be available for photocopying and for

inter-library loans after expiry of a bar on access approved by Aberystwyth University.

Signed ............................................................... (candidate)

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3

ACKNOWLEDGEMENTS

This work is part-funded by the European Social Fund (ESF) through the European Union’s

Convergence programme administered by the Welsh Government.

This dissertation would not have been possible without crucial help from particular individuals.

Firstly, I would like to thank the direct support through John Scullion and his guidance

throughout. Secondly, I would like to highlight what a major part my dyslexia tutor, Alison Nash,

has had with this work and throughout my university education. Without Alison, I would have

truly struggled with academia and she has given me the tools to develop as an individual and as

a post graduate.

Throughout this dissertation there has been help from very kind individuals. Georgina Taubman

at Miller Argent has provided me with exceptional help. Georgina has been key with the

arrangements of site visits and additional help with numerous queries. Andrew Detheridge has

also been a pillar of support throughout all the Laboratory experiments and I would personally

like to thank him for his genuine kindness.

I would also like to take this opportunity to thank my family, friends and partner Rebecca Bryne,

for all their support with academia and this dissertation, which seemed a little less daunting with

your help.

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ABSTRACT

Coal extraction from opencast mining can cause considerable degradation to

landscapes, including the eradication of vegetation and severe damage to the soil

system’s physical, biological and chemical composition. Public and governmental

heightened awareness of environmental sensitivity and increasing demand for land in

the UK has increased pressures to restore land post-mining. This study investigated the

potential of cultivars as part of a grassland for reclamation of the opencast mine site at

Ffos-y-fran in South Wales. Research included the hybrid Festuloliums, (LpFg, LpFg2,

LpFm and Prior) and parental cultivars, (Ryegrasses - Aber Dart, Aber Magic and Fescues

- Bn1482 and Bf1317), upon four available restoration materials, (Soil forming material,

Weathered shale, Overburden shale and Boulder clay). The Festulolium cultivars

combine the benefical traits of Ryegrasses and Fescue parental species to potentially

create cultivars with enhanced productivity and tolerance amongst challenging abiotic

and biotic conditions on site. This study has collected data from the experimental plots

within its third year after establishment and analysed the above and below ground

development of all cultivars. Overall, the Fescue Bn1482 consistently produced the

greater herbage yields and percentage ground cover compared to all other cultivars in

the third year. The cultivar also produced a highly significant (P<0.001) greater

cumulative herbage yield for this growing period. This was contrary to previous findings

from the plots in their second year which concluded that Festuloliums created

significantly greater yield and ground cover within initial establishment. Bn1482 also

produced significantly greater (P<0.05) root mass within near surface topsoil, bar LpFg

and initial distribution trends have suggested Bn1482 has replicated this development

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at depth as well. However, this is not conclusive and there is no previous fully replicated

root data for comparison. The soil forming material available on site consistently aided

the cultivar’s above ground development throughout the three year study on the Ffos-

y-fran site. Investigations were undertaken into soil organic matter and microbial

activity, but these were inconclusive due to site specifics and inappropriate analytical

methods. At this stage of investigations, the Festuloliums and Fescue Bn1482 have

provided evidence that they could contribute to erosion mitigation and soil

rehabilitation, potentially as a mixed sward, for this reclamation project with the

utilisation of the soil forming material.

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CONTENTS

DECLARATION ............................................................................................................................. 1

ACKNOWLEDGEMENTS.............................................................................................................. 3

ABSTRACT .................................................................................................................................... 4

ABBREVIATIONS .......................................................................................................................... 9

LIST OF FIGURES ....................................................................................................................... 10

LIST OF TABLES .......................................................................................................................... 12

1.LITERATURE REVIEW ............................................................................................................. 13

1.1 Introduction to reclamation ............................................................................. 13

1.2 Consequences of mining wasteland without restoration ................................ 14

1.3 Restoration and reclamation definition ........................................................... 15

1.4 Issues affecting reclamation efforts ................................................................. 16

1.5 Treatments ....................................................................................................... 18

1.6 The use of vegetation within reclamation projects ......................................... 20

1.7 Other benefits of using vegetation as a reclamation tool............................... 22

1.8 Grassland beneficial use within reclamation projects ..................................... 22

1.9 Grass species used within the commercial sector and reclamation projects .. 24

1.9.1 Perrenial Ryegrasss Lolium perenne ......................................................... 24

1.9.2 Fescue Fustuca .......................................................................................... 25

1.10 The breeding of grasses in the UK .................................................................... 25

1.11 Recent development of Festulloliums and potential benefits for reclamation

projects ........................................................................................................................ 25

1.11.1 Festuloliums potential to provide environmental services ...................... 26

1.11.2 Festuloliums commercial potential ........................................................... 27

1.11.3 Festulolium potential as a reclamtion tool ............................................... 28

1.12 Why would microbial activity be crucial for reclamation sites? ...................... 30

1.13 Gaps in Knowledge ........................................................................................... 32

1.14 Hypotheses ....................................................................................................... 35

2.METHODOLOGY .................................................................................................................... 36

2.1 Study site .......................................................................................................... 36

2.2 Miller Argents reclamation aim ........................................................................ 37

2.3 Climate ............................................................................................................. 38

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2.4 Geology ........................................................................................................... 40

2.5 Soil properties .................................................................................................. 40

2.6 The field experiment ........................................................................................ 41

2.6.1 Experimental plot design .......................................................................... 41

2.6.2 Grass species and plot layout.................................................................... 41

2.6.3 Grass species chosen ................................................................................. 43

2.6.4 Applied fertiliser ........................................................................................ 45

2.6.5 Herbage collection .................................................................................... 46

2.6.6 Ground cover assessment ......................................................................... 46

2.6.7 Soil cores ................................................................................................... 47

2.6.8 Deep rooting distribution assessment ...................................................... 47

2.7 Laboratory investigations ................................................................................. 49

2.7.1 Root biomass ............................................................................................. 49

2.7.2 Herbage dry matter ................................................................................... 49

2.7.3 Soil organic matter (SOM) ......................................................................... 50

2.7.4 Soil respiration assessment ....................................................................... 50

2.8 Statistical analyses ............................................................................................ 51

3.RESULTS .................................................................................................................................. 53

3.1 Herbage analyses .............................................................................................. 58

3.1.1 Cut One...................................................................................................... 58

3.1.2 Cut Two ..................................................................................................... 58

3.1.3 Cut Three ................................................................................................... 59

3.1.4 Cut Four ..................................................................................................... 62

3.1.5 Cut Five ...................................................................................................... 63

3.1.6 Total Herbage ............................................................................................ 65

3.2 Percentage coverage .......................................................................................... 69

3.3 Soil Organic Matter (SOM) .................................................................................. 74

3.3.1 Loss of Ignition at 300 oC analyses results ................................................... 74

3.3.2 Loss of Ignition at 400 oC analyses .............................................................. 75

3.4 Respiration .......................................................................................................... 75

3.4.1 Natural state sample CO2 analyses .............................................................. 75

3.4.2 Optimised moisture samples CO2 analyses ................................................. 76

3.5 Root mass ........................................................................................................... 77

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3.6 Root distribution ................................................................................................. 79

4.DISCUSSION ........................................................................................................................... 81

4.1 Festulolium cultivars will create greater herbage yield and ground coverage

compared to their parental species. ........................................................................... 81

4.2 Festulolium cultivars will have a greater root development within material

compared with their parental species. ....................................................................... 86

4.3 Festulolium cultivars will create greater SOM and an enhanced microbial activity

..................................................................................................................................... 92

4.4 Materials will differ in their potential for reclamation objectives ...................... 95

5. CONCLUSION......................................................................................................................... 98

5.1 Recommendations .......................................................................................... 100

5.2 Future Research .............................................................................................. 101

6. REFERENCE LIST………………………………………………………………………………………………103

7. APPENDIX (For appendix see disc)

7.1 Subplot designs

7.2 Raw Data

7.3 Two Way ANOVA Results

7.4 ANOVA Results

7.5 Kruskal –Wallis Test Results

7.6 Post Hoc, Tukey Results

7.7 Descriptives

7.8 Log 10 Data

7.9 Levenes Results

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ABBREVIATIONS

ANOVA Analysis of Variance

CO2 Carbon Dioxide

CV Cultivar

DMY Dry Matter Yield

G Gram

G/M2 Grams Per Metre Squared

HSG High Sugar Grass

IBERS Institute of Biology, Environmental and Rural Studies

KW Kruskal-Wallis test

PPM Parts Per Million

SD Standard Deviations

SOC Soil Organic Carbon

SOM Soil Organic Matter

Spp Species

TWA Two Way ANOVA

Var Variety

WLOI Weight lost on Ignition

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LIST OF FIGURES

Figure 1. Location of the Miller Argent site ..................................................................... 37

Figure 2. Aerial photograph of the Miller Argent site at Merthyr Tydfil. The photograph

was taken prior to the extraction of coal, part of the third phase of extraction. ............ 38

Figure 3. Weather data collected from Miller Argent weather station, displaying climatic

variations and individual field experiments and applications of fertiliser. ...................... 39

Figure 4.Experimental plot layout and illustration of subplot divides. ............................ 42

Figure 5. Illustration of the root distribution analyses and typical soil pit face which was

excavated alongside subplots on the circumference of the plot. .................................... 48

Figure 6. Total mean herbage (dry weight) collected from each group of grass cultivars

from cut two.. .................................................................................................................. 59


from cut three.. ............................................................................................................... 60

Figure 8. Total mean herbage (dry weight) collected from each group soil material from

cut three. ......................................................................................................................... 61

Figure 9.Total mean herbage (dry weight) collected from each group soil material from

cut four. ........................................................................................................................... 63

Figure 10. Total mean herbage (dry weight) collected from each group over all four

materials during cut five. ................................................................................................. 64


over all four soil materials.. ............................................................................................. 66


from the soil forming material......................................................................................... 67


from the overburden material.. ....................................................................................... 68

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Figure 14. Cultivars’ mean root mass weights and their percentage quantity of the20g

soil sample, representing all the materials.. .................................................................... 78

Figure 15.Cluster bars show the absolute counts of roots and the split of these

between the shallow and depth counts. ........................................................................ 80

Figure 16.Evidence of Bn1482 enhanced herbage and ground cover and the established

ground cover of festuloliums. The photographs were taken on the final cut in August on

the best performing material, soil forming material.. ..................................................... 83

Figure 17. The distribution of the roots of Bn1482 , LpFm and LpFm , on the soil forming

material. .......................................................................................................................... 90

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LIST OF TABLES

Table 1.Statistical analyses procedure for each individual investigation.. ................................... 56

Table 2. Cultivars mean totals from each investigation. This data is the raw mean values which

was collected from the field subplots and the laboratory experiments. ..................................... 70

Table 3.Material mean totals from each investigation. This data is the raw mean values which

was collected from the field subplots and the laboratory experiments. ..................................... 72

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1. LITERATURE REVIEW

Throughout the history of man, land has been crucial for our existence and an

irreplaceable vital resource. The extraction and utilisation of Fossil-fuels and mineral

resources has recently escalated. Expansion of industrial areas, economic

developments, technological improvements and rapid growth of worldwide human

population, coupled with urbanisation, have driven this demand (Kundu & Ghose, 1997)

and installed a reliance upon them (Sheoran et al., 2010).

1.1 Introduction to reclamation

Mining has been integral to the Welsh economy throughout the nineteenth and early

part of the twentieth century, although the industry has reduced production due to a

competitive global market and financial cost of extraction through deep mining methods

(Haigh, 1992). Recently opencast mining for coal has become more prevalent

throughout Europe, due to increasing costs of importing coal and it is more economically

viable where coal seams are near to the surface (World Coal Association, 2012). This

investigation will be located at the Miller Argent site at Merthyr Tydfil, which uses this

opencast mining technique to extract coal. The coal is relatively close to the surface and

is accessible for extraction by creating large open pits and then removing the surface

material (European Commission, 2015).This process causes a magnitude of destruction

and degradation to on site soil, flora and fauna. Restoring mining wastelands can be

problematic, especially as the mining activities severely disfigure the aesthetic

landscape and disorder the pre-existing ecosystem, including the naturally occurring

vegetation, nutrient cycles, soil profiles, and microbial communities (Kundu & Ghose,

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1997). Historically, the development of civilisation has seen an increase in degraded sites

due to mining operations (Bradshaw, 1983).

Regular poor husbandry of these mining sites, post extraction, has developed an

increasing emphasis for the mining industry to adopt environmentally sensitive

strategies and greater reclamation efforts (Mason & Milbourne, 2013).The

improvement to reclamation projects and public awareness of this has been crucial to

combat the increasing intolerance within society to neighbouring mining operations,

due to historic legacies of degraded land and pollution originating from these sites

(Haigh, 1993).

1.2 Consequences of mining wasteland without restoration

The process of extracting coal can disfigure landscapes, alter soil aggregation and can

further degrade soils that have potential for restoration through the removal process

and long term stockpiling. All of these detrimental processes can consequently

negatively change the site’s hydrology, nutrient availability and soil dispersal (Six et al.,

2004).

The permanent transformation of the landscape and eradication of vegetation on mine

lands consequently means surrounding environments are also threatened by an

increased runoff and erosion of soil from the site (Zhao et al., 2013). Exacerbated runoff

collects important restoration material such as fine material and nutrients, amplifying

erosion and impeding the reclamation process (Polyakv and Lal, 2004). Local climatic

conditions (e.g rainfall), soil properties and the landscape’s characteristics all contribute

to the degree of erosion and runoff. These detrimental effects crucially hamper

vegetation recovery, which means the effects can proliferate, exacerbating

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environmental degradation to the site and threatening the surrounding landscape

(Zhang et al., 2015). For this reason, it is widely covered in the literature that re-

vegetating mine wasteland is fundamental for long term stable ecological restoration

and reclamation projects (Bao et al., 2012; Drazic et al., 2012).

Sedimentation is a real issue due to the collection of soil sediment from runoff, creating

gullying effects to the land, especially if the land is left bare (Sengupta, 1993). This is a

concern in Wales, where climatic conditions include periods of prolonged, frequent and

heavy rainfall (Met Office, 2015).Erosion mitigation can include re-angling slopes by

grading/ terracing, sediment traps and re-vegetation of exposed slopes.

Another issue with runoff is the chemical quality. Water that has been in contact with

coal typically contains a moderate to high level of sulphur. Also, the exposure of pyrite

in the material to air and water can lead to oxidation, resulting in acidity issues within

the collected water .This is a common problem of coal mines and the corrosive water

has great potential to affect neighbouring aquatic life, and is generally known as acid

mine drainage (Sengupta, 1993).

1.3 Restoration and reclamation definition

The coal mining industry was privatised in 1994, which allows private companys to

extract coal with restrictions set by the government. However, companies are bound by

legal obligations and guidelines to consider the surrounding environments, local

hertiage and communities (IEA, 2013). Assessments such as “Environmental Impact

Assessments” need to be obtained to assess the degree of impact that the mining

operation will have on the site and surrounding areas. These typically include mitigation

procedures (i.e detailed reclamation projects), which are assessed by the local council

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or central governments, whether the mitigation is sufficient to limit the impact to an

acceptable level. Planning consent to extract the coal then can be given to the minning

company (DCLG, 2015). Sometimes, mining bonds are set aside for future restoration

needs, post mining extraction, so that minimal environmental standards are achieved

(IEA, 2013). The ambiguous definition of restoration is therefore crucial a problem.

Ecological restoration has no one definition and is broadly seen as the method of aiding

the recovery of the land’s ecosystem (SER, 2015). Literature suggests that “restoration”

implies that rehabilitation should include the structure and functions of an ecosystem

to the exact quality of the pre-mining ecosystem (Bradshaw, 2000). Whereas,

“Reclamation” is the typically used terminology and method, which refers to the process

which aims to restore the land into a beneficial use and meets the minimal standards

required (Cooke & Johnson, 2002). Consequently, land is restored typically for

conservation or commercial use and incorporates measures to limit the site’s effects on

the surounding environment, due to legal protection of surrounding watercourses and

‘polluter pays’ law principles (IEA, 2013). However, typically rehabilitating land into a

productive state, including some biotic function or productivity, means such targets are

limited by site-specific issues or biota. Plant growth is generally crucial to create a

sustainable nutrient cycle and microbial activity (Brown & Lugo, 1994).

1.4 Issues affecting reclamation efforts

A common fundamental problem for reclamation projects is that material is frequently

vastly biologically and physically different to the site’s original soil (Bradshaw , 1997).

Tate et al., (1987) explained that the success of reclamation of Lignite wasteland sites in

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the USA, especially when topsoil was absent, was highly depending on the rapid creation

of surface soil horizons containing large volumes of soil organic matter. Unfortunately,

replacing topsoil and recreating effective horizons is often costly in the UK, so less

favourable material which is abundant on site is frequently utilised with limited horizons

(Bradshaw, 2000). Without effective mitigation, the residual material is incapable of

supporting rapid regrowth due to undeveloped soil systems and a limited seed bank

(Wick & Daniels, 2009; Piha et al, 1995). Evidence suggests sites can self-regenerate

through colonisation and succession, but this can take 100 years and is reliant on soil

material. However, surrounding environments are left vulnerable during this period and

due to UK demand for land, this has not been a feasible option (Bradshaw, 2000).

Moreover, the stockpiling of available valuable loose material, prior to extraction, is

subject to degradation due to stripping operations, anerobic storage conditions and

pressure related issues (Li, 2006).

In mined areas of South Wales, friable shale is regularly utilised for reclamation, when

there is no available topsoil and mining has extracted deep mine spoils. However when

exposed to the surrounding environment or severely disturbed it is liable to erode

through weathering. Clay particles can be released from the breakdown of the shale,

which then will display similar traits of clay substrates and have a direct impact on the

soil’s quality due to the soil pores becoming congested. Water filtration throughout the

material, like clay, is therefore impeded which can consequently create greater soil

density, waterlogging, hamper vegetation development, increase mortality of soil

microbiota and reduce the soil’s cumulative stability (Haigh, 1992; Ibarra & Moreno de

las Heras, 2004).

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Overburden, is commonly the most abundant material on site, post mining, but again

this is not a natural substrate for vegetation establishment. Overburden is the material

above coal that needs to be removed to access the coal. Shale and overburden, both

coming from depths and from raw rock, are always deficient in nitrogen. This material

is also characterised with having typically no or unavailable forms of phosphate, calcium

and /or potassium (Coppin and Bradshaw, 1982).

Maiti and Ghose (2005) investigated the rock content of Welsh overburden on coal

wastelands, concluding that the material comprises on average 55% by mass of particles

greater than the ideal 2mm. This causes an issue with retention of water and nutients

(Nicolau, 2002).

In the absence of topsoil, soil-forming materials can be created from a mixture of onsite

quarred geological and overburden materials plus other refined minerals or organic

substances. The emphasis in this procedure, is to create an effective material base to

support the needs of vegetetation growth and form a base to start the soil forming

process (Forestry Commission, 2002).This provides reclamation projects with an

alternative to overburden and shales

1.5 Treatments

Applications of nitrogen rich fertiliser are common practice, prompting rapid plant

regrowth, but without a natural nutrient cycle then the system is heavily reliant on

repeat applications and therefore is not sustainable. Vegetation such as legumes can be

added to aid nitrogen fixation but applications of phosphorus are needed to maintain

early growth (Bradshaw, 1989). Longhurst & Connor, (1999) researched on vegetation

establishment on coal reclamation sites and stated that nitrogen and phosphorus are

19

both limiting factors, especially during the initial two years. Moreover, the literature

suggests that phosphate is crucial, especially with early growth and root development

within difficult materials (McQueen & Ross, 1982; Hart & August, 1988). Previous studies

into application of fertiliser on reclamation sites in New Zealand have found that varying

volumes of applied fertiliser positively correlated with increased yield. Furthermore, the

vegetation communities changed throughout time, with ryegrass establishing quickly on

materials and fescue species generally developing slower, but becoming more dominant

(Roberts et al., 1988).

One major source of these nutrients is organic matter, hence typically application of this

is required and objectives to improve the ecosystem should include provision to provide

this naturally (Danahoe et al., 1990). Gosh et al. (1983) suggested that organic carbon

within the soils is a good indicator of fertile and healthy soils. Therefore habitats that

can sustain soil organic matter (SOM) through a sustainable carbon cycle, have potential

to create a healthy soil system (Roberts et al., 1988).

The operations of strip mining using heavy machinery, stockpiling and spreading of

material can exacerbate the detrimental effects of compaction, leading to increased

runoff and surface erosion (Thompson et al., 1987). This is because the compacted

material severely limits the ground capacity to absorb the rainfall (Haigh &

Sansom,1999). Compacted land suffers from reduced soil pores and water-stable soil

aggregates. The reduced water infiltration capability and the added density restrict the

root penetrating potential to access water and nutrients (Gerrard, 2003). For these

reasons and the altered soil structure, compacted land does not favour vegetation

growth and restricts soil organisms (Haigh, 2000; Gunwald et al., 1988). Moreover,

20

compacted soils can limit the capacity of organisms within soil systems to respire, which

is liable to create an accumulation of toxic CO2 which directly affects roots and the ability

of micro-organisms to access oxygen (Osman, 2013). However, studies by Keislinga et

al., (1995) concluded that some plant species are capable of adapting their root

behaviour and morphology (reducing biomass, size and increasing distribution) to

combat compacted conditions. Modern mining practices such as ripping have alleviated

compaction caused by activities, but some compaction is generally unavoidable

(Sheoran et al., 2010).

1.6 The use of vegetation within reclamation projects

Plant growth has an essential role in the reclamation process as it directly protects from

surface soil erosion and retains fine soil particles needed for soil development. Multiple

benefits include decreasing the soil density, stabilising the pH and playing an active role

in circulating mineral nutrients and transforming them into a useable form (Bradshaw,

1997). Plants can improve physical soil properties directly (soil density, water retention

and porosity) and its structure, which directly affects filtration, stabilisation and the

availability of gases, nutrients and water (Zhang et al., 2015).

Vegetational growth is highly reliant on the plants ability to access nutrients and water.

Roots are essential to explore soils and they do this by elongating through and

displacing, soil particles. Compaction can inhibit root elongation rate due to the energy

required to overcome the soil particle’s resistance and reduced aeration, although

contact between root and soil is increased (Clark et al., 2003).

Drought conditions can futher challenge the potential for roots to penetrate material,

as soils/ material can become stronger as water content reduces (Whiteley & Dexter,

21

1982). Plants have adapted their roots to their surrounding soil to maximise their ability

to obtain nutrients and penetrate soil. Studies by Whalley et al., (2005) have shown that

roots of plants can also alter water movements within soils due to creating greater soil

pores within rhizosphere areas or altering repellence.

However, roots can become sensitive to rapid changes to their surrounding

environment, including soil properties, and plant species will have varying capabilities

to cope under these pressures (Russell et al., 2013). Plant have adapted their roots to

their insitu soils by developing their own biochemicial mechanisims which create

numerous unique soil-plant systems within indigineous environments (Kabata-Pendias,

2004). It is generally unclear in the literature how plant species will react to site-specific

alterations to soil properties, especially if the material is not typical of natural top/sub

soil material.

Studies by Scholefield and Hall (1985) discovered that Ryegrass root growth was

restricted by their cap & stele diameter . Numerous other studies have found that plant

species can be capable of growing their roots into pores which are smaller than their

root diameter (Bengough & McKenzie, 1997; Scholefield & Hall, 1985). The ability of

plants to penetrate throughout the soil correlates typcially with their ability to access

water and nutrients needed for growth (Humphreys, 2011). The rooting ability of

Festuca arundinacea, a Fescue species which has a deep rooting system, especially when

compared to Ryegrass, allows more access to water resources.The structuring of soil

from the rooting system also improves the water retention, further improving the

fescue’s ability to withstrand drought conditions and adding to its chararcteristic traits

desired for reclamation projects (Humphreys, 2011; Durand et al., 2007).

22

Plants also have an integral part in the aggregation process forming the soil structure,

by providing SOM. This acts as the foundation for the aggregate creation. Greater

aggregation ensures further protection of particular organic matter which is an essential

nutrient supply for plants and microbial communities (Wick & Daniels, 2009).

1.7 Other benefits of using vegetation as a reclamation tool

Vegetation can also create an economic value by becoming a productive landscape or

serve as an ecological value to the site and generally improve the aesthetic value of the

landscape (Hobbs & Norton, 1996; Wong, 2003). As mentioned before, native soil that

would support vegetation is typically degraded or lost, which is a major issue that affects

reclamation success. For vegetation cover to be successful, the reclamation

management must include careful deliberation over the vegetation chosen, referring to

the chemical, physical and biological properties of the substrate material (Sheoran et al.,

2010). The parameters of the chosen vegetation are vital, due to the challenging

environment determining the ability to establish, grow, disperse and reproduce under

harsh conditions (Barnhisel & Hower, 1997).

1.8 Grassland beneficial use within reclamation projects

The restoration team at Miller Argent site at Merthyr Tydfil, have chosen grassland as

part of their reclamation programme due to the effective ground cover provided but

also due to the rooting traits which improve stabilisation and filter surface water. Miller

Argent look to use the grasslands for commercial production as grazing and for

harvesting. The grasslands also have potential for environmental benefits which include

biodiversity through food source and habitat for fauna, above and below ground (Miller

Argent, 2015). Plantations can also be used on reclamation sites, but the Miller Argent

23

site specifics meant that trees could leave the land liable to initial surface erosion

(Weetland et al., 1985) and the compaction meant there was a risk of limiting tree

growth (Forestry Research, 2015; Moffat, 2006; Kuznetsova, 2011). A relamation goal

for the project, is to be commecially viable and sustainable, but in this case trees are

liable for additional maintenace costs and limited yeild, compared to the potential that

grasslands offers (Giardina et al., 1995; Filcheva et al., 2000; Karr,2002).

A successful grassland mix and management can have numerous reclamation benefits

including; aeration, greater drainage, circulating nutrients, stabilising pH, producing soil

organic matter,encouraging microbial activity / mineralisation, forming soil aggregates,

retaining mositure and creating greater soil structure and stabilisation through rooting

systems (Richards et al., 1993).

Grassland have been widely used for reclamation in Wales due to the relatively fast

surface cover and its ability to be self-sufficent without long term additional nutirent

requirements. Grasslands offer a permanent vegetation cover which has great potential

to be self-regenerating and can be utilised for recreational, commericial productivity or

conservation, within a challenging environment (high acidity, low nutrients, limited soil

water) (Halofsky & McCormick, 2005). Re-vegetating can initially reverse the site’s

degradation by limiting surface erosion through the surface vegetation cover and

stabilising soils with their extensive root systems (Li, 2006). However, the advantageous

qualities of grass species for reclamation, such as agressive growth, are also issues due

to dominance which can hinder diversity and growth of other symbiotic species such as

legumes (Halofsky & McCormick, 2005). Legumes are advantageous to grass mixes

because of the volumes of nitrogen that can be fixed within soils. Nitrogen fixation is

24

created by the associated bacterium that exists within their root nodules. Commercial

grasslands including legumes can fix several hundred kilos of nitrogen per year (Hart &

August, 1988; McQueen & Ross, 1982).

1.9 Grass species used within the commercial sector and reclamation projects

As mentioned previously, grass species have been widely utilised within commercial

recreational sectors and reclamation projects. However, the specific species used or

cultivars of that species, is dependent on the beneficial traits the individual exhibits. The

following section will describe some of the most popular species used within the Uk.

1.9.1 Perrenial Ryegrasss Lolium perenne

One of the most common and widespread native grasses found in the UK is the Perennial

Ryegrass Lolium perenne. This species is commonly used throughout UK lowlands in

arable leys and hay meadows, but it is also found in recreational areas, road verges and

rush pastures, to name a few (BSBI, 2014). This species can withstand moderate grazing

pressures, hence been widely sown in grasslands with livestock (Wildlife Trusts, 2015).

The breeding of Lolium species has centred around favourable growing conditions and

therefore these cultivars are vulnerable in less favourable conditions, such as the

uplands. Perennial Ryegrass is best suited to fertile soils, with ample moisture, but

within soils that are well drained and it thrives with additional moderate levels of

fertiliser. However, the grass can exist on poor soils due to its attribute of rapid re-

establishment (Christians, 2012).

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1.9.2 Fescue Fustuca

Another grass species used in the UK agricultural sector, is the Fescue genus (Festuca

spp.). Numerous Fescue species are utilised for their grazing qualities due to their

durability and their ability to withstand drought. A dynamic grass native to Europe,

fescues can tolerate several soil types, as well as a varied scale of light exposure and

availabiity of water, making it in diverse climates and environmental conditions across

the world. Fescues have been utilised for restoration projects because of their

commercial value for increasing productivity. They also offer good coarse ground cover

and deep rooting, which combine to both reduce surface erosion and particulate erosion

(Fribourg et al., 2009).

1.10 The breeding of grasses in the UK

Grasslands have been the UK’s prefered production of fodder for livestock and also for

recreational uses. Currently at least 75% of the UK’s agricultural land is grassland and it

is commonly the primary source of income for farmers. Consequently, the majorty of

breeding research has focused on the agronomic characteristics relating to herbage to

benefit livestock, focusing on grass production and seasonal spread attributes (Thomas

et al., 2003). Breeding has historically focused on improving nutrition and enhancing the

grasses traits (tolerance and endurance) to combat environmental pressures (Nedělník,

Macháč, & Cagaš, 2009).

1.11 Recent development of Festulloliums and potential benefits for reclamation

projects

Aberystwyth University have bred a grass with attributes of both Lolium spp. and

Festuca spp., creating Festulolium species, as a response to global demands to develop

26

grass productivity and environmental services in the face of climate change. The species

are closely related grass genera, which has aided the the interbreeding of both species

(Humphreys, 2015). These species have been known to interbreed naturally within the

UK due this close relations (O’brian, et al., 1967). IBERS has focused on enhancing

popular cultivated grass yields and its efficiency of water use. Success so far has included

the significant (88%) yield enhancement of Lolium multiflorum, by incorporating

favourable drought resistent Fescue genes (Humphreys, 2011). Combining both species

offers the opportunity to increase fodder quality combined with resistance and

persistence within harsh climatic conditions. This has created a geneotype which

displays traits more tolerant to conditions predicted by changing climatic conditions,

including drought and flooding (Humphreys et al., 2003), but also suitable for

challenging environments such as coal reclamation sites.

1.11.1 Festuloliums potential to provide environmental services

Festuloliums also have the opportunity to provide other environmental services below

ground. Similiar to many grasses, the root systems of Festuloliums, due to their growth,

turnover and architecture (Humphreys, 2011), can enhance soil microbial biodiversity,

carbon sequestration, provide flood mitigation and even bioremediation. By breeding

advantage traits of parental species, festuloiliums can benefit reclamation , potentially

more than any other grass species is currently capable of. Evidence suggests that

Festuloliums could play a potential role in ecosystem rehabilitation through enhancing

soil structure and stabilisation and vegetation establishment, plus environmental

services such as carbon capture and flood mitigation (Humphreys, 2005).

27

The potenital to accumulate carbon in soil from the atmosphere has gathered global

interest, as a potential approach to decreasing atmospheric CO2 (IPCC, 2007). Carbon

sequestration has been dicussed broadly in the literature, including its feasibility (Smith

et al., 2007; Schlesinger, 1990; Jenkinson et al., 1991; Juwarkar et al, 2010). It has been

suggested by Thomas et al., (1996) that vegetation has the ability to accumulate carbon

in subsurface soils. Hungate et al., (1997) explained that amplified CO2 frequently

encourages photosynthesis, consequently creating the opportunity for the terrestrial

biosphere to sequester carbon at a greater rate. Interestingly, several studies have

suggested that most plants will sequest larger volumes of carbon as a response to

greater volumes of atmospheric CO2 and consequently litter production, root exudation

and root turnover, as increased. Thus, the soil will potentially receive greater nutrient

supplements and a more enriched carbon cycle from additional plant biomass, root

development and capability to sequest more carbon. This suggests that grasslands could

not only improve reclamation sites, but also sequester carbon within a changing

atmospheric environment (Humphreys, 2011). Luo et al., (1996) extensive studies on

Californian sandstone grasslands found that the majority of grasses exhibited a positive

correlation between the plant biomass and below ground respiration, highlighting the

possibility that increased above ground growth could also indicate that there are

corresponding benefits below ground with microbial activity.

1.11.2 Festuloliums commercial potential

Field studies in Aberystwyth found that other Festulolium hybrids, L. perenne × F.

arundinacea var. glaucescens (LpFg) and L. multiflorum × F. arundinacea var.

glaucescens (LmFg) produced high yields similar to parental Rye grasses (Humphreys et

28

al., 2014). However, it is expected that L. perenne × F. mairei (Lpfm) would express

greater resilience to drought and heat than LpFg and LmFg (Wang and Bughrara, 2005).

Again all three showed the high growth rate typical of Lolium and the root strength and

depth of fescues (Humphreys et al., 2014). Plant-soil interactions are yet to be fully

assessed but it is reasonable to suggest the Festuloliums are able to improve SOC

capture with additional restoration benefits such as improved microbial activity

(MacLoed et al., 2013). Therefore, in areas such as reclamation sites where yield would

be stunted due to challenging abiotic and biotic conditions, the agronomic value of the

site could be potentially boosted using these grasses (Humphreys et al., 2014).

1.11.3 Festulolium potential as a reclamtion tool

As mentioned earlier, grasslands, like most vegetation, have the ability to enhance soil

structure and rehabilitate degraded material through the morphology and physiology of

grassland root systems. Deep grass roots can directly stabilise soils, limiting erosion and

therefore aiding the recovery of damaged ecosystems. The stabilisation can also

consequently retain pollutants so that they enter water systems less easily (Jones et al.,

2011; Humphreys, 2011).

Another grass bred by IBERS, Festulolium loliaceum ‘Prior’, (L. perenne x F. pratensis),

illustrated in a hydrological field experiment its superior ability to aid soil water

retention and filtration. Compared to six other graases, including its parental species,

Festulolium loliaceum cultivatars reduced runoff by 65% whilst L. perenne only managed

30% and F. pratensis 50%. Further laboratory analyses of all cultivators used in the field

experiment, revealed that the Festulolium root growth and turn-over were the major

reason behind these results compared to the parental species (Humphreys, 2011). The

29

initial rapid deep rooting of the Festulolium, is followed by significiant root degradation

at depths, creating porous and structured soil, benefitiing water rention and filtration,

which accounts for its capability to reduce runoff (Cookson, 2013). However, whether

Festulolium loliaceum ‘Prior’ would express similar results in most reclamation sites is

questionable, due to the experiment only using a clay rich soil. Also, investigations

analysing the ability of this species to reseed which resulted in highly variable results

depending on location, weather and climate (Humphreys, 2011). It appears the grass

can provide a commercial use and mitigation to flooding, but whether it is possible

within a challenging growth environment, such as a reclamation site with poor

substrate, needs to be investigated. A report by Macleod et al., (2013) explained that

the Festulolium loliaceum cultivars displayed more roots which were larger and

penetrated consistently deeper than those of L. Perenne cultivars. These characteristics

could reduce compaction by providing soil porosity, helping stabilise land, give

resistence against drought and aid establishment, all of which are challenging features

common to reclamation sites (Humphreys, et al., 2013).

Festulolium could provide SOM within challenging coal mining reclamation conditions.

Nutrients from dead plant matter above and below ground are released through

decomposition into the lower soil horizons (Gerrard, 2003). Soil organic matter from

grasses could have three vital functions within reclamation material, which other plants

could benefit from. Physically, the matter influences the structure of the soil by

stabilising, helping develop the upper horizon’s ability to retain water and it also has a

thermal quality. Biologically, it is vital as a source of energy and a reserve of nutrients

for living animals, plants and microbes. Organic matter brings resilience to soil and the

species that rely upon it (Osman, 2013). The chemical composition of soils is highly

30

affected by the volume/ content of SOM. This can aid cation exchange and directly affect

the stabilisation of soil pH, which can consequently have a direct impact on the species

that can exist with soil material. Importantly, organic matter enhances the buffering

effect so fluctuations in the availability of nutrients and fluctuations in pH level are

limited. Soils are therefore better equipped to absorb more nutrients due to the organic

matter and also release them due to the cation exchange (Gerrard, 2003). All of these

functions interact in a dynamic form, which the literature suggests is not fully

understood (Bradshaw, 1983; Bradshaw , 1997; Sheoran et al., 2010).

1.12 Why would microbial activity be crucial for reclamation sites?

The material that is typically used on reclamation sites has limited biological activity. A

healthy ecosystem needs soil biota so it can sustain a natural cycle of nitrogen and

carbon, improve soil porosity and composition of CO2 and organic acids, and all of these

are crucial for plant growth (Edgerton et al., 1995). The microbial communities within

the soil have a vital role of decomposing plant material, having a symbiotic relationship

with plants allowing the uptake of phosphorus and nitrogen. Additionally, plant growth

is enhanced through microbial production of polysaccharides, which also increase soil

aggregation (Williamson and Johnson, 1991). Single celled bacteria called Rhizobia also

are integral to legumes by converting atmospheric nitrogen into a usable form of

ammonia for plants (Gil-sotre et al., 2005). The literature investigating the quality and

recovery of mine soils suggest that both organic matter and the microbial populations

should be assessed as these are key indicators to gauge soil quality and are essential for

soil recovery (Schafer et al., 1979).

31

Microorganisms within the soil use the soil organic carbon energy source and therefore

the total organic carbon is crucial for productivity and fertility of the soils (Edwards et

al., 1999). Soil organic matter is a major sink of soil organic carbon , thus the amount of

SOM can directly and indirectly drive the metabolic activity of microorganisms. Field and

pot experiments by Williamson & Johnson (1991) analysed the ability of Ryegrass to

accumulate microbial biomass from fertiliser, and they found that the carbon within the

soil was the limiting factor instead of phosphrous or nitrogen. However, the

investigation did only analyse the initial year of a coal mine reclamation project

Moreover, Malik & Scullion (1998) study of UK coal mine reclamation sites found that

the total SOM and SOC, accumulated over time and within the initial year the amounts

were miminal. Ussiri et al., (2006) explains that reclaimed mine soils typically have very

low soil organic carbon due to the considerable proportion of shattered and

disintergrated rock material.

Festuloliums and other grasses, may have the ability to provide enhanced soil properties

to protect microbial populations, create stablised soils and provide the SOM and SOC

needed to stimulate the development of microbrial populations.

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1.13 Gaps in Knowledge

As the literatre review suggests, the potential benefits that grasslands could provide for

a reclamation project are vast. The vegetation cover and root systems have the

capability to limit surface erosion, increase water infiltration and then enhance soil

properties and the species that exist within it. The advanced investigations into

Festuloliums suggest that the traits of these new hybrids would make them suitable

candidates for application to reclamation of coal mine sites. However, the relationship

between the Festuloliums and the soil are still relatively unknown. In recent field

experiments cultivars of Festuloliums have displayed properties which decrease surface

runoff. Laboratory investigations have also shown they have greater dispersal of roots,

which die back, creating greater porosity and turnover of roots within the soil,

potentially improving microbial populations, SOM and consequntly the SOC within soils.

The Miller Argent site at Merthyr Tydfil that is being investigated in this study, was

previously investigated by between 2013 and 2014 (Chilver, 2014). Findings from her

investigation on the same experimental plots found that all four Festuloliums (LpFg,

LpFg2, LmFm & Prior) were capable of establishing and surviving on the reclamation

materials ( weathered shale, soil forming material, overburden shale and boulder clay).

Moreover, the Festuloliums created greater herbage compared to all parental Fescue

and Ryegrass cultivars also investigated and the soil forming material was the greatest

substrate for the total herbage yield. The study concluded that the Festulolium LpFg

created both the greatest root development and above ground biomass, compared to

all cultvars investigated. An additional greenhouse investgation using a non-destructive

imaging system was unable to correlate with field herbage and root results. The vastly

33

different abiotic and biotic conditions between the field and greenhouse experiements

were concluded to be the reason for the different responses.

Chilvers’ study stated that due to field soil conditions, only one replication of soil sample

of each cultivar was obtainable from each test plot. Key findings relating to SOM and

root mass are therefore in need of further investigations. Root mass was expected to be

correlated with above ground biomass throughout all test grasses, but this was not the

case, except for LpFg.

The study was only within its initial year and as highlighted by Chilver (2014) and other

literature sources ( Sopper, 1993;Malik & Scullion, 1998), the total amount of SOM

would be slight, accumulating with time. Therefore following on from Chilver (2014)

findings, the overall investigation could benefit from an additional year and further

measurements. Also, due to the exceptional drought conditions experienced in 2014,

further field analyses of yield could provide a more accurate reflection of the cultivars

potential, especially as some grasses have differing initial establishment capabilities. As

the field experiment enters its third year, results may give a better undertanding of plant

dynamics and soil interaction after initial establishment. Another important area that

Chilver (2014) was unable to investigate, was the soil microbial population within soil

materials and whether the different cutivars had an effect on these. This is crucial for

the breakdown of dead plant litter into SOM. Therefore, further investigations into this

would provide a better understanding of the cultivars and the soil material’s ability to

maintain these populations.

Therefore, there is a need to determine if there is a relationship between the cutivars

and the different soil materials. Furthermore, whether there is a difference between the

34

parental species and Festuloliums cultivars. Literature has highlighted that vegetation

and soil dynamics might change over time, so investgations into cultivars and the effects

of material on yield is also beneficial within the third year of this study. To investigate

this initially, microbial population, root distribution and mass, SOM and herbage will be

investigated. Also, the literature has highlighted that the quality of minespoils may

deteriorate through weathering. Therefore the materials will be investigated to analyse

if the materials have an effect on the cultivars and whether this agrees with Chilver’s

(2014) study. The results should provide an indication of the potential uses of

Festuloliums within reclamation projects for coal mines and the findings could be

applied to other Welsh sites.

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1.14 Hypotheses

Festulolium cultivars will create greater herbage yield and ground coverage compared

to their parental species.

Festulolium cultivars will have a greater root development within material compared

with their parental species.

Festulolium cultivars will create greater SOM and an enhanced microbial activity

Materials will differ in their potential for reclamation objectives

36

2. METHODOLOGY

This study has incorporate field research from the Ffos-y-fran site, Merthyr Tydfil and

laboratory experiments on field samples at the Institute of Biological, Environmental &

Rural Sciences (IBERS), Aberystwyth University. The following section will explain the

method of investigation.

2.1 Study site

The experimental plots are located within the site managed by Miller Argent which is an

opencast coal mining project, which is jointly owned by Argent Group plc, The Miller

Group Ltd and Bernard Llewellyn LP. The Ffos-y-fran site is located north east of Merthyr

Tydfil, South Wales, UK, Grid reference: SO 09161 06092 (see Figure 1 ) and this is one

of the largest opencast coal mines in Europe. The site covers 3,500 acres, it opened in

2005 and it is expected to extract 11 million tonnes of coal over 15 years. The

reclamation of this third and final phase is part of the former East Merthyr Reclamation

Scheme and is the largest of all three.

37

Figure 1. Location of the Miller Argent site

Left: Location of the site is marked with a red circle, highlighting its positon in the South of Wales, United Kingdom. Right: Location of the Miller Argent : Phase III site and the locality of the town Merthyr Tydfil. The right circle marks the actual site.

Photographs from Bing (2015)

2.2 Miller Argents reclamation aim

The aim of the reclamation scheme, partnered by the Welsh Development Agency, is to

restore derelict and dangerous land. The previous two phases have restored land for

residential, industrial and recreational use. The third reclamation phase aims to restore

the land for recreational use which encourages local biodiversity. See Figure 2, for the

aerial picture of the site prior to the third and final phase of extraction.

38

Figure 2. Aerial photograph of the Miller Argent site at Merthyr Tydfil. The photograph was taken prior to the extraction of coal, part of the third phase of extraction. The Red circle highlights the location of the experimental plots, which have been investigated in this study. Photograph from Miller Argent (2015b)

2.3 Climate

The Merthyr Tydfill climate is essentially a maritime climate, which typcially can be

characterised by mild weather but frequently wet, cloudy and windy. However, the local

uplands are prone to harsh and dramatic flucuations in weather conditions.

Temperatures generally range from 0.5oC in winter to 19.5 oC in mid summer and land

is exposed to frost on 58.7 days of the year, mostly from October to April ( see Figire 3).

The area is prone to frequent unpredictable heavy rainfall throughout the year, but the

39

months of June and July can be prone to prolonged periods of drought (Met Office,

2015). This was especially the case for (Chilver, 2014). Average rainfall for the area is

1674mm (Met Office, 2015).

Figure 3. Weather data collected from Miller Argent weather station, displaying climatic variations and individual field experiments and applications of fertiliser.

The blue bars represent the total rainfall (mm) for each month, whereas the green line represents the mean temperature throughout the months of the 2014/2015 investigations. Also highlighted in annotation boxes are the months of which the cuts were taken of the grass from the material plots. Furthermore, annotation boxes include when fertiliser was applied to the plots, when soil samples were extracted (.SS.) and when percentage coverage of grass species (.% C.) was assessed.

40

2.4 Geology

The soil parent material in the site is classified as carboniferous shale and sandstone.

Drift on site is from the Palaezoic sandstone mudstone. The underlying geology has

influenced the low fertility of soil on site (Cranfield University, 2015).

2.5 Soil properties

Soils associated with this area are typically Wilcocks 1 721c, which have fine loamy thin

topsoil’s over upland clayey soils and peaty horizons. These tend to have poor

permeability and therefore are liable to waterlogging. Areas which have been restored

from the opencast mining will have similar characteristics but are classified as “Neutral

Restored Opencast 962” soils and have no peaty horizons, thinner topsoil’s and material

is often stony with fragments of coal (Cranfield University, 2015).

41

2.6 The field experiment

The following section will describe in detail the field experiment

2.6.1 Experimental plot design

Four plots of materials measuring 4 metres by 6 metres, all 1 meter deep, were created

by Miller Argent in 2013, under guidance given by Aberystwyth University. Each plot

consisted of recovered material from the site and represented the available material on

the site for future restoration. These included weathered shale, soil forming material,

overburden shale and boulder clay material, all of which had been stored for an

extensive period before placing as the trail plots (Scullion, 2015; Humphreys, 2015;

Chilver, 2014). The plots were also subject to typical reclamation procedures, ripping

and cultivation, to relieve compaction and improve the filtration of water, thereby

improving the potential for plant growth and establishment (Taubman, 2015; Chilver,

2014). Using a single shank ripper, larger boulders were surfaced and removed with

mechanical cultivation, alleviating compaction and reducing stoniness (Taubman, 2015).

2.6.2 Grass species and plot layout

Each material plot, has been subdivided into 24 subplots measuring 1 metre by metre.

Every grass specie in this experiment has been replicated three times within each

material plot and each one of these has been allocated a subplot by a fully randomised

method. Refer to Figure 4, for the plot layout & design and also appendix 7.1,for the

species specific randomised design for all material plots.

42

Figure 4.Experimental plot layout and illustration of subplot divides.

Top: This photograph was taken of the actual experiment at the Miller Argent site at Merthyr Tydfil. The illustrations upon the photograph display the allocation of each material plot: A - Weathered shale, B – Soil forming material, C – Overburden shale & D –Boulder clay.

Bottom: The drawing design provides an impression of the subplots upon each of the four main material plots within which individual species were sown. Each subplot measured 1 metre by 1 metre.

Photograph and illustration by Gibson (2015)

43

2.6.3 Grass species chosen

The grasses allocated to the plots have been chosen due to their potential to provide a

productive crop with high yield, improve ecosystem rehabilitation, reduce surface run

off, limit erosion and enhance capability to provide environmental services to the

reclamation site. This section will provide greater detail of the grasses included.

2.6.3.1 Rye grasses – Aber Dart & Aber Magic

Since 1919, the IBERS institute have been breeding commercial grasses. One of their

great successes has been the ability to create greater sugar content in Perennial Rye

grasses, and as a consequence, enhancing meat and milk production in ruminant

species. The diploid (2x) grasses have been bred using two equal sets of chromosomes

from parent Rye grasses Lolium perenne, which has improved growth and digestibility.

The first commercial successful Rye grasses from IBERS, Aber Dart (Lp) and the recently

commercially released and developed Aber Magic (Lp), have been included in this

investigation for these traits and commercial potential. Aber Dart was the first High

Sugar Grass (HSG) to be released by IBERS. A three year field study by Farm Research in

New Zealand provided evidence that the grass was extremely persistent even amongst

harsh conditions due to its deep rooting and extensive tiller compared to 12 other

leading commercial grasses investigated (Tavendale, et al., 2006). The recent Aber Magic

has seasonal differences compared to Aber Dart: later flowering, longer dry herbage

potential and reportedly benefits from quick establishment in winter and spring

(Humphreys, 2015).

44

2.6.3.2 Fescues – Tall fescue Festuca arundinacea cv.Bn1482 & Meadow fescue

Festuca pratensis cv.Bf 1317

The beneficial traits of fescues have been mentioned previously (Section 1.11.2).

Fescues have had the evolutionary ability to hybridize naturally with each other. This

has given them the ability to colonize and adapt to challenging environments, which

could give greater potential for reclamation establishment and lower mortalities

(O'brien, et al., 1967).

Festuca pratensis cv.Bf 1317 (x2), has the ability to grow in a variety of soil types,

including heavy soils and clay. However, the species benefits from fertile soils and moist

conditions. The species is able to grow throughout low ranging temperatures and

includes frost tolerance (Humphreys, 2015).

Festuca arundinacea cv.Bn1482 (Hexaploid) (x6) is a species that has naturally

hybridized with Festuca pratensis and is a cool season grass that originates from

temperate climates, but is widespread from northern Europe to central Asia and

northern Africa. The wide distribution, with varying ecological environments, suggests

the grass can tolerate a range of temperatures, soil types and moisture (Kirigwi, et al.,

2004). The species expresses drought and heat tolerance and is used throughout

America and Europe due to its proven tolerance to stresses. Previous studies at

Aberystywth University, have isolated genes within Festuca arundinacea which express

traits for drought resistance. However, the species has been criticised by the farming

community for its slow growth and establishment (Humphreys, 2015).

45

2.6.3.3 Festuloliums

(LpFg - Perennial Ryegrass x Mediterranean Fescue, LpFg2 - Perennial Ryegrass x

Mediterranean Fescue (Partial hybrid), LpFm - Perennial Ryegrass x Atlas Fescue, Prior -

Perennial Ryegrass x Meadow)

The benefits and hybridization of Festuloliums and the traits that can be attributed to

them from their parental grasses have been describe previously (Section 1.10). All

Festuloliums included in this study, except for Lpfg2, are tetraploids (4x). These have two

sets of chromosomes from each parental Rye grass and Fescue. However, the Lpfg2 is

only a partial hybrid created by an introgression method, which backcrosses one

particular hybrid parent. Moreover, the Lpfg2 (Diploid) (2x) has the majority of its traits

from the Ryegrass, including its HSG traits, with only a few Fescue traits, consequently

increasing its tolerance to stresses only partially. The fescues included in the other

Festulolium mix include Mediterranean Fescue, which has traits of enhanced resistance

to drought. However, the Atlas Fescue is the most drought-resistant Fescue species

known (Humphreys, 2015).

2.6.4 Applied fertiliser

According to the studies by Chilver (2014), fertiliser was only applied to the experimental

plots after the initial 2013 seeding and once more after the first cut in 2014. This is a

low volume of fertiliser for grassland establishment in challenging abiotic conditions,

according to several sources (Humphreys (2015); Li et al., (2013)). However, Li et al.,

(2013) explained that reclamation sites have to contain lower fertiliser application

46

initially due to the complication of rapid growth consuming all nutrients applied and

reducing the vegetation’s ability to become sustainable. Two more applications were

applied, once in November 2014, after the first cut and again in May 2015. The Super

Cut fertiliser used throughout this study consisted of 23 % Nitrogen, 4% Phosphate, 7%

Sulphur trioxide and 13% Potassium. This is consistent with the investigation by Chilver

(2014). Fertiliser was applied at approximately 40 g/m2 subplot.

2.6.5 Herbage collection

Clippings of all 96 subplots were collected, using a visual judgement of the best growth

within each subplot to be a representative of the species growth. Vegetation growth

was then removed above the quadrat frame, leaving the thickness of the quadrat frame

(2cm) of grass to remain. All five sets of cuts throughout the investigation were

replicated consistently but the placement of the quadrat altered within each subplots.

Entire plots were mown after harvesting

2.6.6 Ground cover assessment

The method used to assess the percentage of grass that covered the ground within each

subplot was guided by studies from Floyd & Anderson (1987) and also Scullion (2015).

The ground cover of grass in each sub plot was estimated by dividing individual plots

into 25 sections. By using this aid and a photograph to guide (from the initial estimation

of vegetation cover), the estimation hoped to be kept consistent. Grass foliage and

tillage cover of ground were incorporated into the estimations.

47

2.6.7 Soil cores

As a consequence of the findings of Chilver(2014) studies, on the difficulties of extracting

soil cores in dry weather, soil cores were taken during a wet period of prolonged rainfall

in July 2015. Material cores were taken using a hammer head soil sampling auger with a

20mm outer diameter and 13mm inner diameter corer. Three locations within each sub

plot were chosen, cores were taken through the crown of the grass, as advised by

Scullion (2015). However, due to compaction, only a depth of 15cm was able to be

achieved. All samples were stored for 2 days and kept at 4oC refrigeration prior to

analysis in the lab.

2.6.8 Deep rooting distribution assessment

As a consequence of compaction, material cores deeper than 15cm were impossible.

Using a method adapted on site, sub-plots on the circumference of each material plot

were able to be assessed. Digging a 20cm by 45cm hole alongside the best growth grass

on the available subplots, gave an indication of root distribution at the depths exposed.

Roots were recorded at 5, 10, 15, 25 and 35 cm depths (refer to figure 5). Unfortunately,

this was only able to be replicated once on each material for each species, at best. Data

for some species is absent, due to not being allocated a subplot on the circumference of

that plot.

It is acknowledged that this will have excluded rooting behaviours of the grasses within

non- exposed areas and that this is only a small sample to provide an indication of root

behaviour at depths.

48

Figure 5. Illustration of the root distribution analyses and typical soil pit face which was excavated alongside subplots on the circumference of the plot.

The illustrations on the photo, express the depths at which root counts were recorded if they crossed this line.

Photograph and illustration by Gibson (2015)

49

2.7 Laboratory investigations

The following section will describe the laboratory investigations.

2.7.1 Root biomass

After all visual herbage and dry litter were extracted from the soil samples, a 2mm sieve

was used to extract stones from the samples. After trialling root extraction time periods

(2, 4, 6, 8 minutes), 4 minutes was determined the most justified allocation of time to

extract roots from all samples respectively. This was concluded appropriate due to the

majority of roots being removed in all test materials and the researcher’s available time

for root extraction. The method for root extraction and biomass assessment was guided

by Scullion (2015) and Benomar et al., (2013). Using tweezers, roots were removed from

each sample and excess soil removed using distilled water with gentle washing over a

600 μm diameter pore size sieve. All roots were placed within pre-weighed labelled

pyrex test tubes, then subjected to 72 hours drying at 70oC in an air forced oven and

then re-weighed. All fine soils and stones were also dried and weighed.

2.7.2 Herbage dry matter

All samples were placed into individual paper bags and were dried at 70oC for 72 hours

in an air forced oven. Dry weight was recorded.

50

2.7.3 Soil organic matter (SOM)

The weight loss-on-ignition (WLOI) method was used to analyse the amount of SOM

within soil samples. This method is widely used and accepted (Salehi, et al., 2011;

Scullion, 2015, ,Yerokun, et al., 2007) as a reliable procedure to assess the SOM within

soil samples. Samples were initially dried in an air forced oven for 72 hours at 70oC to

remove moisture. The samples were then ground using mortar and pestle to expose

material further, as the literature has highlighted that ignition of compacted soils is

unreliable if left in their natural state (Ravindranath & Ostwald, 2007). Due to the high

coal carbon content expected in the samples, these were placed at 300oC (below the

ignition temperature of coal) and 400oC, which is an accepted temperature for oxidation

of SOM / organic carbon (Jackson, 1985). Two temperatures were used due to the coal’s

potential to give false SOM weight loss readings (Salehi et al., 2011). Data collected

through calculations represented an indication of the SOM lost through the process of

WLOI.

2.7.4 Soil respiration assessment

The soils were assessed for respiration to investigate the level of biological activity

within the material. This can also give an indication of the SOM and its decomposition

(nutrient cycle).

Soil moisture within field samples was initially investigated. A 5g sample of each material

was weighed and placed within an air forced oven at 70oC overnight. The samples were

weighed again and the loss of weight was attributed to moisture content and evidence

suggested that the samples were distinctively different from one another (Weathered

51

shale - 9.32%, Soil forming material - 12.37%, Overburden shale - 9.55%, Boulder clay -

15.4%).

After thoroughly mixing each raw core from their respective subplot, 10g of material (<

2mm) was placed within 50ml plastic centrifuge test tubes and sealed with parafilm.

(This sample represented the moisture conditions of the field). After 5 days of dark

storage with an average temperature of 21oC, a 5ml air sample was withdrawn from

each tube using a syringe. Using an “Environmental Gas Analyzer” (EGM-4, PP system)

to record the CO2 quantity within air samples via infrared measurement techniques, the

concentration of CO2 was recorded. This procedure was advised by Scullion (2015) and

partly used by Jenkinson & Powlson (1976).

A second set of samples were investgated using additional moisture (1ml of distilled

water) which was added to the samples with moisture content under 15%. This was to

aid microbial activity and create a closer unity of moisture across all samples. Rewetting

and creating a moisture content between 15-18% was advised by Scullion (2015) and

studies by Fierer et al., (2003) .

2.8 Statistical analyses

All data collected from this investigation has been statistically analysed using the “IBM

SPSS version 22 statistical Analyse package”. Whilst testing for homogeneity of variance

using the Levenes test, the data sets had generally a highly significant spread of variance,

which was also apparent when viewing the Standard Deviations for each set.

Transforming the data using LOG10 was unable to remedy the distribution of data, except

for Cut 3 and CO2 data sets. Therefore could not meet the equality of error variance,

which is an assumption needed to complete the Two Way ANOVA. However, whilst

52

running the Two Way ANOVA it was clear where factors were having a significant effect

and this provided indications for the non-parametric tests to investigate further (Pallant,

2010).

Utilising the non-parametric Kruskal-Wallis analyses, which has stricter requirements to

meet significance, the data sets were able to be statistically analysed for significant

differences between factors. Subsequent investigations using Post Hoc Tukey HSD tests,

to identify where the differences were within these factors (Bonamente, 2013).

53

3. RESULTS

Field data was collected onsite at the Miller Argent site at Merthyr Tydfil from November

2014 through to August 2015. Research focused on three main subjects: grass growth,

root development, and the soil/grass interaction. The overall aim of the experiment has

been to identify key traits of grasslands which could assist the reclamation of the coal

wasteland site and its potential after use value. These include the potential herbage,

SOM provided, root development, and respiration of the soils. The grass species

investigated included four parental grasses which acted as the control species within

this experiment. These consisted of two Fescue cultivars, Meadow Fescue (Festuca

pratensis cv. Bf1317) & Tall Fescue (Festuca arundinacea cv.Bn1482) and two HGC

Perennial Ryegrass cultivars, Aber Magic and Aber Dart. These four parental grasses

have been tested against four hybrid Festuloliums that have varying quantities of traits

from their parental grasses and moreover, a range of potential benefits for use on

materials and conditions that exist in coal reclamation sites. The Festuloliums

investigated included LpFg (Perennial Ryegrass x Mediterranean Fescue), LpFg2

(Perennial Ryegrass x Mediterranean Fescue –Partial hybrid), LpFm (Perennial Ryegrass

x Atlas Fescue), and finally Prior (Perennial Ryegrass x Meadow Fescue). Three replicates

of each species were randomly allocated a 1m x 1m sub plot making 24 subplots within

four separate soil materials. These plots represented materials available on site for a

potential grassland reclamation project. These included weathered shale, soil forming

material, overburden shale and boulder clay. The shales have been extracted from

depths, therefore have limited nutrients and unfavourable texture for vegetation

54

growth. Whereas, both the boulder clay and soil forming materials represent material

that would be typical better suited as a replacement topsoil. All materials have been

stored for three years and exposed to weathering prior to the creation of the

experimental plots .This investigation has gathered data that represents the

experimental plots and cultivars in their third year after establishment in 2013.

Due to the nature of the field plot design, variance within grass species and the materials

in which they were sown has increased throughout the three years of the trial. The

statistical analyses of the data have been particularly challenging. Typically, to compare

the two independent factors against eight dependent factors, a Two Way ANOVA would

be utilised. Unfortunately, due to the considerable distribution range of the data

collected from the subplots, the variance was too dissimilar to meet the required

assumptions of a Two Way ANOVA. All data sets failed the homogeneity of variance,

Levenes test and even with transformation (log 10) the issue was not sufficiently

corrected across all data sets (Appendix 7.8). By ranking data and using a non-parametric

test (Kruskal-Wallis) plus a post hoc test, (tukey), significant differences were able to be

identified. Where both independent factors had a significant effect, the background

interference with each other was tackled by isolating each material plot and conducting

a One Way ANOVA with a Post Hoc, Tukey HSD test. The specific statistical analyses

procedure for each item investigated can be located in Table 1.

The Two Way ANOVA showed that there was no significant interaction found between

the set of two independent factors throughout the data collected, so this was not

55

investigated further the independent factor being the soil material type and the range

of cultivars.

56

Table 1.Statistical analyses procedure for each individual investigation.

The results for the Levenes test of homogeneity are displayed to illustrate the variance issues even after transforming data. The Two Way ANOVA indicated where the significance between groups could be found and the further statistical analyses section, shows the additional analyses where necessary.

Investigated Result of Levene test for Homogeneity of Variances

Result of Levene test using transformed data (LOG10)

Two Way ANOVA indicated effect significance >0.05

Further Statistical Analyses

Grasses Soil

Cut 1 0.000 0.003 No No None

Cut 2 0.000 0.000 Yes No Kruskal-Wallis followed by a post hoc, Tukey.

Cut 3 0.015 0.251 Yes Yes Separated investigation into four separate soil plot and used a One Way

ANOVA ,followed by a post Hoc, Tukey

Cut 4 0.000 0.004 Yes Yes One Way ANOVA on each effect ,followed by a post hoc, Tukey

Cut 5 0.000 0.021 Yes Yes One Way ANOVA on each effect ,followed by a post hoc, Tukey

Total herbage 0.000 0.000 Yes Yes One Way ANOVA on each effect ,followed by a post hoc, Tukey

SOM at 300c 0.000 0.000 No Yes Kruskal-Wallis followed by a post hoc, Tukey.

SOM at 400c 0.000 0.000 No Yes Kruskal-Wallis followed by a post hoc, Tukey.

57

Respiration (Co2) 0.000 0.001 No Yes Kruskal-Wallis followed by a post hoc, Tukey.

Respiration (Co2)

with additional

moisture

0.000 0.000 No Yes Kruskal-Wallis followed by a post hoc, Tukey.

Root mass 0.031 0.002 Yes Yes Separated investigation into four seperate soil plot and used a One Way

ANOVA ,followed by a post hoc, Tukey

Percentage

coverage

0.000 0.000 Yes No Kruskal-Wallis followed by a post hoc, Tukey.

58

3.1 Herbage analyses

Grass samples from each plot were collected in five separate cuts from November 2014 to

August 2015. The duration of time between cuts was not standard, however, so between May

and August cuts were approximately every month. Throughout the histograms shown will

show result the calculated mean amount of herbage created by each cut.

This section will investigate individual cuts and the dry herbage collected from each group.

3.1.1 Cut One

Using a Two Way ANOVA, cut one was found to have no significant combined effects from

either the grasses and/or materials, relating to the total herbage. However, according to the

post hoc test, Prior and boulder clay produced the most herbage, and LpFm produced the

least. Soil forming material produced the least volume of yield. Due to no significant

differences at this stage, no further analyses were conducted.

3.1.2 Cut Two

Using a Kruskal-Wallis test, only the grass cultivars had a highly significant effect on the

herbage collected (X2 = 26.961, p = 0.000), refer to Table 2, for individual mean totals. The

following post hoc test, revealed that Bn1482 created significantly more than all of the other

species (P <0.05). All Festuloliums produced less than all parental species (see Figure 6). The

soil material did not have a significant effect on the herbage. However the post hoc test

indicated that the soil forming material did have a significantly great herbage than overburden

shale and boulder clay (P < 0.05).

59

Figure 6. Total mean herbage (dry weight) collected from each group of grass cultivars from cut two. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

3.1.3 Cut Three

The Kruskal-Wallis test indicated that grass cultivars had a significant effect on the herbage

collected (X2 = 18.495, P = 0.010), refer to Table 2, for individual mean totals. An additional

post hoc test identified Bn1482 as producing the most overall herbage but only significantly

greater (p<0.05) than Aber Dart, Aber Magic, LpFg2 and highly significantly greater (p<0.001)

than LpFg and Bf1317.Two Festuloliums, Lpfm and Prior, produced the second and largest

amounts of herbage. Both cultivars were significantly greater (P<0.05) than the Fescue Bf1317

(See Figure 7).

60

Figure 7. Total mean herbage (dry weight) collected from each group of grass cultivars from cut three. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

Materials also were having a highly significant effect on the herbage produced (X2 = 39.442, P

= 0.000), refer to Table 3, for means totals. According to the post hoc test, the weathered

61

shale created the greatest herbage total yield and was significantly greater (P < 0.05) than soil

forming material and highly significantly (P <0.001) greater than the others (See Figure 8).

Figure 8. Total mean herbage (dry weight) collected from each group soil material from cut three. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

A One Way Anova and post hoc, tukey test were used to statistically analyse each data set

from each material to isolate difference and limit background variability originating from both

independent factors. On both soils forming material and boulder clay materials, Bn1482

produced the most herbage and consistently created significantly (P < 0.05) more herbage

62

than Bf1317 and LpFg. Moreover, Bf1317 produced the least on all materials except soil

forming material.

On the weathered shale there were no significant differences in the herbage created (P> 0.05).

However, on overburden shale, Bn1482 again created the most herbage and was significantly

greater than LpFg and Bf1317 (P< 0.05).

3.1.4 Cut Four

The Kruskal-Wallis test indicated grass cultivars as having a highly significant effect on the

herbage collected (X2 =41.653, p = 0.000), refer to Table 2, for mean totals. An additional post

hoc test revealed that the Bn1482 produced a highly significant yield (P < 0.001), more yield

than all other species. The Fescue Bf1317 produced the least and was significantly lower (P <

0.05) than both Ryegrasses (Aber Dart & Aber Magic), refer to Figure 9.

The materials did not have an overall effect on the total herbage according to the Kruskal-

Wallis test.

63

Figure 9.Total mean herbage (dry weight) collected from each group soil material from cut four. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

3.1.5 Cut Five

The Kruskal-Wallis test indicated grass cultivars as having a highly significant effect on the

herbage collected (X2 = 37.353, P = 0.000), refer to Table 2, for individual mean totals. The

post hoc test identified Bn1481 as consistently creating the greatest amount of herbage

compared to all other species, at a highly significant (P < 0.001) difference. Festulolium

cultivars LpFm and LpFg produced the least herbage overall, with LpFm also producing

significantly (P < 0.05) less than Bf1317 (refer to Figure 10). It was worth noting that the LpFg

64

had a P value = 0.053, compared to Bf1317, which indicated that the Festulolium was very

close to creating significantly less herbage.

Figure 10. Total mean herbage (dry weight) collected from each group over all four materials during cut five. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

Materials also were having a highly significant effect on the herbage produced (X2 = 16.599, P

= 0.001), refer to Table 3, for mean totals. The post hoc test identified the soil forming material

as giving the greatest herbage total yield and was significantly greater (P < 0.05) than both

weathered shale and overburden shale but not boulder clay.

65

A One Way ANOVA and post hoc, tukey test were used to analyse each data set for each

material to isolate difference and limit background variability originating from both significant

independent factors. There was not a significant difference between the cultivars within the

weather shale and boulder clay materials. However, the cultivars within the soil forming

material expressed a highly significant difference (P< 0.001) and a significant difference (P<

0.05) was expressed between cultivars within the overburden shale. Bn1482 produced the

greatest yield overall in both materials. On the overburden shale, Aber Dart produced the

second greatest herbage volume and Bn1482 was significantly greater (P>0.05) than LpFg,

LpFm, Prior and the lowest producer, Bf1317. However, on the soil forming material Bn1482

was highly significantly greater (P<0.001) than LpFg and significantly greater (P<0.05) than

LpFm, moreover Bf1317 produced the second largest volume, and was significantly greater

(P<0.05) than LpFm.

3.1.6 Total Herbage

This section describes the analysis of the cumulative total herbage collected throughout all

cuts.

The Kruskal-Wallis test indicated grass cultivars as having a highly significant effect on the total

herbage collected (X2 = 29.586, P = 0.000), refer to Table 2, for individual mean totals. The

post hoc test, revealed that Bn1482 total herbage was highly significant (P <0.001) greater

than any other cultivar monitored over all materials, refer to Figure 11.

66

Figure 11. Total mean herbage (dry weight) collected from each group of grass cultivars over all four soil materials. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

Materials also had a highly significant effect on the total herbage created (X2 = 16.407, P =

0.001), refer to Table 3, for means totals. An additional post hoc revealed that the soil forming

material created the greatest herbage total yield, but only significantly greater (P < 0.05) than

the worst material, overburden, which also produced significantly less herbage than

weathered shale, but not boulder clay.

A One Way Anova and post hoc, tukey test were used to analyse each data set on each

material to isolate difference and limit background variability originating from both

67

significantly independent factors. There was no significant difference between cultivars on

weathered shale and boulder clay. However, there was a significant difference (P < 0.05) on

the soil forming material and overburden shale. Bn1482 created the greatest total herbage on

both materials and was consistently significantly (P >0.05) greater than Bf1317, LpFg and Lpfm.

It was also significantly greater than LpFg2 on soil forming material and Prior on the

overburden shale. Refer to Figure 12 & 13, for respective histograms illustrating these

differences.

Figure 12. Total mean herbage (dry weight) collected from each group of grass cultivars from the soil forming material. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

68

Figure 13. Total mean herbage (dry weight) collected from each group of grass cultivars from the overburden material. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

69

3.2 Percentage coverage

The Kruskal-Wallis test identified that there was a highly significant difference (P<0.001)

occurring between the grass cultivars (X2 = 40.805, p = 0.000) and a very high variability

accounted by the species groups (refer to Table 2, for individual mean totals). Bn1482 had the

greatest overall ground coverage and was highly significantly greater (P<0.001) than Bf1317

and significantly greater (P<0.05) than LpFg2. Festuloliums, LpFg and LpFm, created the second

and third greatest ground cover, respectively.

The Two Way ANOVA has indicated that there were no significant differences (P> 0.05)

between the percentage coverage, dependent on the materials. Even though the

homogeneity of variance failed, this result has meant that no further analyses were required.

However, the post hoc test revealed that soil forming material provided the greatest coverage

overall and overburden shale produced the least.

70

Table 2. Cultivars mean totals from each investigation.

This data is the raw mean values which was collected from the field subplots and the laboratory experiments Although, this raw data was not used for direct statistical analyse due to large variances, it does highlight the differences and similarities between sets of data.

Cultivars Mean Totals

Aber Dart Aber Magic Bn1482 Bf1317 LpFg LpFg2 LpFm Prior

Cut 1 (g) 92.84 94.32 92.69 80.07 76.36 96.29 76.22 97.78

Cut 2 (g) 96.41 93.01 171.41 88.00 55.89 75.22 73.51 74.22

Cut 3 (g) 132.64 124.92 195.30 76.05 106.83 128.82 146.41 146.24

Cut 4 (g) 133.14 130.37 199.31 80.51 104.41 96.16 112.37 110.43

Cut 5 (g) 43.62 37.98 83.85 48.97 24.62 41.38 24.34 34.36

Total (g) 498.66 480.60 742.56 373.60 368.11 437.86 432.85 463.02

Percentage cover (%) 76.00 73.17 89.17 64.33 83.42 66.83 82.17 77.25

SOM 300c (g) 3.06 3.28 3.13 3.65 3.21 2.97 6.92 2.93

SOM 400c (g) 7.71 8.10 8.60 8.03 8.39 8.20 7.62 7.97

Respiration-

Field moisture (ppm) 3574.58 4329.25 6509.42 4167.08 4177.75 4989.17 7427.25 3869.00

71

Respiration-

Standard moisture

(ppm)

1643.00 1203.25 1912.75 1206.33 2261.08 1470.25 2086.25 1650.50

Root mass (%) 0.43 0.46 0.68 0.36 0.39 0.31 0.30 0.34

72

Table 3.Material mean totals from each investigation.

This data is the raw mean values which was collected from the field subplots and the laboratory experiments. Although this raw data was not used for direct statistical analyse due to large variances, it does highlight the differences and similarities between sets of data.

Soil Material Mean Totals

Weathered Shale Soil Forming Material Overburden Shale Boulder Clay

Cut 1 (g) 90.96 69.18 91.35 101.79

Cut 2 (g) 88.96 120.85 74.27 79.77

Cut 3 (g) 192.29 151.69 79.24 105.38

Cut 4 (g) 112.77 143.63 111.46 115.49

Cut 5 (g) 35.14 55.89 28.21 50.31

Total (g) 520.13 541.24 384.52 452.74

Percentage cover (%) 77.50 80.00 72.00 76.67

SOM 300c (g) 2.74 3.06 5.70 3.08

SOM 400c (g) 8.41 5.57 12.64 5.70

73

Respiration- Field

moisture (ppm) 10088.08

4555.00

1991.21

2887.46

Respiration- Standard

moisture (ppm) 2314.46

1781.33

1547.63

1073.29

Root mass (%) 0.34 0.52 0.34 0.45

74

3.3 Soil Organic Matter (SOM)

The amount of SOM within the subplots was investigated with two different temperatures for

“Loss of Ignition –LOI”. This was due to the soil profile characteristics of the site which included

coal fragments, especially within overburden shale, as identified by the Cranfield reports

(Cranfield, 2015). This section will be divided by the temperature used, 300oC (coal doesn’t

burn) and 400oC (coal burns). The SOM was calculated as a percentage of the soil material

core obtained from each subplot and this was used for the statistical analyses to investigate

SOM differences between subplots and material plots.

3.3.1 Loss of Ignition at 300 oC analyses results

The Two Way ANOVA has indicated that there were no significant differences between the

grass cultivars. Even though the homogeneity of variance failed, this result has meant that no

further analyses were required. However, the post hoc test revealed that Prior provided the

least SOM overall and LpFm produced the most, but these were not significant differences.

The Kruskal-Wallis test identified that there was a significant difference in SOM between the

soil materials (X2 = 14.835, P = 0.002), refer to Table 2, for individual mean totals. The post hoc

test revealed that the overburden material produced the most SOM overall and was

significantly greater (P < 0.05) than weathered shale. Boulder clay produced the second largest

volume of SOM.

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3.3.2 Loss of Ignition at 400 oC analyses

The TWA analysis indicated that there were no significant differences between the grass

species. Even though the homogeneity of variance failed, this result has meant that no further

analyses were required. However, the post hoc test revealed that Bn1482 provided greatest

SOM overall and Aber Dart produced the least.

The Kruskal-Wallis test identified that there was a highly significant difference between the

amount of SOM created between the soil materials (X2 = 79.104, P = 0.000) with a high

variability accounted by the material group, (refer to Table 3, for individual mean totals).

Overburden produced highly significantly (P< 0.001) greater SOM than all other materials.

Weathered shale produced the second largest amount and this was highly significantly

different to the boulder clay and soil forming material, which produced the least.

3.4 Respiration

The following section has investigated respiration of the soil by measuring the CO2 ppm

released from 10g of soil. The experiments firstly analysed the samples in their field moisture

form and then another with additional moisture to optimise conditions for microbial activity.

3.4.1 Natural state sample CO2 analyses

The Two Way ANOVA indicated that there were no significant differences ( P> 0.05) between

the grass cultivars and the CO2 released. Even though the homogeneity of variance failed, this

result has meant that no further analyses were required. However, the post hoc test revealed

that Lpfm provided the greatest CO2 overall and Aber Magic produced the least.


amount of CO2 created between the soil materials (X2 = 26.167, P = 0.000), refer to Table 3,

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for individual mean totals. Weathered shale produced highly significantly (P< 0.001) greater

CO2 than both overburden shale and boulder clay and significantly more (P<0.05) than soil

forming material.

3.4.2 Optimised moisture samples CO2 analyses

With standardised moisture, there was no significant difference between the amount of CO2

released depending on the type of cultivar. However Aber Dart had produced the most CO2

and Bf1317 the least.

The Kruskal-Wallis test identified that there was a significant difference (P< 0.05) between the

amount of CO2 created between the soil materials (X2 = 14.162, P = 0.003), refer to Table 3,

for individual mean totals. Weathered shale again produced the greater amount of CO2, but

this was only significantly greater (P<0.05) than boulder clay.

77

3.5 Root mass

The root mass was calculated as dry root weight within a 20g soil sample obtained from the

subplot.


root mass between species groups (X2 = 26.216, P = 0.000), refer to Table 2, for individual

mean totals. Bn1482 produced the most root dry weight mass according to the post hoc test

and was significantly greater (P < 0.05) than Prior, Aber Dart and Bf1317 and furthermore

highly significantly greater (P<0.001) than two species with the lowest root mass, LpFm and

LpFg2. Bn1482 was the only species significantly different from another species and all the

others were not significantly different from one another. Refer to Figure 14, for an illustration

of these differences.

78

Figure 14. Cultivars’ mean root mass weights and their percentage quantity of the20g soil sample, representing all the materials. All means and standard deviations (SD) have been calculated using the raw data (see Appendix 7.2).

Analyses also found significant differences within the material groups and the percentage of

roots within each material (X2 = 10.234, P = 0.017), refer to Table 3, for individual mean totals.

The post hoc identified the soil forming material as having the greatest total root mass and

was significantly greater (P<0.05) than the worst performing material, weathered shale.

Due to significant effects from both independent factors, further analyses were undertaken

on each material plot, respectively. Bn1482 produced the greatest root weight on all individual

materials, but there were only a significant difference (P<0.05) found within the cultivars on

79

the soil forming material. The post hoc reveal the significance between individual cultivars was

not significantly different. However, Bn1482 was very close to significant value over LpFm (P

= 0.055) and similarly close to significance difference on the weathered shale over Aber Dart

(P = 0.058).

3.6 Root distribution

Due to the characteristics of the site, investigations into deeper depths than 15cm was limited

in the field experiment. The soil pit face was created beside cultivars on the circumference of

the plots. This was only replicated once on each cultivar at best and was not possible for all

cultivars on every plot. Therefore no statistical analysis was felt appropriate for the data

collected. However, the mean results are displayed within Figure 15. The Bn1482 appeared to

be consistently creating the greatest number of roots both above and below 15cm depth.

LpFg2 also appeared to have restrained root development on most materials, especially at

deeper depths.

80

Weathered Shale Soil Forming Material

Overburden Shale Boulder Clay

Figure 15.Cluster bars show the absolute counts of roots and the split of these between the shallow and depth counts. Absolute counts consist of the number of roots that crossed the five lines of measurement: Top - 5, 10 &15cm and Below – 25 & 35 cm. Where information is missing, data was unable to be obtained.

Graphs layout - Top left: weathered shale, Top right: soil forming material, Bottom left: overburden shale, & bottom right: boulder clay.

81

4. DISCUSSION

4.1 Festulolium cultivars will create greater herbage yield and ground coverage compared to

their parental species.

Festulolium’s agronomical value and ecosystem services potential, has been previously

investigated and proven to have significant success on both repects, compared to its parent

species (Humphreys, 2015). The hybridisation of fescue and ryegrass, has created the

opportunity for new cultivars with increased fodder quality, with persistance and resistance

traits, amongst challenging aboitic and biotic conditions (Humphreys, (2011). Whether these

can be applied to an upland reclamation site is unclear in the literature because experiments

have focused typically on rooting potential and fodder within environments with limited

stresses (Humphreys, 2011; Wang and Bughrara, 2005). The desired traits of vegetation on

exposed coal reclamation sites include the ability to establish quickly, tolerate persistant

stresses and create an economic value (Humphreys et al., 2014). Initial investigations on this

site by Chilver (2014) found that the Festuloliums’ yield and percentage coverage was

consistently superior compared to their parental species, especially over the fescue Bn1482.

However, there were variations within the Festuloliums, as LpFg2 and Prior expressed the

highest yields, whereas LpFg created the greatest ground cover. Irregular drought conditions

and limited researched months of growth, has affected the confidence of the results from

Chilver study to represent typical growth of cultivars onsite. For example Bn1482 exhibited

“remarkable growth” within June, highlighting a growth curve which was not fully

investigated.

82

The results from the 2015 study have found conflicting results to Chilver (2014) relating to

yield and percentage ground cover. Contrary to Chilver’s findings, the fescue Bn1482 created

significantly greater ground cover than all culitvars, including the Festuloliums, which is an

alteration from last year’s result where the fescue produced the worst overall percentage

coverage . However, the Festuloliums LpFg and LpFm, still have good ground coverage.This

demonstrates that Bn1482 has spread remarkably throughout its subplots, irrespective of

materials and has been slow to establish (refer to Figure 16).

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Figure 16.Evidence of Bn1482 enhanced herbage and ground cover and the established ground cover of Festuloliums. The photographs were taken on the final cut in August on the best performing material, soil forming material. The Festuloliums poor herbage yield is also evident when compared to Bn1482 (Top left: Bn1482, Top right: LpFm , Bottom left:LpFg2, Bottom right: LpFg ). The red box marks the boundary of each subplot.

Interestingly, this trend continues with the yield produced. Bn1482 consistently produced the

greatest yield in 2015, whereas chilver investigation it typically produced the least herbage

yield. Apart from the initial cut, Bn1482 produced significantly greater yields than both LpFg

and LpFg2 throughout. With the exception of fecue Bf1317, Festuloliums performed the worst

throughout the yields, which was not to be expected. However, they provided a marked

response to the additional fertiliser in May, but these increased yields progressively declined

with time. Both parental ryegrasses typically perfomed better than all Festuloliums

throughout. Interestingly the contrasting performance of percentage coverage and yield

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between Bf1317 and Bn1482, suggested that the Festuca genus was not the conclusive factor,

indicating behaviour traits vary considerbly within the genus, which influences its potential

use for reclamation purposes.

The alteration in the results from this investigation and Chilvers studies could be explained by

depletion of nutrients within the materials. Cultivars of Tall Fescue Festuca arundinacea

have demonstrated frequently throughout literature that genus traits have the ability to

withstrand nutrient imbalances and abiotic stresses, especially in upland areas where land is

especially weathered. Studies within the USA have shown Tall fescues to be slow to establish.

Initially developing extensive root systems and strengthen roots when soils phosphate

concentrations were high but following phospate depletion has maintained the above ground

growth (Fribourg, et al., 2009). By contrast, ryegrasses have an especially high continuous

demand for nitrogen and phosphate for growth but exhibit rapid re-establishment once

nutrients are re-applied (Christians, 2012). Therefore, it is reasonable to speculate that under

these circumstances the Festuloliums would have greater growth than their ryegrass parental

counterparts, due to fescue hybridisation. However, this was not the case and both ryegrasses

had consistently greater yields. The Festuloliums displayed a considerable increase in yield

upon the second application of fertiliser, surpassing both parental ryegrass yields, expressing

a demand for additional nutrients. Moreover, all cultivars expressed an increased yield even

with a decreased growth period (Growth duration - Cut two: 181 days & Cut three: 26 days),

probably as a consequence of both the fertiliser and improved climatic conditions. However,

the Festuloliums had a notable increase compared to the parental cultivars.

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Furthermore, the 2015 study provided an extended overview of the cultivars’ growth amongst

summer climatic conditions. Climatic stress corresponding with behaviour of the cultivars

could have potentially been observed in Chilver’s study if this had been extended for the same

period. In 2015 the ryegrasss and Festuloliums may have been exhibiting supressed growth

due to drought conditions, or expressing a reduced tolerance to abiotic conditions such as the

weathering of material (Hendry & Grime, 2012), therefore, demonstrating that these grasses

had been quick to establish but were struggling for growth under the duration of the site’s

stresses. These stresses could also apply to the Tall fescue Bn1482 improvement, which is a

proven persistent and tolerant grass in upland areas and characterised for its slow

establishment, especially compared to ryegrasses. Therefore the third year of the study has

only now seen its potental vigorous growth that it is known to be able to achieve (Easton, et

al.,1994).

In summary, the Tall fescue Bn1482 consistently provided the greatest yield and percentage

coverage, irrespective of the growth materials. The Festuloliums struggled throughout to

provide yields similar to that of all parental species, except for the period following additional

fertilser. However, they maintained their original ground establishment seen in Chilver’s

study, but on this occasion provided significantly less ground cover than Bn1482.

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4.2 Festulolium cultivars will have a greater root development within material compared

with their parental species.

Reclamation sites regularly have unstable land, due to loss of soil structure and vegetation,

which ultimately directly affects the site’s hydrology, nutrient cycle, stability, moisture

retention and the organisims that rely upon a healthy soil system (Richards et al., 1993).

Therefore the development of rooting systems on reclamation sites is essential, to rehabilitate

these detrimental effects (Li, 2006). Benefits include the ability to create aggregates, enhance

soil structure and filtrate water, which also mitigate against soil erosion and ultimately assist

with vegetation establishment and survival, especially amongst challenging aboitic and biotic

conditions (Humphreys, 2011; Durand et al., 2007). Festuloliums have shown through field

investigations, (especially Prior), to exhibit the fescue trait of enhanced root mass and depth,

when compared to their ryegrass parents, whilst still retaining a productive yield above

ground (Humphreys et al., 2014). Chilver’s (2014) study surprisingly found that Festuloliums’

above ground yields did not correlate with the rooting development below ground, which one

would expect. The greatest root weight was created by the Festulolium LpFg. However LpFg2

was unable to duplicate its above and below ground development and unexpectedly had one

of the lowest root weights. Chilvers’study was unable to fully replicate sampling, which has

provided the opportunity for the 2015 study to investigate the rooting dynamics of the

cultivars further, with greater confidence within the findings.

The investigations of 2015 have found that Bn1482 had in fact replicated its consistent overall

high yield with a high overall root production. Furthermore, results are comparable to the

yield results because all Festuloliums plus the fescue Bf1317 had the least root mass. However,

Lpfg was again the best of the Festuloliums, similar to Chilver study, and LpFg2 and LpFm the

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worst performers. What is clear is that there are still variations throughout within each

cultivar’s results, which meant that there was no significant difference found within each

material except for the worst performing material, weathered shale. Suggesting, further

investigations into the abiotic components of each subplot is required.

Previous research into Prior cultivars have provided significantly greater root mass compared

to ryegrasses within field experiments and consequently has shown potential as a flood

mitigation tool due to its deep rooting. However this was within less challenging abiotic and

biotic conditions (Humphreys, 2011). Moreover, the Festulolium expressed rooting traits

within field experiments of rapid root growth, followed by degradation of roots (Cookson,

2013) and therefore the rooting weight would be significantly less within the third year of this

study. Moreover, the current root mass of the Prior cutivars may not reflect the benefits that

the Priors roots have provided to the retoration of materials. Furthermore, it does highlight

that if the reclamation project requires an extended period of deep rooting grass, not to rely

solely on the Prior cultivar. This is a limitation of both investigations on the Ffos-y-fran site.

The research into rooting dynamics over the three years has been insufficient to conclude the

true root behavours and benefits of all cultivars throughout the field experiment. Deeper root

sampling and water filtration research throughout the experiment, could have provided a

better insight into the cultivars’ root potentials.

Researchers have found that compaction and rock content restrict Ryegrass root growth

(Scholefield and Hall, 1985) which could explain why both culitivars have created less roots

than Bn1482. However, you would expect the Festuloliums to have greater rooting potential.

The lowest rooting mass created by the meadow fescue cultiver Bf1317, may give an

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indication why. Again the Festuca genus rooting potential may vary between cultivars within

these conditions, wheras the tall fescue has naturally hybridised and adapted to upland

habitats and tolerates similar stresses. Possibly the fescue traits that have been hybridized

into the Festuloliums are from fescues that would also be less well adapted to the site’s

stresses and conditions. An additional study, including the the Mediterrean and Atlas fescues

could provide a greater insight into this suggestion. Research by Bughrara (2009) into the

morphology of fescue roots under drought conditions found that the Atlas Fescue reduced its

root mass to improve its survival rate, whereas the Tall fescue cultivar maintained its root

mass during drought conditions. It was suggested that the Atlas fecue cosequently enhanced

its survival on site. Therefore the present root mass results might indicate the current

mitigation protential for erosion and soil structure etc but might not indicate the survival

potential, especially if a site’s stresses increase.

However, there are limitations to the current study’s analyses of root mass due to only

sampling a horizontal core directly through the crown of the grass, therefore only providing

an insight into the concentrations of roots directly below the crown and discounting horizontal

angled roots. The distribution results reveal Bn1482’s rooting system was extensive and

followed the trend of root mass and yield results. Nonethelesss, the root mass results for

Bf1317 and LpFm appear not to have been replicated, having had improved results in the

initial assessments of root distributions (refer to Figure 17 ). Therefore, these initial findings

would suggest a further study would be beneficial into the root characteristics, benefiting

from statistics based on more replicates.

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In sumary, the Tall Fescue Bn1482 produced the greatest root mass through the investigations

into root weight and appeared also to have the greatest root distribution at depths. All

Festuloliums and the Meadow Fescue Bf1317 all recorded poor results for root weight, but

there were no significant differences between these. However, the initial distribution

investigation which utilised miminal soil pits indicated that this might not reflect the true

cultivar’s development underground and will need further investigation.

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Figure 17. The distribution of the roots of Bn1482 (Top left), LpFm (Top right) and LpFm (Bottom left) on the soil forming material. The right circle and arrow indicate the location of the magnified photgraph. It is possible to see the extensive root system of Bn1482 at depths and also LpFm & Bf1317 fine roots at depth, which were also disper

91

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4.3 Festulolium cultivars will create greater SOM and an enhanced microbial activity

Reclamation projects with the objective to rehabilitate soil systems, with a future goal for that

system to be sustainable or which can exist with limited management, need to accumulate

SOM through an active microbial community. These both are seen throughout the literature

as good indicators of the health and recovery of a soil system (Schafer et al., 1979). Frequently

the literature has suggested that microbial activity on reclamation minespoil sites has been

the limiting factor of rehabilitating the nutrient cycle and reclamation success (Visser, et al.,

1984; Williamson & Johnson, 1991). Microbial activity is essential for plant decomposition

into SOM, releasing vital nutrients into the soil system. Furthermore, the symbiotic

relationship of both plants and microbial communities allows plants to take up nitrates and

phosphates. The concentration of SOM can directly and indirectly affect the physical,

biological and chemical composition of the soils (Gerrard, 2003), consequently influencing

vegetation and fauna establishment and survival within the system. Thequantity of SOM and

consequently the SOC affects the amount of this crucial energy source for both microbial

activity and vegetation (Osman, 2013). Moreover, the interaction of these is the determining

factor for the amount of SOC and therefore value of the site to sequestrate carbon as an

ecostsyem service (Ussiri et al., 2006).

Chilver’s (2014) limited investigation into the total SOM on the site, concluded there was no

significant difference in the amount of SOM between each cultivar and materials. Researchers

have found that typically yield volumes correlate with total SOM (Brock, et al., 2011), which

Chilver expected but did not find. However, litter can have limited digestability for microbes

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(Berglund, 2004). Chilver highlighted and also studies by Malik and Scullion (1998) have

suggested that SOM steadily accumulates over time and so it is to be expected that the initial

years are to be minimal within reclamation soils.

The 2015 study incounted similar challenges with the SOM results from the LOI measurements

using 400oC , probably due to the coal content of shale. This was emphasized, when compared

to the SOM result from the 300oC LOI analyses and therefore the findings within that dataset

have limited confidence and were therefore disregarded.

A year on from Chilver study, there is still no significant effect of grasses on SOM. There was

also no significant difference found between the CO2 respired between the cultivars

throughout the field moisture samples and standardised experiments. This is probably due to

the experiment , still being in its early stages of establishment within challening abiotic

conditions. The limited variations of SOM between the cultivars is expected to be the reason

for similar respiration data. However, there was a significant difference between the SOM in

materials, this will be disccused in section 4.4.

Future studies could alternatively investigate the carbon within the herbage and analyse the

comparisons with the SOM. The herbage is likely to have a direct affect on the input of SOM

and carbon into the soil system (Lefroy, et al., 1993), which could provide an indication of

future SOM accumulations. Furthermore, in the interest of carbon sequestration, future

research could also investigate SOM at different depths as well as root depth. Grasses have

varying capacity to sequester carbon at different depths and surface carbon sequestration is

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vulnerable to loss to the atmosphere (Liu, et al., 2012), therefore limiting the grass cultivars

potential as an ecosystem service provider.

In summary, results for the SOM were similar to the Chilver (2014) study and demonstrated

no significant differences between cultivars. This may indicate again that the experimental

plot is in a early stage of establishment and cannot highlight accumulated SOM differences to

a significant level. Therefore at this stage Festuloliums have not enhanced the SOM and

furthermore, did not enhance microbial activity.

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4.4 Materials will differ in their potential for reclamation objectives

The Ffos-y-fran site has limited material for its reclamation project. However four materials

on site are available as a substrate for grassland restoration. The shales within this study have

been extravated from depths and therefore have limited similairities to typical topsoil. The

soil forming material and boulder clay, have greater potential for cutivars to perform better

due to the substrate textures and nutrients present. Chilver study (2014) found the cultivars

growth and percentage ground cover, to be significantly greater on these materials compared

to the shales. Literature has highlighted that materials will degrade on reclamation sites from

weathering (Haigh, 1992), especially clay, which is present in both. Thus, increasing stresses,

including decrease porosity and increased compacton, on cultivars growing on these materials

.

However, the 2015 study has found that the soil forming material to produce the significianty

greater total herbage over only the, overburden shale. There was a consistent trend of the

soil forming material, creating the greatest herbage throughout the cuts except for when

fertiliser was appled. On application, Weathered shale produced significantly more herbage

than all other materials.Furthermore, there is visual evidence of erosion on the boulder clay

material, with the surface of the plot undulating. Some literature suggested that clay materials

used on opencast reclamation sites are susceptable to nutrient depletion after intial

establishment , which inhibit vegetation root growth along with lower porosity (Haigh, 2000b).

However, this would need further investgation to conclude this suggestion.

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The soil forming material apparenty also suported the greatest root mass and was significantly

greater than weathered shale. This was expected, due to the high rock content in both shales

found by Chilver (2014) and limitations that this can cause to root penetration (Clark et al.,

2003). The suggestion of compaction and deterioration of the clay material may also explain

the limited root mass within the boulder clay.

Interestingy, on this occasion there was no significant difference between the cultivars’

percentage cover on all materials. This indicated that three years after establishment, that all

materials have similair potential to create ground cover after three years. Again, this maybe

as a consequnce of nutrient depletion and tolerance of certain cultivars under these stresses.

However, there was a significant difference between the SOM in materials with overburden

shale producing the most. Interestingly, this did not correspond to the respiration data

collected which indicated the opposite, that weathered shale had highly significantly more

microbial activity compared to both overburden shale and boulder clay. Even with

standardised moisture this did not change the trend of CO2 created.

The high SOM content in overburden shale and then the low respiration data, appear to be

conficting results, especially as there should be a positive relationship between the two.

Moreover, the overburden shale produced the least yield and root mass, which then adds

additional doubt into the true SOM results from this material. Furthermore, the SOM results

for the material within the LOI at 400oC highlighted the high proportion of coal fragments

present. Given that coal’s point of ignition can vary depending on its composition, and can be

lower than 300oC (Shen, 2000), its is reasonable to suggest that the SOM results are not

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reliable. Also it has been highlighted in several literature sources that the 300oC temperature

used in this study will only ignite partial SOM within samples, due to incomplete oxidise

organic carbons (Bisutti, et al., 2004; Chatterjee, et al., 2009) and a minimum of 400oC -550oC

is generally required. LOI anlyses has been a rapid, inexpensive method to estimate SOM, but

on this occasion it has had severe limitations (Rahman, et al., 2012; Heiri, et al., 2001).

The high concentrations of CO2 respired within the weathered shale is also an unexpected

result. Due to the extensive storage of materials prior to being utilised within these

experimental plots (Taubman, 2015) and additional weathering, microbial activity would be

expected to be minimal (Barnhisel & Hower, 1997). Furthermore, the weathered shale

produced the least amount of SOM, which highlights the need for further investigation into

these respiration results and the origin of the CO2 being created.

In summary, the soil forming material has again proven to be the best material for

development of the cultivars, with increased yield production and root mass, as expected.

However, after three years of establishment there is no significant difference between the

materials’ effect on the percentage cover of the cultivars. Moreover, there is also no statistical

evidence that there is a difference between the materials’ abilities to affect the SOM created

or volume of microbrial activity. So on the evidence provided, only the soil forming material

has seen a notable effect on the development of the cultivars.

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5. CONCLUSION

This research project has investigated the potential of Festulolium cultivars within the

reclamation of the opencast coal mine site, Ffos-y-fran in South Wales. The cultivars abilities

have been compared to four other parental cultivars within the Festuca and Lolium genera.

Investigations focused on the development of all cultivars, above and below ground, on four

different materials, which represented the available on site material for the reclamation

project. This study followed on from research by Chilver (2014) upon the same experimental

plots and cultivars at Ffos-y-fran. However, this research project investigated the

development of the cultivars in their third year after establishment. Furthermore, research

has been focused on the soil and cultivar interactions within the field experiment.

Findings from this investigation have highlighted that the cultivars’ characteristics on the

experimental site have changed over the year, since Chilver’s research. A key objective of the

reclamation project for Miller Argent is for the site to have a grassland which can provide

commercial value and mitigation to surface erosion post-mining. Initial research from Chilver

concluded that the Festuloliums LpFg2, LpFg and Prior all produced significantly greater

herbage yields compared to all of the parental cultivars. However, contrary to these findings,

this investigation has found the opposite to be the case within the third year of the

experimental plots. In fact, the Fescue Bn1482 consistently provided significantly higher

herbage yields, whereas all of the Festuloliums performed much worse. The higher yield in

both studies was partnered with greater percentage ground cover, illustrating that not one

species would be appropriate for a reclamation site to provide both a productive crop and an

effective mitigation against erosion throughout the three years. Sowing just the LpFg2, LpFg

and Prior Festuloliums could initially create an effective strategy against surface erosion,

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sediment movement and velocity of surface water. Furthermore, it could create a productive

yield to the site, enhancing the aesthetic image of the scared landscape and initiating the

rehabilitation of the soil system. However, by the third year the sward would be considerably

less productive, especially compared to the fescue Bn1482. Under the challenging abiotic and

biotic conditions the cultivar has improved its growth, providing a productive yield and

mitigation against surface erosion. Furthermore, this investigation has provided evidence that

the root system is also extensive, providing structure and potentially benefits such as water

filtration. However, sowing just Bn1482 will leave the site vulnerable to erosion, extend the

period that the land appears degraded atheistically and risks the potential for gullying.

Furthermore, evidence has suggested the Bn1482 cultivar to have produced the greatest root

mass within the top fifteen centimetres of soil in the third year. Initial evidence suggests this

to be the case at deeper depths but this needs further investigations. Without this evidence,

the cultivar’s potential to aid water filtration, soil accumulation and structure is still unclear.

Evidence has highlighted the potential to sow a seed mix containing all four cultivars, LpFg.

LpFg2, Prior and Bn1482. This would provide greater confidence to the reclamation

management that the site will have an effective grassland in place to mitigate against erosion,

improving aesthetics, and can also provide a commercial value. The grassland would be able

to establish and survive, with low management inputs and limited fertiliser on the Ffos-y-fran

site. Evidence has also suggested that the topsoil with the greatest potential for these

objectives with these four cultivars would be the soil forming material. Furthermore, these

suggestions can be given with confidence but only on the evidence provided within the initial

three years establishment of the experimental plots. The cultivars suggested and material

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behaviour henceforth, is an unknown quantity and a longer study is suggested to gain further

knowledge.

Research has been unable to find conclusive evidence of any cultivar affecting the SOM or

microbial activity on site. It is important to note that these are essential for a site’s full

rehabilitation, which will include low input management and the objective to be sustainable.

Furthermore, without further investigations into the cultivars’ rooting systems, the

investigation is unable to suggest with confidence which cultivar would have the greatest

potential for carbon sequestration.

5.1 Recommendations

This section describes the improvements which could be applied to this investigation if it were

replicated.

1. Conduct rooting investigations throughout the study, extracting soil cores within

wetter months, at deeper depths, in more locations, including surrounding and

through the crown of each cultivar. Focusing on root mass and SOM/SOC.

2. Analysing the carbon content within herbage to investigate potential SOM/SOC

accumulations.

3. Investigate the nutrient composition and acidity within the fourth year, within each

material and subplots.

4. The microbial community’s rates of decomposition and the digestibility of herbage is

also an unknown.

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5.2 Future Research

Collective evidence has thus far been un-conclusive on the Festulolium rooting development

and the soil/plant interaction is still relatively unclear. An extended field experiment, including

the parental, Atlas and Mediterranean fescue , and an additional laboratory investigation

would aid this gap in knowledge.

It would also be beneficial to conduct research into the potential of a mixed sward, including

the cultivars, sown at different rates of seed and analyses of the composition development of

that sward. This could also include legumes to enhance nitrogen fixation.

Investigations could also include analyses of larger soil fauna communities, such as

earthworms, due to their being an integral component of the nutrient and carbon cycles.

Finally, the filtration and retention of water is a crucial aspect of the grassland as a reclamation

tool, but has yet be tested and could provide a greater confidence of Festuloliums and other

cultivars’ potential for flood mitigation at the Ffos-y-fran site and other mining reclamation

sites in Wales.

The results from this investigation are not conclusive. Therefore caution and additional

research is advised.

Word count: 15,226

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