A research point of view: How to improve ecosystem services provided by

agricultural soils

Eila TurtolaMTT Agrifood Research Finland

Photo: Visa Nuutinen, MTT

• Agricultural soils as source of ecosystem services for water quality

• Examples how soil functioning can be improved by management inside or outside the field

• Time-scales of beneficial changes

• Provide photosynthesis: Food, feed, etc. • Habitat for soil biota • Act as buffer and transformer: water evaporation and storage

(hydrological cycle), nutrient turnover and storage (nutrient cycles of C, N, P) > regulation of nutrient input to waters

• In Finland with >5 mill. people and present diet, ecosystem services of agricultural soils are markedly smaller than those of forest soils: Agricultural soils cover 7% of land area but are responsible for 50-60% of anthropogenic load of N and P to waters

However, how much could we improve the ecosystem services of agricultural soils in terms of better water quality? Can we reach the water quality targets and when? What is sustainable for the soils themselves?

Agricultural soils

How to improve soil’s functions and achieve good water qualityFor the first, we should strive for conditions prevailing in native soils:

1) Improve water infiltration (prevent surface runoff > decrease erosive forces, provide oxygen for plant roots > increase crop yields)

= subsurface drainage, increased earthworm density

2) Add more organic shelter on the soil surface (decrease erosive forces)

= direct drilling/perennial crops

3) Lay smaller stress on soil’s buffering capacity against nutrient inputs

= tight nutrient cycles

1a) Erosion: Good subsurface drainageof clay soils, short and long-term

In a heavy clay soil under cereals with autumn ploughing, reduction in 10 years: 46% Turtola et al. 2010

+For barley yield,increase of 18% followed by a reduction in N balance from 45 to 23 kg/ha

Poor drainage: 2120 kg/haGood drainage: 1140 kg/ha

Figure: Jari Hyväluoma, MTT

1b) Erosion, multifunctional biological activity: Long-term potential for natural soil drainage

Photo: Risto Seppälä, Visa Nuutinen, MTT

0 10 20 30

Ploughing No-till No-tillPloughing

metres

Plot margin Field margin

Subdrainposition

= Inoculation point

= Sampling point 2009

and

Inoculation of Lumbricus terrestris in 1996Nuutinen & Butt 2010

Photo: Risto Seppälä, Figure: Visa Nuutinen, MTT

Potential for increased population in 15 years Nuutinen & Butt 2010

Indi

vidu

als

m-2

0

10

20

30

40

50

60

70

1996 1998 2003 2010 1996 1998 2003 2010

Margin Field(the constantly unploughed parts)

Year

Figure: Visa Nuutinen, MTT

Combined benefits from reduced tillageNuutinen & Butt 2010

Indi

vidu

als

m-2

0

10

20

30

40

Plough No-till

Fres

h m

ass

g m

-2

0

10

20

30

40

Plough No-till

Density Mass

Figure: Visa Nuutinen, MTT

..and from subsurface drains Nuutinen & Butt 2010

Distance from inoculation (m)

Field: Above subdrain Field: Between subdrains

5 22 39 56 9 28 43 60

Indi

vidu

als

m-2

0

10

20

30

40

50

60

5-922

-2839

-43 56

-60

Margin

Figure: Visa Nuutinen, MTT

2) Soil erosion and N:Permanent grasscover (set-aside), effective when present

In a heavy clay soil, compared to cereal cultivation with autumn ploughing,reduction in 5 years: 75% in erosion 85% in N leaching Turtola et al. 2010

~ The grass values represent potential minimum loads of soil erosion and N for this soil? Long-term effects of grass in crop rotation?

Ploughed: 1140 kg/ha5-year grass: 280 kg/ha

Ploughed: 13.7 kg/ha5-year grass: 2.0 kg/ha

Figures: Jari Hyväluoma, MTT

3) DRP: Tight P cycle, target in the long term

In South-West Finland, the potential effect in 20 years: 40% reduction in DRP losses Lemola et al. 2009

> The potential minimum load of DRP due to tight P cycle is still less

Figures: Riitta Lemola, MTT

DR

P l

oad

, g

/h

a

Year

Year

P use, South-West Finland

DRP load, South-West Finland

Manure P

Need of P

P use 2005

For the second, complementary, intensive methods rely on different amendments for fields and field edges

• Gypsum• FeSO4

• Fe-Ca oxide granules

Photos: Risto Uusitalo, Aaro Närvänen, Eila Turtola, MTT

0.4 m colloids, pH 6 Salt concentration on the left 0.3 mmol/l, on the right 25 mmol/l EC approximately 10 S/cm and 1000 S/cm, respectively

Picture: Jari Hyväluoma, MTT

To achieve good water quality • To improve functions of agricultural soils, we need site-specific,

long-term management plans. There is evidence that consistent actions are acknowledged in 10-30 years with:

up to 50% lower erosion from clay soils (hydrological management for less surface runoff and more favourable pore structure in subsoil, strong biological activity)30-40% lower DRP losses (tight P cycle)

• Immediate DRP and erosion reductions may be possible using ’first-aid’ measures at selected hot-spot sites

• We should not forget that higher crop yields/ha and/or change of our diets would enable less soil use for agriculture > more for nature

”Ecosystem services are the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life”(Daily 1997)

20-35 cm:n syvyydessäKsat Makrohuokosten tilavuusosuus

35-55 cm:n syvyydessäKsatMakrohuokosten tilavuusosuus

Pintavalunnan osuus(nurmella)

1989 20012v. ennen 10v. jälkeen

0.69 cm/h 1.89 cm/h

0.39 % 0.67 %

0.005 cm/h 0.10 cm/h

0.017 % 0.30 %

67 % 35 %

(75%) (54%)

Huonosti toimivan salaojituksen uusimisen (v. 1991) vaikutus savimaan rakenteeseen

Eila Turtola 2006

N-lannoitus kg/ha

Sato kg/haN jyvissä kg/haN-tase kg/haN-huuhtouma kg/ha

Ennen Jälkeen

100 91

3 680 4 350 55 68 45 23 8.1 9.9

Vaikutus ohran satoon ja typen huuhtoutumiseen(syysmuokkauksena kyntö, kaikki ruudut 1980-1999)

Eila Turtola 2006

Irtoaminen

Eroosio: maan pintarakenne, kasvipeitteisyys ja valunta

pintavalunta 50%eroosio 1000 kg/ha

ojituskuntoon

monivuotinenviherkesanto

eitiivistetä

pintavalunta 5%eroosio 500 kg/ha

ojitustaei paranneta ei nurmea

ajomärällämaalla pintavalunta 95%

eroosio 3000 kg/ha

salaojakaivannotjuurikanavaverkosto

lierokanavat

nyt 30 vuoden kuluttua

kestävä pintarakenne

Eila Turtola 2001