Tillage’s direct impacts on the soil

duration of looseness

Influencing factors: a) tillage process,

b) tillage quality (resulted loosened or

non-loosened state), c) soil quality

(e.g. sensitivity to settling), d) climate,

d) modes of tillage followed loosening

process

So: some months / 1 or more seasons

Bad example: soil may

resettle by surface tillage

operations

non-loosened state

Tillage’s direct impacts on the soil

depth of the loosened layer

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

Dep

th o

f ro

ot

zo

ne (

cm

)

shallow adequate good very good

= depth of root zone

Rooting depths (cm) of

crops in experimental

conditions (Hatvan, 2002-2013)

Legend:

A: average season,

D: dry season,

R: rainy season

..it may either help

or hinder the

development of the

roots of plants of a

particular species

-55

-45

-35

-25

-15

-5

No

pa

n

Plo

ug

h

pa

n

No

pa

n

Se

ed

be

d

pa

n

No

pa

n

Dis

k p

an

No

pa

n

Dis

kp

an

Maize Sunflower W. mustard W. wheat

Ro

oti

ng

dep

th (

cm

)

Average season

Dry season

Wet season

-35

-30

-25

-20

-15

-10

-5

0

0 1 2 3 4 5 6

Penetration resistance MPaD

ep

th c

m

loosen

diskpan

Soil in a loosened state and

deteriorated by disk pan

-40

-35

-30

-25

-20

-15

-10

-5

0

0 1 2 3 4 5

Penetration resistance MPa

Dep

th c

m

loosen

ploughpan

Severe:

> 3.0 MPa

Soil in a loosened state and

deteriorated by plough pan

Location of subsoil

compaction

Examination periods

1.

1976-1987

2.

1988-

1990

3.

1991-

1997

4.

1998-

2001

5.

2002-

2007

6.

2008-

2010

Percentage of observed area

below 60 cm 14 4 1 0 11 9

below 40 cm 22 12 6 2 21 26

at the depth of 28-32 cm 44 47 42 36 30 34

at the depth of 22-26 cm 14 22 23 14 21 16

at the depth of 18-22 cm 6 10 16 22 12 10

2 c. layer below 16 cm 0 3 7 14 5 5

3 c. layer below 16 cm 0 2 5 12 0 0

Examined area (ha) 2420 2860 2580 1860 4690 2870

Subsoil compaction observed on 17,280 ha of land during

six examination periods in Hungary (1976-2010)

Occurrence and extension of the compacted layer

La-

yer

cm

Below

40-45 cm

To a depth of

30-35 cm

To a depth of

20-25 cm

To a depth

of 15-20 cm

From the toplayer

(e.g. 0-45 cm)

Location of

the

compacted

layer

5

10

15

20

25

30

35

40

45

50

Stressor Nature Ploughing Disking Traffic

Climate stress poor poor-moderate moderate strong very strong

Tillage’s direct impacts on the soil

Ranking of extension:

0-10 mm compact layer: slight

10-30 mm: medium

30-50 mm: heavy

50-100 mm: severe damage

Tillage’s direct impacts on the soil

agronomical structure (aggregation)

proportion of dust (<0.25 mm), small crumbs (0.25-2.5mm), crumbs (2.5-10

mm), and clods ( >10 mm )

A soil with a 70-80 % crumb fraction

has a good structure, while a soil

with a higher than 50 % dusts has a

poor structure.

The trend of crumb forming is affected

by tillage, the crop sequence and the

degree of surface protection

Growing crumb fraction is a result of

carbon and moisture conserving tillage

and of effective surface protection

Originally well-structured

soils have been pulverised by excessive

tillage

dust small crumbs

clod crumb

Soil crumbling improvement and maintenance

(Hatvan, 2002 – 2013)

Hatvan, 2002 – 2013; P: ploughing + levelling, L: loosening, SC,C: cultivator use,

D: disking, DD: direct drilling

40

50

60

70

80

90

100

2002

M

2003

W

2004

R, P

2005

W, M

2006

W, F

2007

C

2008

S

2009

W, M

2010

C

2011

O

2012

W

2013

SB

Cru

mb

(0.2

5-1

0 m

m)

%

P L SC C D DD

beginning

of trial

wide row

crops

wide

row

crop

M: Mustard

W: W. wheat

R: Rye

P: Pea (green)

C: Corn

S: Sunflower

O: Oat

SB: Spring barley

surface form

Tillage’s direct impacts on the soil

100 % (flat), 200-300 % (rough, cloddy)

Tillage treatment Surface

forming

Soil moisture

loss

Climate-induced

damage after sowing

in late summer

Deep ploughing yes medium medium

no great heavy

Deep loosening yes medium medium

no great heavy

Mulch in surface yes little little

Relationships between summer tillage and the likely climate risks

it should be minimised to reduce

loss of water in any season and

particularly important in the summer

months

water is lost through the large

surface of a dry cloddy soil

surface area may be enlarged in a

wet season

A large surface is acceptable in wet soil condition, but…

Tillage’s direct impacts on the soil

surface cover

Soil surface is exposed to weather and farming impacts:

Soil structure damages, it turns into silt by rain, it dries and later on crust

forms; it dries and perhaps even blows away by wind

Protection may good or inadequate during the growing season,

depending on the crop cover; Dense crops and grasses give better

protection.

Soil needs particular protection during the critical periods, especially in

the summer after harvest and in the spring after sowing.

In summer the chopped crop residues should be spread on the soil

surface for protection.

The advantages of surface cover out of growing season: reduced soil moisture loss,

protection of the top-layer against climate-induced damage,

maintaining / encouraging favourable biological activity,

improving soil workability.

Surface protection

by cover during

critical periods

Cases Cover rate (%) and protection

GOOD MEDIUM POOR

Following harvest 55 – 65 35 – 45 < 10

Stubble tillage (summer) 45 – 55 35 – 45 < 10

Primary tillage (summer) 25 – 35 15 – 25 0 – 5

Primary tillage (winter) 15 – 25 10 – 15 0

Between wide rows (hot spring days) 15 – 25 10 – 15 0

Risk low moderate great

accepted by practice

great risk

100 %

35-45%

<10 %

15% 25% 45-50%

Surface cover

non-recommended

Water transport

Tillage’s indirect impacts on the soil

The proportion of precipitation actually

ends up in the soil: 70-80 % in favourable

cases, but often it is around 65-70 %.

Tillage improves soil water intake

capacity but it may increase its water loss

Water intake and storage depend on the

depth of the loosened layer and the

permeability of the soil below disturbed

layer

Balance between

intake, storage and

loss

water-loss increasing surface

water conserving surface

150

170

190

210

230

250

270

290

310

330

07 26 08 08 08 23 09 05 09 19 10 21

Wate

r co

nte

nt

mm

/0-6

0 c

m

ST0 ST25 ST50 ST100 PD

CDR PL PLL PPD

LSD0.05: cover: 3.022; tillage: 6.118

0mm 12mm 60mm27mm 26mm

Soil moisture trend at different stubble treatment during 85 days

(Hatvan, July-Oct. 2013)

Legend ST0: stubble, no cover

ST25, 50, 100:

covered stubble

PD: used plate disk

(6-10 cm)

CDR: conventional

disk + roll (10-14 cm)

PL: ploughed

PLL: ploughed and

levelled

PDP: ploughed, and

prepared by plate

disk

Outside the growing season the extent of water loss is affected by the

shape of the tilled surface, surface cover and the depth of

disturbance.

precipitation

Long-term land use

– water loss or water conserving

water utilization of plants

soil tillage

(water loss or water conserving)

soil condition

- capability of intake and

storage;

- capability to transport from

deeper layers to the root zone

Independent of farming

1) Precipitation (input)

2) Soil water management (

)

Depends on farming

Water conservation or loss

Water content for workability in a Chernozem soil

at Hatvan

-65

-60

-55

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 5 10 15 20 25 30 35 40

Soil moisture (m/m%)

De

pth

(c

m)

Lower limit

Upper limit

Loosening

Ploughing

Tine tillage: between upper

and lower layer

Water content levels (m-3m-3) related to soil tillage

(forest/loamy soil)

< 13 14 – 17 18 – 21 21 – 24 24 – 28 > 29

Wilting point:

9.42 – 10.34

Optimum

(21 – 22)

Dry Moderately

dry

Humid Wet Over-wet

Solid state Semi-solid state Plastic state

Clod/dust,

forming

Clod/crumb

forming

moderately

Crumb forming Structure

deterioration

Smearing,

puddling

Soil

disturbance

non-

recommended

Good for

subsoiling,

disking

Good for ploughing

and levelling, tine,

surface preparing,

sowing

Trafficable, but

soil may be

damaged

Tine tillage?

Direct drilling?

Non-trafficable,

non-workable

(non

ploughable)

More energy,

more damage

Least energy, least

damage

Most energy,

most damage

Water that cannot seep into the soil will

never be utilised by crops!

.

Precipitation mm > water seeping into the soil

Bad soil state = less stored water + greater loss

We have to identify the real cause of the water-logging

(natural or human / farming induced)

farming-induced

water-logging

0

200

400

600

800

1000

1200

1400

1600

PL 28-

32 cm

L 35-40

cm

D 16-20

cm

D 12-14

cm

C 16-20

cm

C 12-14

cm

SBP SW DD

C f

lux k

g h

a-1

90 d

ays

-1

max

min

LSD5%: min:58, max:109

C content of straw + root: 3000 kg ha -1

The possible C-loss of soil at

minimised tilled surface

under 90 days, in a moderately

dry season

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

PL 28-32

cm

L 35-40

cm

D 16-20

cm

D 12-14

cm

C 16-20

cm

C 12-14

cm

SBP SW

C f

lux k

g h

a-1

90 d

ays

-1

max

min

C content of straw + root: 3000 kg ha-1

LSD5%: min:143, max:196 kg

The possible C-loss of soil

leaving relatively large surface

under 90 days, in a moderately

dry season

Legend:

PL: ploughing, L: loosening,

D: disking, C: tine tillage,

SBP: seedbed preparation,

SW: sowing, DD: direct drilling

Tillage’s indirect impacts on soil state – CO2 release

Carbon balance in case of maize following w. wheat

C input t/ha Bad tillage C output

t/ha/season

Good tillage C output

t/ha/season

Straw 5.0 Stubble tillage

(inadequate) 0.59 – 0.64 Stubble tillage

(appropriate) 0.33 – 0.41

C content of straw 2.0 Weedy stubble 0.02 – 0.06 Chemical weed

control 0.02 – 0.06

Roots 2.5 Ploughing 22-25

cm, non

prepared

2.58 – 2.63 Ploughing 22-25

cm + preparation 0.86-1.07

C content of roots 1.0 Preparation by

disk + roll 0.32 – 0.39 Cross-board

levelling + roll 0.007 – 0.009

Seedbed

preparation

1x/2x + sowing

0,054 – 0,092 Seedbed

preparation,

sowing, in a day!

0.036 – 0.039

Other traffic 0.152 – 0.323 Other traffic 0.152 – 0.323

Total C input 3.0 C loss 3.716 – 4.135 C loss 1.405 – 1.911

Balance - 0.72 / - 1.14 +1.60 / +1.09

Risk Moderate

C reduction

C and humus

increase

Roots + stubble stub 1.55

C content of stub 0.62

Balance - 3.10 / - 3.52 - 0.79 / - 1.29

Risk Great

C reduction

Moderate

C reduction