soil management for grass growth manage… · soil management for grass growth dr george fisher ....

Soil Management for Grass GrowthGrass Growth

Dr George Fisher

Topics

• What is a ‘healthy’ soil?

• Soil structure• Soil structure

• pH, P and K

• Soil compaction (assessment and removal)

• Protecting water quality

Topics

Topics

Topics

Soil quality matters

• because:

Profitability comes from maximising your opportunity to grow

and use grass and forage

• That means:

4,500 – 5,000 litres milk per cow per year from grass and forage

700 kg liveweight gain/ha/year from grass and forage

Med

Hig

h

Net m

arg

in (pence p

er lit

re)

Reducing costs increases profitLow

Net m

arg

in (pence p

er lit

re)

Low Med High

Cost of production (pence per litre)

The cost of energyFeed Cost per t

DMEnergy content

(MJ ME/kg DM)

Energy cost per 5.4 MJ

Milk value(litres/kg

DM))

Grazed grass

£35 12.0 1.6p 2.2

1st cut silage £65 11.5 3.1p 2.13rd cut silage £120 10.5 6.2p 1.93rd cut silage £120 10.5 6.2p 1.9Wheat £160 13.6 6.4p 2.5Barley £150 13.2 6.1p 2.4High energy conc.

£265 14.0 10.2p 2.6

Medium energy conc.

£250 12.5 10.8p 2.3

Topics

• What is a ‘healthy’ soil?

• Soil structure• Soil structure

• pH, P and K

• Soil compaction (assessment and removal)

• Protecting water quality

Liming and productivity

• It means:

- Nutrient use efficiency (N and P)- Nutrient use efficiency (N and P)- Cost reduction (feeds and fertilisers)- Minimising risks to the environment

It’s a win/win/win/win – just take it!

70

80

90

100

% o

f m

axim

um

DM

yie

ld

Grass

Soil pH and grass/clover growth

30

40

50

60

3 4 5 6 7

% o

f m

axim

um

DM

yie

ld

Soil pH

Grass/White clover

From Hopkins et al. (1990) Grass and Forage Science

Impact of 5 t/ha lime dependent on soil structure

0.5

0.6

0.7

0.8R

ise in

pH

(u

nit

s)

0

0.1

0.2

0.3

0.4

2 2.5 3 3.5 4 4.5 5

Ris

e in

pH

(u

nit

s)

Soil structural quality (Sq)

Sq 2.6

Sq 4.5

Impact of 5 t/ha lime dependent on soil structure

0.5

0.6

0.7

0.8R

ise in

pH

(u

nit

s)

More compacted

Less compacted

0

0.1

0.2

0.3

0.4

2 2.5 3 3.5 4 4.5 5

Ris

e in

pH

(u

nit

s)

Soil structural quality (Sq)

More compacted

The pH status of soils on grassland farms

�Professional Agricultural Analysis group (PAAG)(180,000 soil samples)(180,000 soil samples)

�NRM Ltd.(11,000 soil samples from grassland)

Soil pH – The state of play in

UK grassland soils

20

25

30

35

40

% o

f sam

ple

s

0

5

10

15

20

% o

f sam

ple

s

Soil pH

PAAG 2010/11

NRM 2010/11

Soil pH – The state of play in

UK grassland soils

20

25

30

35

40

% o

f sam

ple

s

• 5 – 30% DM yield loss?• Reduced NPK efficiency?• Increased risk of N/P loss?

0

5

10

15

20

% o

f sam

ple

s

Soil pH

PAAG 2010/11

NRM 2010/11

Phosphorus (P) and Potassium (K)

� P for rooting and growth� K for N uptake and water

How are your indexes?

Percentage of grass soil samples in P and K indices

P INDEX

K INDEX < target target > target

< target 20 12 10

target 10 8 8

> target 7 9 15

(PAAG, 2012 – 38,266 samples)

Conclusion

Topics

• What is a ‘healthy’ soil?

• Soil structure• Soil structure

• pH, P and K

• Soil compaction (assessment and removal)

• Protecting water quality

Soil pH is basic…

Soil structure is fundamental

British Grassland Society, Unit 32C, Stoneleigh Deer

Park, Stareton, Kenilworth, Warkwickshire, CV8 2LY

LIFT IT SPIKE IT

Assessing the impact of compaction

Treatments:

1. Control – no traffic

2. Tractor compaction

3. Trampling compaction3. Trampling compaction

No treatment Sward lifted Spike aerated

Offtakes 2013

5

6

7

8k

g g

rass

DM

/ha

No Treatment

+4%

+11%

0

1

2

3

4

kg

gra

ss D

M/h

a

No Treatment

Spike

Lift

Lift and Spike

3000

4000

5000

6000

Offtake

Grazing 2 Grazing 3

Grazing 1

SilageOfftakes 2014

0

1000

2000 Residual

Offtake totals

Control – 5840

Spiked – 6021 (+3%)

Lifted – 6607 (+13%)

S&L – 6648 (+14%)

Soil compaction – reasons to be interested

Soil compaction reduces grass DM yield by 15%

Non-compacted

• 12 t DM/ha/yr grown

Compacted

• 10.2 t DM/ha/yr grown• 12 t DM/ha/yr grown

• 80% utilised = 9.6 t DM /ha

• 10.2 t DM/ha/yr grown

• 70% utilised = 7.14 t DM /ha

2.46 t DM/ha/yr @ 11 MJ ME/kg DM = 27,060 MJ ME

� £585/ha to replace in concentrates (£248/t)� £1,252/ha from 5,000 litres milk @ 25ppl

Topics

• What is a ‘healthy’ soil?

• Soil structure• Soil structure

• pH, P and K

• Soil compaction (assessment and removal)

• Protecting water quality

Courtesy of The Environment Agency

Courtesy of The Environment Agency

Courtesy of Reaseheath College

Courtesy of Reaseheath College

Think about:- Source- Path- Receptor

Courtesy of Reaseheath College

- Receptor

Courtesy of Reaseheath College

Courtesy of Reaseheath College

Courtesy of Reaseheath College

Courtesy of Reaseheath College

Thanks for your attention

George Fisher ConsultingGeorge Fisher Consulting

37, Portland Drive

Scholar Green

Congleton

Cheshire

ST7 3BS

07598 964388

g.fisher99@btinternet.com