Embed Size (px)
Citation preview
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
