soil compaction research - british grassland society for fwag... · soil compaction •70% of...
TRANSCRIPT
Soil compaction research
Soil Compaction • 70% of grassland soils in England and Wales
exhibit signs of compaction
Research Partnership
Grassland, forage and soils 20 Research Projects:
Grass
Alternative forages
Soil
Out-wintering
Economics
BGS working with
DairyCo launched the
DEMO FARMS in
2013 to demonstrate
research in practice
Background research
• Deliberately compacted medium soils at Dumfries site in 2011
• Compaction created by both trampling and trafficking
Bulk density & Water retention
• Compaction increased
soil water retention by
c. 17%
• Compaction increased
bulk density
• Most of the increase
caused by the first event
First cut yield
• Both tractor and livestock induced compaction reduced first
cut yield
• Average reduction under trampling = 14%
• Average reduction under trafficking = 22%
Nitrous Oxide losses • Compaction alters soil microbial activity
• Increased emissions of nitrous oxide (N2O)
• Reduced nutrients available to grass N2O losses following March
fertiliser application were
14.9g/ha/day more from tractor
compacted soils and 7.4g/ha/day
from trampled sites compared to the
non-compacted control
Influence of aeration
Bulk density
Influence of aeration
Influence of aeration
Research findings summary
• Compaction is easily caused and identified
• Average first cut yield loss of 14% form trampled and 22% form tractor compaction
• 30% higher N2O emissions from tractor compaction
• Both slitting and sward-lifting reduce bulk density in both types of compacted soil
• More data is needed to understand the influence of aerators on yield
Crathorne Farms, Yarm • Soil lifting and spiking
• Controlled Ttfficking
Ray Brown, Holmes
Chapel • Soil lifting and spiking
• Utilising slurry on gazed grass
Home Farm, Newton St
Cyres • Separated slurry utilisation
• Spike aeration
Chynoweth, Truro • Lucerne as a sustainable
source of home-grown
protein
Trink, St Ives • Surface aeration
• Out-wintering replacement
heifers
Holmes Chapel
Spike = 3.8% yield increase
Lift = 13% yield increase
Combined spike in spring & lift in autumn =
15.1% yield increase
Graze – Silage – Graze – Graze , 2013 & 2014
Demo includes:
1. No aeration
2. Spike aerate only (spring)
3. Spike aerate (spring)
and sward lift (autumn)
4. Sward lift only (autumn)
Quickes Home Farm
7.4 litres more
milk per day
from grass from
the spiked site
Sward-lift
Soil map
Trink • Comparison of two types of surface aerator
• Comparison between spring and autumn aeration
• What was the effect of each on grass growth
• What was the effect of each on herbage quality
A
B
2014 yield results
A = 3.5 % better than B and
5.8% better than no action
Summary
• Demo Farm trials are incomplete and ongoing
• Site specific and farm specific
• Limited control of other influencing factors
• Nevertheless some food for thought:
– Even light soils compact
– Both types of mechanical aeration can improve soil structure and yields
– Sward-lifting + spiking OR aerating in the spring and autumn further increases yields
– But take care with timing!
Events 2015