Farmers must address ‘twin drivers’ of compaction
Soil compaction costs the UK around £400-500m every year, cutting wheat yields by 10-15%, increasing tillage energy, time and costs by up to 300% and reducing soil infiltration to almost zero, significantly increasing run-off and flooding.
This was the harsh, economic reality highlighted by Dick Godwin of Harper Adams University at the recent Soil & Water Management Centre Day from a 2011 Cranfield report for DEFRA.
Estimating that arable farming is responsible for 70% of these costs, he set out a number of things growers can do to save themselves and the country at large this major wastage by addressing the twin drivers of compaction – vehicle loading and pressure.
“There are a number of things growers can do to reduce the main causes of compaction by better choice and use of tyres and tracks,” he insisted. “They are not without their cost. But this is small compared to the economic benefits they can give.
LOOSE SOILS
Growers must also be aware that soils that are too loose can be highly problematic, warned Harper Adams soil scientist, Nigel Hall.
“Apart from having less soil material for roots to exploit, soils holding excessive amounts of either water or air have a very poor load-bearing capacity,” he explained.
“This can lead to serious trafficking difficulties and rutting, not to mention sheet and gully erosion. Looser is not always better.”
“For instance, the £1/ha that using the latest Ultraflex tyre technology is calculated to add to the annual tractor bill more than offset by fuel savings of around 20% and reductions in working time, let alone soil damage. Equally the £3-4/ha cost of tracks on a combine over a five to seven year life is offset by improvements in trafficability, harvest timing and harvesting efficiency.
“Studies show both low ground pressure systems and Controlled Traffic Farming (CTF) can increase typical wheat yields by 1.3-1.7t/ha. And reducing the area of land exposed to traffic through CTF has particular extra benefits in improved soil structure and reduced operating costs.”
While prevention is always better than cure, Prof Godwin also pointed out there are plenty of ways for growers to alleviate compaction. He stressed there is a real advantage to both winged sub-soiling tines and leading shallow tines, urging particular care with both equipment set-up and traffic on freshly loosened soil.
