If you can’t optimise soil structure you could do more to select varieties better suited to farm conditions, suggested Paul Hallett, head of sustainable production systems at The James Hutton Institute.
In trials comparing zero-tillage, min-til discing to 5-7cm depth, ploughing to 20cm followed by cultivations, ploughing followed by artificial compaction and deep ploughing to 40cm, a wide range of spring and winter barleys showed a big variation in ability to cope with soil conditions.
“Really interestingly, under intensive husbandry, Fighter in particular did best under high disturbance and worst under low soil disturbance,” he said at the Crop World conference.
Could genetic variations in root formation, and even production of exudates, enhance soil penetration? Trials are under way to evaluate that.
Can tillage help sequester more carbon in Scotland? “In parts of the world it seems to work quite well, but it looks like it is just lazy data collection,” Dr Hallett commented. In the top soil layer min-til and conventional tillage can achieve higher carbon levels, but poorer deep rooting means overall sequestration is no greater. Furthermore, seasonal weather variations over-rode any cultivation effects.
Preserving soil condition and recovering it once degraded is not easy. “Soils and their aggregate formation, which support agriculture, are created by geological and biological processes over many, many years,” noted Prof Banwart, project leader of the EU SoilTrEC project, which aims to pinpoint the key processes involved.