Platforms to test and demonstrate sustainable soil management: integration of major UK field experiments

Abstract

Three long term and one newer soil management experiments from eastern Britain were used to answer several key questions relevant for cereal growers. The questions focused on soil physical and chemical conditions (including possible carbon accumulation) for crop growth and comparing cultivar, yield and economic performance under different tillage regimes. To respond to these questions, a number of approaches to characterise soil quality were used, particularly in ways relevant to root proliferation. 

Based on our results, non-inversion yields were lower than inversion yields but there were no differences between the three inversion tillage treatments. With promotion of, and movement to, reduced (non-inversion) tillage in the UK this suggests a need for breeding programs to consider crop performance under soil conditions created by non-inversion (or no-till) systems. 

No strong reason for not advocating reduced (non-inversion) tillage in preference to ploughing was found. In the experiments using farm-scale machinery, yield data under non-inversion tillage was only marginally lower than under ploughed conditions but when decreased costs of labour and fuel were factored in, gross margins under non-inversion tillage were better than under ploughed systems. The hesitation from advocating non-inversion tillage more strongly comes from the plot-scale experiment which ran with no crop rotation (for more than 10 years) and developed severe weed problems. Under these conditions, ploughing helped control weeds and thus delivered better productivity.    

Using a range of indexes, our study, consistent with other research, found soil physical condition was well below optimal at the sites studied and in many instances offered very limited opportunity for root proliferation. In soils under non-inversion tillage, we sometimes found large improvements to soil physical conditions over a growing season driven by the growing crop. Under no-till, the pH of the surface soil decreased to an extent where it would contribute to further soil structural deterioration and limit plant productivity. Whether changing soil tillage regimes can alter the total amount of carbon (as organic matter) stored in soil is of wide interest. We assessed carbon storage over the soil profile to a depth of 60cm and took account of bulk density and stone content. We found no gains in carbon storage under non-inversion tillage (compared with ploughed systems). Where there were large annual additions of carbon as compost, the amount of carbon stored in the soil was increased.