Restoring soil quality through re-integration of leys and sheep into arable rotations

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The economic and environmental sustainability of UK arable farming is facing a crisis, caused in part by soil degradation as a result of continuous intensive cultivation. The use of ploughing and short rotations in which a small number of crops (especially wheat and oilseed rape) are grown with very high frequency with high reliance on inputs of fertilizers, pesticides, herbicides has led to loss of soil organic matter, compaction, reduced water-storage capacity and increased risks of water pollution from soil erosion and agro-chemicals, and reduced farm profitability. This has been compounded by the build-up of increasingly intractable herbicide- resistant weeds in wheat such as blackgrass, and pesticide- resistant insects such as flea beetle in oilseed rape in these short rotations. To address these problems, some farmers are starting to return to mixed farming, reintroducing leys containing grass and clover, grazed by sheep, into arable rotations hoping this will improve soil quality, reduce weeds and diseases and boost profits, but without the critical evidence they need to guide these decisions. Our multidisciplinary proposal directly addresses this industry-led research need. We recognize the urgent requirement to determine how best to restore soil quality, and achieve good livestock production and economic returns through a comprehensive evaluation of the costs and benefits of such systems. Our goal is to provide the first comprehensive industry-informed, farmer-participatory assessment of soil quality, environmental and economic cost-benefits, farmer motivations and barriers to reintroducing sheep into arable rotations, focused on our most intensively cultivated areas of eastern England. Our approach is to compare traditional grazed grass-clover leys and conventional crop cultivation, with innovative management systems that hold the promise of better returns involving combining novel species-rich herbal leys, mowing and no-tillage direct drilling of the crops. The work is divided into five work packages.1.Farmer-participatory research network: We are building a network of arable farmers who are already conducting initial trials into introducing grass-clover and species-rich herbal leys, sheep and no- tillage, into arable rotations. We will run workshops with participant farmers, as well as those who have not made these changes, and conduct a large-scale farmer-survey to understand the motivations for, and barriers to, incorporating these alternative systems. We will identify where farmers have had success with these approaches and what has made them successful. 2.Soil quality restoration and sheep production: We will set up field experiments with a participatory group of farmers to compare the effects of herb-rich leys with traditional grass-clover leys under sheep grazing versus mowing, on soil quality, (organic matter, structure, effects on water storage and infiltration, nutrient cycling, earthworms and organisms associated with sheep faeces. We will assess sheep production (live weight gain, and intestinal pathogens) and the biomass production of the leys. 3 Effects of reducing tillage: Determine whether direct drilling offers benefits over disc or plough-based tillage on subsequent arable crop production and soil quality following leys (including assessment of yield, nutrient use efficiency, weeds, diseases and pests) in our participatory farm-based trials.4 Farm-scale cost-benefit analysis: Evaluate the environmental and economic cost-benefits of bringing sheep and grass-clover versus herbal leys into arable rotations, mowing, and use of direct drilling compared to current arable tillage practices - assessing the costs and output values to farms, and nutrient use efficiency of the different approaches. 5 Upscaling and policy implications: Landscape-scale effects including impacts on flood and pollution risk and consider targeted farm payments to encourage the most beneficial practices