Assessing the farm-scale impacts of cover crops and non-inversion tillage regimes on nutrient losses from an arable catchment

Cooper, Richard J., Hama-Aziz, Zanist, Hiscock, Kevin M., Lovett, Andrew A., Dugdale, Steve J., Sünnenberg, Gisela, Noble, Lister, Beamish, James and Hovesen, Poul (2017) Assessing the farm-scale impacts of cover crops and non-inversion tillage regimes on nutrient losses from an arable catchment. Agriculture, Ecosystems and Environment, 237. pp. 181-193. ISSN 0167-8809

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Abstract

The efficacy of cover crops and non-inversion tillage regimes at minimising farm-scale nutrient losses were assessed across a large, commercial arable farm in Norfolk, UK. The trial area, covering 143 ha, was split into three blocks: winter fallow with mouldboard ploughing (Block J); shallow non-inversion tillage with a winter oilseed radish (Raphanus sativus) cover crop (Block P); and direct drilling with a winter oilseed radish cover crop (Block L). Soil, water and vegetation chemistry across the trial area were monitored over the 2012/13 (pre-trial), 2013/14 (cover crops and non-inversion tillage) and 2014/15 (non-inversion tillage only) farm years. Results revealed oilseed radish reduced nitrate (NO3¬¬-N) leaching losses in soil water by 75–97% relative to the fallow block, but had no impact upon phosphorus (P) losses. Corresponding reductions in riverine NO3¬¬-N concentrations were not observed, despite the trial area covering 20% of the catchment. Mean soil NO3¬¬-N concentrations were reduced by ~77% at 60–90 cm depth beneath the cover crop, highlighting the ability of deep rooting oilseed radish to scavenge nutrients from deep within the soil profile. Alone, direct drilling and shallow non-inversion tillage were ineffective at reducing soil water NO3¬¬-N and P concentrations relative to conventional ploughing. Applying starter fertiliser to the cover crop increased radish biomass and nitrogen (N) uptake, but resulted in net N accumulation within the soil. There was negligible difference between the gross margins of direct drilling (£731 ha-1) and shallow non-inversion tillage (£758 ha-1) with a cover crop and conventional ploughing with fallow (£745 ha-1), demonstrating farm productivity can be maintained whilst mitigating diffuse pollution. The results presented here support the wider adoption of winter oilseed radish cover crops to reduce NO3¬¬-N leaching losses in arable systems, but caution that it may take several years before catchment-scale impacts downstream are detected.

Item Type: Article
Uncontrolled Keywords: mitigation,agriculture,nitrate,phosphorus,conservation tillage,river
Faculty \ School: Faculty of Science > School of Environmental Sciences
Related URLs:
Depositing User: Pure Connector
Date Deposited: 05 Jan 2017 00:02
Last Modified: 22 Jul 2020 01:17
URI: https://ueaeprints.uea.ac.uk/id/eprint/61911
DOI: 10.1016/j.agee.2016.12.034

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