Diversifying cropping sequence reduces nitrogen leaching risks

Overuse of chemical fertiliser in cereal cropping systems has resulted severe degradation air and water quality. Diversifying sequence with legumes provides a natural source nitrogen (N), but also increases N leaching risks after their growing period. Here, we hypothesize that other break crops, i.e., crops grown to diversify the sequence, reduce at rotation scale due contribution increasing nutrient use efficiency crop recovery following crops. In two 4-year experiments conducted northern France, monitored agronomic performance changes soil mineral content field six preceding crop-current combinations including winter wheat (Triticum aestivum), pea (Pisum sativum L.) oilseed rape (Brassica napus L.). We quantified each as function water-fluxes model based on content, climate data characteristics. then simulated scale, for 20 years conditions various management systems. show or reduced harvest cereals (up mean values −28 −19 kg ha−1 respectively), during compared wheat-wheat sequence. Although was higher cultivated, cumulative losses over four experimental sequences were not significantly than no-break sequences. Over years, pea, rape, volunteers catch by up 40 % monoculture. Our study confirms only depends current is affected crop. A large potential reduction could be achieved many intensive cereal-growing regions very limited diversity.