Little fertilizer response but high N loss risk of maize on a productive organic-sandy soil

Information on the environmental impact of maize production is actually inconsistent. Indeed some experiments report good nitrogen (N) efficiencies and small residual N. Other experiments show large leaching losses, while in practice maize production is often coupled with an intensive production and large N surpluses. Here, we present data from a 4-year experiment with silage maize on a sandy soil of high mineralization potential. The experimental set-up included three N input forms, mineral, cattle and pig slurry and four rates of total N, of 0, 80, 160 and 240 kg N ha−1 year−1 and the use of suction cups. Results show that dry matter and N yields for N0–N240 were relatively high and consistent (158–192 kg N ha−1). Further findings show large residual soil mineral nitrogen, of 138–237 kg N ha−1, and high nitrate concentrations in leaching water during winter, of 39–73 mg NO3–N L−1, corresponding to leaching losses of 86–152 kg N ha−1. Response to N input was small with apparent N recoveries of 14–22% for manures and mineral fertilizers. We conclude that caution is needed when maize production is extended to fields with an apparently high potential for mineralization and that use as grassland would be a better alternative with regard to N leaching losses.