Effects of catch crops on silage maize (Zea mays L.): yield, nitrogen uptake efficiency and losses

Abstract

Under the climatic conditions of north-western Europe, silage maize (Zea mays L.) production optimized with respect to nitrogen (N) fertilization and crop rotation is required to reduce N losses. Whether winter catch crops (CC) can serve as a beneficial biological tool in terms of N-loss abatement as well as maize yield also under optimized N management, is unclear. Therefore, a 2-year field experiment was conducted to study the short-term effects of a continuous maize-catch cropping system on maize yield performance, N2O emission and N leaching, as affected by maize harvest/CC sowing date (10, 20, 30 September and 15 October, respectively, hd1–hd4) and CC species (rye, Secale cereale L. and Italian ryegrass, Lolium multiflorum Lam.). Treatments without CC served as control and N fertilization was applied as synthetic N to better adjust to maize N demand. The CC treatment (with or without) had no effect on maize dry matter and N yields, but the N uptake efficiency of maize responded significantly to the N accumulation (Ntot) of CC. Nitrate leaching mostly stayed below the critical load value for EU drinking water and rye significantly reduced nitrate leaching, given that environmental conditions allowed sufficiently high CC biomass accumulation. Annual nitrous oxide emission was unaffected by CC treatment. Restricted N fertilization of maize following CC led to N deficiency, since CC decomposition obviously was not synchronized with maize N demand. Under the given environmental conditions, rye may serve as beneficial CC in continuous maize cropping even in already optimized N management.