Schnittgutabfuhr oder Gründüngung? Auswirkung der Kleegras-Nutzung auf Nitrat im Sickerwasser und Folgefrüchte

Summary

A field experiment was conducted to evaluate the impact of different management systems of grass-clover (various cutting and/or mulching combinations) and date of ploughing (autumn or spring) on the fate of nitrogen (N) and the yield of succeeding wheat. The 3-cut system resulted in nitrate losses below the limit of the EC Nitrate Directive (91/676/EEC), even with ploughing in autumn. When ploughed in spring, treatments with frequent cutting and/or mulching induced nitrate leaching below the critical value. In contrast, losses from swards mulched only once were considerably above the threshold value, independently of ploughing time. With swards mulched and ploughed in autumn, nitrate concentrations exceed the EC-limit. The management of grass-clover swards did not affect the yield of wheat, whereas ploughing in autumn increased the yield. It is concluded, that appropriate grass-clover management and date of ploughing can reduce N-leaching, even in stockless farms.