Einfluss des Saatzeitpunktes legumer Zwischenfrüchte auf Ertrag der Deck- und Folgefrucht

Summary

For stockless organic farming cultivation of leguminous cover crops is an important source for the nitrogen supply of organic cropping systems. However, too strongly developing living mulch systems may affect the undersown cash crop. At two experimental sites in Bavaria the impact of the sowing date of cover crops on grain yield of the undersown cash crop winter rye and the subsequent crop spring oat was determined in two and three field trials, respectively (2003/04/05 until 2004/05/06 and 2002/03/04 until 2004/05/06, respectively). Living mulch treatments were white clover and grass-clover (alfalfa, red and white clover, diverse grasses) with seeding in autumn and spring as well as red clover and black medick with seeding only in autumn. Additionally, a control (rye without cover crop) and a legume stubble seed were grown.
The impact of cover crops’ sowing date was crucial to cash crop and subsequent crop. Undersowings in autumn (above all grass clover mixture), but not in spring negatively affected the grain yield of the undersown rye. On average 26 % higher yields of the subsequent crop in comparison to the control were determined after legume in pure stands regardless of sowing date, whereas the grain yield was just increased by on average 7 % after stubble seed. Hence, undersowing clover in pure stands in spring is especially suitable for achieving high yields in following crops.
The impact of cover crops’ sowing date was crucial to cash crop and subsequent crop. Undersowings in autumn (above all grass clover mixture), but not in spring negatively affected the grain yield of the undersown rye. On average 26 % higher yields of the subsequent crop in comparison to the control were determined after legume in pure stands regardless of sowing date, whereas the grain yield was just increased by on average 7 % after stubble seed. Hence, undersowing clover in pure stands in spring is especially suitable for achieving high yields in following crops.