Ermittlung der Vorfruchtwirkung unterschiedlicher Wintererbsengenotypen in Rein- und Gemengesaat

Summary

In organic farming the cultivation of leguminous crops is one of the most important sources of nitrogen (N). However, in the case of winter field peas, the amount of N fixed, N supply to the subsequent crop and N balance there are hardly any published data. Therefore, the pre-crop effect of six genotypes of winter pea (five regular leaf type, one semi-leafless cultivar) and one semi-leafless spring pea cultivar in single and mixed cropping (with rye spring barley respectively) was examined in three suc-cesive growing seasons (2003/04-2005/06). Immediately after harvest, a catch crop was sown and sampled during the first half of October to determine biomass dry matter and N uptake.
In single cropping, N uptake by the catch crop was usually significantly higher after regular leaf type peas in two years, whereas in mixed cropping it was only in one (p<0.05). It is suggested that response of N uptake was - among other possible factors (like e.g. soil tillage after harvest) – due to the mineralized N content in soil at harvest as both correlated significantly (R² between 0.53* and 0.79***, with exception of semi-leafless winter pea (R²=0,19)). It is very important to protect the large N quantities after conventional leafed winter pea cultivars as a sole crop against leaching. Results for the third experimental season will be presented at the conference.