In trials in Orel province, Russia, in 1986-89, catch crops of spring rape were sown immediately after harvesting of winter wheat and barley crops in the following rotations: (1) vetch + oat mixture - winter wheat - barley - oats; (2) peas - winter wheat - maize - barley; (3) clover - winter wheat - potatoes - barley - oats undersown with clover; and (4) fallow - winter wheat - potatoes - buckwheat - barley. The rape was harvested for fodder or ploughed in as a green manure prior to the subsequent crop being sown. Green matter yields of 16-23.4 t/ha were obtained from the rape depending on sowing date and weather conditions. Results showed that after rape was harvested for fodder, yields of subsequent crops were reduced, significantly so in some cases (by 12% for the vetch + oats mixture, by 9.5% for potatoes and by 8.1% for silage maize). However, if the rape was ploughed in as a green manure, the yield of subsequent crops increased; for example, by 8.8% in barley, 9.7% in maize and 10.5% in peas. In terms of fodder units produced per ha, in all cases rape as a catch crop increased values by 7.4-18.9% when harvested for fodder and by 3.8-6.5% when ploughed in.
