EFFECTS OF DIFFERENT SPECIES AS GREEN MAN URE ON YIELD AND PROCEEDS OF THE SUBSEQUENT CROPS

In three years of field trials and under three different climatic cond itions (''dry'', ''wet'', ''rough''), the effects of different legumes as under- and stubble-seed and of non-legumes only as stubble seed, w ere tested on the yield and proceeds of the subsequent crop. The highe st yield surplus compared with the respective untreated plot was reach ed with underseeds. In the rather dry area alfalfa (+20 % yield of the subsequent crop) was most effective, under humid conditions (+30 %) a nd under rough climatic conditions (+40 %) white or red clover. Stubbl e seeds had much lower positive effects. In the case of cruciferae the yield surplus of the subsequent crop ranged between 3 and 12 %. The e conomic proceeds (after deduction of the expenses for seed, soil culti vation etc.) were only very slightly positive with alfalfa (dry climat e), but highly positive with red and white clover (humid and rough cli mate). The nitrogen effect in these trials was about 90 kg N/ha with a lfalfa under dry climatic conditions and about 60 kg N/ha with red or white clover under wet or rough climatic conditions. The influence of legumes on the yield of the covercrop was generally low, only on one s ite yield losses of the covercrop were observed, when Persian clover w as grown as underseed. Under more humid or rough climatic conditions r ed or white clover can be recommended as underseed. With these green m anures financial advantages can be expected. Under rather dry climatic conditions alfalfa as underseed has positive yield effects in the sub sequent crop, but in the short term no financial advantages.