抄録
This study was carried out to ascertain the effect of winter forage crops on the growth of succeeding summer crops. The results were as follows; 1) Both under standard and much fertilized conditions, Italian ryegrass, serradella and turnip gave high yields. 2) Red clover was superior in forage yield in much fertilized condition, and provided a good cutting yield in late spring. 3) Italian ryegrass, red clover and serradella were not the favourable previous crops to early paddy and upland rice, because their forage yields were reduced due to early cutting. 4) Recommendable previous crops to early paddy and upland rice were turnip and rape. Oats and oats-vetch mixtures which are relatively high in early cutting yield, were also favourable. 5) 80 to 90% of residual root weight of each crop remained within 15cm of soil from the surface. Residual root weight was the highest in Italian rye grass and the lowest in serradella and turnip. The similar results were obtained from root system investigation. 6) The ratios in weight of root to above ground part were 30-50% in oats, Italian ryegrass and oats-vetch mixtures, 20-40% in commen vetch, serradella and red clover, and 20-50% in turnip and rape. 7) Ploughing and harrowing were difficult in the field on which Italian ryegrass and red clover were grown, due to the much branched rooting of the former and the deep rooting of the latter.
