1) In order to know the relation between rice plant and forage crops in the paddy fields, we have studied the suitability of cropping systems by planting several forage crops before and after the rice plants with some shifting in planting. 2) We have made four classifications on rice planting; such as very early, early, usual and late. 3) Barnyard grass, sudan grass, corn, cow pea, sunflower and sweet potato were suitable as the first crops to be planted after harvesting of the very early rice planting. Chinese milk-vetch and transplanted or direct sown rape were suitable as the second crops. 4) Rape, oat, turnip and radish were suitble as the first crops after harvesting of early rice planting. As for the second crops, wheat, rye, oat and leguminous crops such as Chinese milk-vetch and vetch over the winter were suitable. 5) Chinese milk-vetch, common vetch and hairy vetch sown among standing rice plants were suitable for usual rice planting. Growth of oat sown after plowing on the paddy field was especially good. 6) Oat and transplanted rape were suitable after harvesting the late rice planting. Harvest was greater when soybean and corn were sown mixed in April. 7) "Late rice planting+forage crops" was the best cropping system with the view of Total Digestive Nutrient. "Early rice planting+forage crops" and "very early rice planting+forage crops" were better than "usual rice planting+forage crops".
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