Abstract
Succeeding summer crops (upland rice, sweet potato, peanut and millet) were cultivated on soils where preceding winter crops (naked barley, wheat, rape and common vetch) had been done on. A better growth of upland rice tended to be recognized when following common vetch than rape, less when following naked barley and wheat than other crops, but no distinct tendencies on yields of rice were recognized, peanut being so. Better growth of sweet potato and millet was recognized when following common vetch than other crops, viz. the order being as follows : common vetch>rape>naked barley>wheat. Sweet potato and millet following common vetch showed the highest yield in these plots. The soil that common vetch had been cultivated on contained more aggregate than the soil that wheat and naked barley had been done on, but after the harvest of succeeding crops this fact in soil structure was not recognized. Common vetch and rape had good influence on succeeding crops, and sweet potato and millet remarkably were influenced by preceding crops. So it is suitable to combine preceding crops that have good influence on succeeding crops with the latter that remarkably are influenced by the former.
