Studies on the successive cropping of root vegetables (I)

Abstract

The experiments were made to know the influ-ence of successive cropping to the growth of taro, edible burdock, carrot and Japanese radish. (1) Taro causes a severe damage by its successive cropping. The growth and the yield remark-ably decrease after 2 years of its successive crop-ping. The deficiency of the exchangeable cal-cium and the increase of the exchangeable acidity are some of the causes of the damage by the successive cropping, but other causes are not yet known. (2) Edible burdock is also severe in the damage by its successive cropping. In this case, the main cause seems to be the damage by nematodes in the soil. (3) Carrot ordinarily causes no damage by its successive cropping, but rather improves its quality. Nevertheless, the increase of nematodes in the soil prevents its successive cropping. (4) Japanese radish causes no damage by its successive cropping at all. The length and the growth of the root are rather developed by its successive cropping for about 10 years.