Studies on the Acceleration of the Early Crowth of Upland Crops : I. Influences of the fertilizer and the soil moisture contents upon the early crowth of upland rice plants

Abstract

In orber to increase the yield of crops in the cooler region of Japan (Tohoku), it is important to accelerate the early growth. The purpose of the present study is to find out how to accelerate the growth of the upland rice plants. The relationships between the kind and amount of fertilizer and early growth were studied in the controlled climatic chambers (about 16.5°C). On the other hand, the effect of soil moisture on the growth was observed in a glass room. The results are summarized as follows: 1. The influence of the amount of fertilizer upon the early growth of upland rice plants being at the about third leaf stage was obviously recongnized. That is, the absorption of nutrients and the growth of plants increased in proportion to the amount of fertilizer (the maximum in this experiment was 2.0 g N, 4.0 g P2O5 and 2.0 g K2O per 1/5000 a pot). 2. The degrees of acceleration of the early growth was maximal from nitrogen and decreased in the order phosphorus, pottasium, among the three elements of fertilizers. 3. In the case of the soil moisture content over 50 % of the maximum water holding capacity (120 % of dried soil), germination, growth and absorption of nutrients were scarecely affected by the soil moisture. But these decreased in proportion to soil moisture below 50%. Moreover, the effect of fertilizer was obviously observed in the former. But in the latter case, both germination and growth tend to be fallen with the increase of fertilizer.