Studies on the Irrigation and the Deep Plowing : I. On the growth and yields of upland rice and soybean plants

Abstract

The growth and yields of upland rice and soybean plants affected by irrigation, deep plowing, heavy manuring and these assorted treatments were investigated, 1955∼1958, at the Kikyogahara Experiment farm. The results were summarized as follows: 1) The influences of these treatments, on the heading or flowering and maturity, were not so remarkable. But only the maturity of soybean plants was delayed by irrigation when heavy rainfall in the late growing season and hastened by irrigation when low rain fall in the season. 2) The roots of upland rice and soybean plants were lengthened by deep plowing and heavy manuring, and shortened by irrigation. 3) 0n the upland rice plants, genarally, each of these treatments increased length of culm and ear, number of ears, percentage of ripend grains and weight of 1OOO grains. On the soybean plants, each of these treatments increased length of stem, total number of nods, fertile pods and fertile grains per plant. Especially, the irrigation was most effective. In these treatments, the effects of a treatment were more remarkable by using together with other treatments. 4) Accordingly, it was recognized that there was interaction among these treatments on the yields of upland rice and soybean plants. The effects of irrigation and deep plowing on soybean plants were not so striking as those of upland rice plants