巣まきは収量を高めうるか

抄録

In 1946,LYSENKO stressed the importance of hill-planting in agricultural practice, and stated that Kok-saghyz (Taraxacum kok-saghyz RODIN) plant produced several times more yield of root when planted in hills than when the same amount of seed was evenly distributed over the field. Much has so far been said of the advantage of hill-planting by Japanese investigators, but there are as yet little evidences that may lead・to a rea・sonable conclusion. Two experiments were carried out in 1954 and 1955 with radish and soybean to investigate the effect of hill-planting and the number of plants per hill on the yield of these crops (Figs. 1 and 2). The results showed that the yield per area (y) was solely determined by the plant density or the number of plants per area (ρ) whether they were grown singly or in hills of various sizes. So far as the density remained constant, the plants always yielded approximately the same amount of crops per area as given by the Yield-Density Effect formula, yρ^<α-1>=K (KIRA et al. 1953), irrespective of the mode of planting. It was suggested that the plants closely standing together in a hill may have the advantage over isolated individuals in their resistibility to certain unfavorable conditions such as the severe competition with weeds. This may result in higher per cent survival of initially planted individuals which in turn may increase the final yield.