アルファルファの生理的特性に関する研究 : 第2報 NPK 施肥レベルがアルファルファの生育ならびに収量におよぼす影響

抄録

The experiment was performed from 1962 through 1963 to clarify the effects the N, P and K fertilization level would have on the growth and yield of alfalfa. In this experiment in which pots were used, 4 plots (nil (0), low (1), control (2) and high (3) plots) were provided for each of N, P and K supplied. The plants were cut 10 times in al during the test period, namely, 4 times in the first year of experiment and 6 times in its second year. The results obtained are summarized as follows: (1) The effect on the plant height was especially remarkable in the case of N and P fertilization level, and was less evident when K fertilization level was applied. The influence of P was evident in the first year, and the plant height was especially small in the P₀ plot. On the other hand, remarkable effects of N were observed with regard to the plants subjected to 1st and 2nd cuts in the second year. As a matter of fact, the plant height was smaller in the N 0 plot, and this effect was particularly evident in the N3 plot to which a relatively large amount of N was supplied. (2) The number of plant stems increased as the number of cuts went up. The effect in question was most evident in the case of N fertilization level, and P fertilization level and K fertilization level followed in that order. The number of stems increased with the rise of the amount of N supplied, and so this tendency was most eviden in the N3 plot. With regard to the effect observed in the P fertilization level plots, the number of stems decreased in the P 0 plot, and no remarkable difference was observed among the stem numbers in the P1, P2 and P3 plots. With the increase in the amount of K supplied, the number of stems tended to go up bit by bit, but the difference among the stem numbers of the different levels was not significant. (3) The hay yield was most severely influenced by the amount of P supplied, and the yield in the P 0 plot was lowest of all the 12 plots. The effect of N on the hay yield was noticeable in the first year but in the second year, no significant difference was observed between the yields in question so far as N fertilization level was concerned. In contrast, K fertilization level had no effect on the hay yield in the first year, but had noticeable effects in the second year. (4) In view of the dry matter producing rate in forced draught oven at 70°C, the amount of dry matter produced did not necessarily decrease even during the high-temperature period.