Fertilizer Response in Cultivated and Wild Soybeans

Abstract

In soybean there is meager information on response to fertilizer application among different species. Therefore, three experiments were conducted using cultivated soybean, Glycine max (L.) Merrill cv. Akisengoku and wild soybean, G. soja Sieb. et Zucc., K-01 line. The objectives of the investigation are i) to determine the response to the application of N, P, K and Ca under three soil types, namely, sandy soil, upland field soil and paddy field soil (Exp. 1) and ii) to understand the response to nitrogen application in paddy field soil (Exp. 2 and 3). The following results were obtained. 1) Effect of major nutrient application on the vegetative growthes and seed yields of cultivated and wild soybeans varied with soil types. The fertilizer responses were dramatic in sandy soil, slight in upland field soil and paddy field soil especially on K-01 line although their vegetative growthes were much better than in sandy soil (Table 3, 4). 2) When harvest indices (HI) (seed yield/total top dry weight) were compared, both species had low HI in sandy soil which had very little nutrients. In upland field soil and paddy field soil HI were high and HI of Akisengoku was higher than that of K-01 line. When each total top dry weight of K-01 line and Akisengoku was more than 40 and 80 g/plant, respectively, HI in both species began to decline (Fig. 1). 3) Akisengoku had better vegetative growth response to nitrogen application at early growth stage, but no relation was recognized at flowering stage. Regardless of growth stages K-01 line showed very little or no response (Table 5). 4) The effect of nitrogen application on the seed yield and yield components of Akisengoku was not significant. Yield and yield components decreased in K-01 line in the highest nitrogen treatment. However, in the other treatments no such decrease was observed (Table 8). 5) Nitrogen application inhibited the nodulation at early growth stage in both species. The degree of inhibition was much greater in K-01 line than in Akisengoku. At later growth stage the nodulation of Akisengoku in nitrogen treatments was comparable to no nitrogen treatment. But the nodulation of K-01 line in the highest nitrogen treatment was not good, compared with the other treatments. Therefore, the seed yield of K-01 line in the highest nitrogen treatment decreased (Table 6, 8).