Growth Traits of Adzuki Bean and Rice Bean Grown in Phosphate Deficient Soil

Abstract

Rice bean and local adzuki bean variety (swidden adzuki) used to be cultivated in low fertile soil under swidden conditions in Shiiba village, Miyazaki, Japan. These beans might have some ability to absorb minerals from the low fertile soil. To clarify N and P absorption ability of these two beans, these beans were cultivated in pots applying N, P, or no fertilizer, using soil at 22-month after burning. Modern adzuki bean variety, ‘Dainagon’, was also cultivated for comparison. Numbers of leaf increased with N and P fertilizer and P fertilizer postponed leaf aging. Number of flower was not affected by fertilizer and yield increased with P fertilizer. Numbers of flower and yield of the rice bean were more than those of the two adzuki varieties. Leaf N content increased with N fertilizer and leaf P content increased with P fertilizer. Leaf P contents in the rice bean and swidden adzuki were higher than that in Dainagon. Moreover, leaf P contents in the rice bean and swidden adzuki without fertilizer were higher than that in Dainagon with P fertilizer. With Truog method, available phosphate in the soil after cultivation did not differ by varieties, but with Bray 2 method, that in the rice bean was lower than those in the two adzuki varieties. Thus, the rice bean and swidden adzuki are suggested to have high P absorption ability. Especially, the rice bean was found to absorb P from Al- and Fe-P.