The response of Astragalus sinicus L. (Chinese milk vetch) to lime and inoculation

Abstract

An experiment utilizing two varieties (Taiwan and Japan) of Astragalus sinicus, to test their potencial as a green manure crop for the winter periods between crops of paddy rice, was conduced in the rice experiment area of the Estação Experimental Theodureto de Camargo of the Instituto Agronômico de Campinas. Because of the highly specialized nature of Astragalus in regard to high calcium status and high rhizobial strain specificity, the trial was conducted with and without liming and with three variations of inoculation: 1) no inoculation, 2) peat culture inoculation and 3) inoculation with the addition of a pellet of CaCO₃, using gum arabic as adhesive. Growth of Astragalus sinicus was not good on this acid soil even with added fertilizer and lime, although these treatments did increase yield. Nodulation was absent without inoculation. Nodulation by the peat culture method varied from 21 to 60 percent, with the higher figures ocurring under lime treatment. The best treatment was pelleting and liming with a high of 86 percent of the plants nodulated. In general, it would seem that Astragalus sinicus is unlikely to be of much use on very acid rice soils. The trial demonstrated very satisfactorily the benefit to be gained with specialized legumes from the simple process of lime pelleting the seed after inoculation.