Effect of Turnover of Chinese Milk Vetch(Astragalus sinicus L.)Straws in Three Consecutive Years on Fertility of Soil and Yield of Rice on Paddy Fields in Fujian

By turning over the straws of Chinese milk vetch (Astragalus sinicus L.) after rice harvest to the paddy fields in Fujian in three consecutive years, the effects of the organic farming practice on the soil fertility and rice productivity were studied.The result showed that, as compared with the control, the organic matters in the soil increased by 15.8% on average when the straws were turned over at a rate of approximately 22 500kg·hm-2 per year.And, the bulk density of the soil declined by 8.7%.Both of the above reached significant difference.Furthermore, the total N, P, K, effective P and available K in the soil increased by 18.4%, 16.7%, 9.5%, 19.7%and 70.5%, respectively.In comparison with the chemical fertilization, a significant 6.8%increase on the rice output from the straw-turnover was realized from the gains in panicle and grains per panicle.Consequently, the practice could be promoted in the province to benefit the fertility of the soil as well as the productivity of the rice.