Effects Of Different Planting Methods Of Winter Green Manure On Production Efficiency,Nutrient Utilization And Soil Fertility In Paddy Field

Field experiment and lab analysis were carried out to study the nutrient accumulation of five leguminous green manure crops, Chinese milk vetch(CMV; Astragalus sinicus L.), hairy vetch(HV; Vicia villosa Roth.), smooth vetch(Vicia villosa Roth.Var.), common vetch(CV; Vicia sativa L.) and broad bean(BB; Vicia faba L.), and the application effects of these green manure crops on rice yield, nutrient absorption and soil fertility. Moreover, the effects of CMV intercropped with oilseed rape on comprehensive benefits of paddy-upland rotation were investigated to examine the feasibility of oilseed rape intercropped with Chinese milk vetch in paddy-upland rotation. The main results are as follows:(1) The nutrient content and accumulation in leguminous green manure crops were measured after 180 d and 200 d of sowing, respectively. The fresh yield and N, P, K accumulation of SV and CMV was relatively high and two years average fresh yield was in the range of 17938 kg/hm2 to 21179 kg/hm2. However, the fresh yield of HV, CV and BB was comparatively low, with the average fresh yield of 14025-14496 kg/hm2.(2) The incorporation of green manure crops with 70% chemical fertilizer did not reduce the rice yield compared with CF(100% chemical fertilizer). The rice yield of SV+F70 was the highest and increased by 3.1% compared with CF. But the rice yield of SV+F70, HV+F70, CV+F70 and BB+F70 was higher than CMV+F70, and increased by 1.4-6.9%. The use of HV, SV, CV and BB as green manure have the same effect instead of using chemical fertilizer compared with CMV during winter fallow in Hubei province.(3) Incorporating green manure crops into field can decrease the demand of chemical fertilizer by 30% without affecting the soil fertility, compared to CF. Instead, the incorporation of green manure crops considerably increased the nitrogen content in rice grains and nutrient use efficiency.(4) Four years of green manure cropping(CMV,HV,SV,CV and BB)along with 70% chemical fertilizer improved the soil organic matter by 0.5-8.0%, compared with CF.(5) Comparing with mono-cropping, Rape(R) and CMV intercropping did not decrease the grain yields of rape as well as rice, and recorded the higher annual economic benefits in rape-rice rotation. The two years average income in R/CMV intercropping treatment was increased by 478.5 Yuan/hm2 over R, 3978.5 Yuan/hm2 over CMV and 5593 Yuan/hm2 over CF treatment.(6) Rape intercropping with Chinese milk vetch improved the organic matter,total nitrogen and available phosphorus content by 2.4%, 12.1% and 12.1% compared to CF and 8.6%, 6.2% and 8.6% compared to R, respectively. In crux, these results suggested that R/CMV intercropping can raise the soil fertility and improve the sustainable production capacity of paddy fields.