稻秆与紫云英联合还田提高黄泥田氮素利用率和土壤肥力

[目的]稻秆与紫云英为南方稻田培肥的重要有机肥源.研究福建黄泥田稻秆、紫云英联合还田与化肥不同比例配施对水稻产量、养分吸收利用及土壤肥力的影响,旨在为该区域中低产田改良培肥及化肥替代提供依据.[方法]开展连续4年的田间定位试验,在等氮投入条件下,设置稻秆、紫云英联合还田与化肥不同配比6个处理,稻秆与紫云英二者氮素投入总...

Combined returning of milk vetch and rice straw improves fertilizer nitrogen recovery and fertility of yellow-mud paddy soil

【Objectives】Rice straw and milk vetch(Astragalus sinicus L.)plants are important organic nutrient resources in southern China.Thus,the effects of their combined incorporation to field on rice yield,soil fertility,nutrient uptake,and their optimum replacement proportion for chemical fertilizer were studied.【Methods】A field experiment was conducted in a yellow-mud paddy in Fujian for four consecutive years.The experiment involved six different treatments with uniform total N input(135 kg/hm^2)but varying replacement percentage of N from rice straw-milk vetch plants(RM),i.e.0%(RM0,CK),20%(RM20),40%(RM40),60%(RM60),80%(RM80)and 100%(RM100).The rice yield,soil fertility,nutrient uptake,and utilization efficiencies were analyzed.【Results】All treatments with rice straw-milk vetch plants(RM)produced higher rice yield to varying degrees than CK,but the highest increment in the grain(15.4%)and straw(23.6%)yields of rice were found under RM20 treatment,and the yield increments due to RM incorporation declined with replacement percentage higher than 20%.The highest number of effective panicles was also found under RM20 treatment.Compared with CK,all RM treatments increased the uptake of N,P and K by 2.4%–15.4%,2.6%–17.4%,and 2.0%–22.3%,respectively.Similarly,all RM treatments,except RM100,increased the N recovery rates by 2.0–13.5 percent points.The highest increments in the N,P and K,and N recovery rate were found under the RM20 treatment.The RM replacements increased the physiochemical(pH,organic matter,total N,available N,available P,readily available K)and biochemical(microbial biomass carbon,urease and acid phosphatase activity)properties of soil to different extents,but decreased soil bulk density.【Conclusions】The continuous and combined incorporation of rice straw and milk vetch to the field improves soil fertility,nutrient uptake and productivity in yellow-mud paddy soil.More importantly,replacing 20%–40%of chemical fertilizer with combined rice straw and milk vetch plants is recommended for imcreasing rice yield and soil fertility,and reduction in chemical fertilizer application rates.