Effects of Different Fertilization Patterns on Soil Available Nitrogen Supply during Soybean Growing Season
This study was conducted to investigate the effect of different fertilization patterns on soil available nitrogen(N)supply during the soybean growing season in fluvo-aquic soil area.Based on a 33-year long-term fertilization experiment,four fertilization treatments were selected:no fertilization(CK),NPK fertilizer(NPK),NPK fertilizer combined with soybean/peanut straw(SNPK),and NPK fertilizer combined with organic fertilizer(MNPK),and the dynamic changes in soil ammonium N(NH4+-N),nitrate N(NO3--N),microbial biomass N(MBN),and dissolved organic N(DON)during the soybean growing season were analyzed.Additionally,organic N mineralizing enzyme activities,soil ammonification intensity,and potential nitrification rate,which involved in soil N transformation,were analyzed.The results showed that the SNPK or MNPK could increase the concentrations of soil total N,organic carbon(C),microbial biomass C,and dissolved organic C.The increases promoted the activities of urease,amidase,protease,N-acetyl-β-D-glucosidase,as well as the ammonification intensity and potential nitrification rate.Soil NH4+-N content was extremely significantly positively correlated with the activities of urease and protease,and significantly positively correlated with amidase activity.Meanwhile,soil NO3--N content showed an extremely significant positive correlation with ammonification intensity and potential nitrification rate.Higher levels of MBN and DON were observed under SNPK and MNPK treatments compared to NPK and CK treatments.There was a significant positive correlation between the dynamics of DON content and soybean shoot N uptake,and which ultimately affected the growth of soybean.At maturity,the aboveground biomass of soybean under SNPK and MNPK treatments was higher compared to CK and NPK treatments.In conclusion,SNPK or MNPK could positively regulate the intensity of soil N transformation microorganisms and enzyme activities by increasing the concentrations of soil total N,organic C and labile organic C.This,in turn,enhanced soil available N supply capacity and promoted the soybean growth.The results of this study provide a theoretical basis for rational fertilization practices in typical fluvo-aquic soil area.
fertilization patternsoil available nitrogenorganic nitrogen mineralizing enzymesammonification intensitypotential nitrification rate
万方数据
维普
