Influence of nitrogen fertilizer reduction on soil microbial biomass in Korla scented pear orchards
[Objective]Exploring the changes of soil microbial biomass carbon(ωc)and soil microbial mass nitrogen(ωN)in Korla pear orchard under different nitrogen fertilizer dosage,clarifies the influence of different nitrogen fertilizer application on soil microbial quantity in Korla pear orchard,and proposed the most suitable nitrogen fertilizer application,which can provide a theoretical basis for the reasonable fertilization in Korla pear orchard.[Method]Taking the soil of 10-12 a Korla pear orchard as the material,field erperiment were conducted to set up no fertilizer treatment(N0P0K0),no nitrogen fertilizer treatment(N0PK),conventional fertilizer treatment(NPK),and three nitrogen fertilizer reduction gradients treatments(N1PK,N2PK,N3PK,respectively,10%,20%,30%less nitrogen than the conventional fertilizer),which were recorded as CK,N0,N,N1,N2,and N3,respectively.Fumigation extraction-volumetric analysis and ninhydrin colorimetric method were used to determine soil microbial mass carbon and soil microbial mass nitrogen,and to analyze the correlation between soil microbial mass and yield.[Result]Within the 0-60 cm soil layer,soil microbial mass carbon and nitrogen showed a decreasing trend with the increase of soil depth.Throughout the reproductive period,N2 and N3 treatments were more effective in reducing ωc and ωN contents than N treatment.In the 20-40 cm soil layer at the fruit-setting stage,the ratio of ωc to ωN values increased significantly with the N2 treatment compared with the N treatment.In the 20-40 cm soil layer during fruit-setting and fruit-swelling period and in the 40-60 cm soil layer during maturity stage,the N3 treatment promoted soicl microbial carbon entropy(qC)significantly more than the N treatment,but significantly reduced the yield of Korla scented pear;yield and ratio of ωc to ωN,ωc′(organic carbon)was significantly positively correlated with ωc,ωN,qN,ωN′(total nitrogen)was highly significant positively correlated with ωc,ωN,qN,ωN′.[Conclusion]In this study,according to the comprehensive effect of nitrogen reduction fertilization on soil microbial mass and yield,the recommended 10-12 years old Korla scented pear nitrogen fertilizer suitable application range of 240-270 kg/hm2,that is,complete application of nitrogen(300 kg/hm2)based on nitrogen reduction of 10%-20%.
NETL
NSTL
万方数据
