不同氮磷钾配比施肥对无患子土壤-微生物碳氮磷化学计量特征的影响OA

[Objective]This study aims to investigate the soil organic carbon(SOC),total nitrogen(TN),total phosphorus(TP),microbial biomass carbon(MBC),microbial biomass nitrogen(MBN)and microbial biomass phosphorus(MBP)contents and their stoichiometric relationships under different NPK fertilizer ratios in the Sapindus mukorossi plantation soil,and provide theoretical bases for the nutrient management of the plantation and the scientific cultivation of woody oilseed species.[Method]Using S.mukorossi'Yuanhua'as the research material,the"3414"fertilization test group design was adopted,and different ratios of nitrogen(N),phosphorus(P)and potassium(K)fertilization tests were carried out[0 level(CK):no fertilization of N,P and K;one level:N fertilizer 300 kg/hm2,P fertilizer 250 kg/hm2,and K fertilizer 200 kg/hm2;Two level:N fertilizer 600 kg/hm2,P fertilizer 500 kg/hm2,K fertilizer 400 kg/hm2;Three level:N fertilizer 900 kg/hm2,P fertilizer 750 kg/hm2,K fertilizer 600 kg/hm2].SOC,TN,TP,and MBC,MBN,MBP content in forest soils were measured.The soil-microbial stoichiometric ratios for carbon,nitrogen,and phosphorus were calculated.This study analyzed the effects of different fertilization treatments on the content and stoichiometric ratios of SOC,TN,TP,MBC,MBN and MBP in forest soils of S.mukorossi'Yuanhua'.Combined with correlation analysis,redundancy analysis,and membership function analysis.[Result]Compared with CK treatment,fertilization with different nitrogen,phosphorus and potassium ratios had a significant effect on SOC,TN,TP and MBC,MBN and MBP contents of S.mukorossi soils,which increased by 14.25％-52.61％,3.90％-39.84％,9.52％-150％,6.65％-47.45％,11.84％-46.50％and 14.91％-201.98％compared with CK,respectively.Regression analysis showed that the internal stability indices of MBC,MBP and their MBC/MBP and MBN/MBP were all in 0.50-0.75,which were weakly sensitive characteristics.The internal stability index of MBN was 0.29,indicating weak homeostasis,while that of C/N was≤0,reflecting strong homeostasis.Redundancy analysis showed that SOC and TP contents were the main factors affecting soil MBC,MBN,MBP contents and stoichiometry.Correlation analysis showed that SOC was highly significantly positively correlated with TN,TP,C/N,MBC,and MBN,and significantly negatively correlated with N/P.Soil TP and MBP were highly significantly correlated with MBC and highly significantly negatively correlated with C/P,N/P,MBC/MBP and MBN/MBP.According to the comprehensive evaluation and analysis of the affiliation function method,the fertilizer treatment with the ration combination N1 P1 K2(N fertilizer 300 kg/hm2,P fertilizer 250 kg/hm2,and K fertilizer 400 kg/hm2)can improve the soil nutrient content of S.mukorossi in different degrees.[Conclusion]From the comprehensive analysis,different NPK ratios of fertilizer application obviously changed the MBC,MBN and MBP contents of forest soil and their stoichiometric ratio characteristics,and the N1 P1 K2 treatment could obviously improve the conversion and decomposition of microorganisms on soil carbon,resulting in changes in the stoichiometric ratios of organic matter and microbial biomass,and then improve the ability of S.mukorossi in fixing soil carbon.