减氮和配施腐植酸对河西灌区青贮玉米生长、土壤有机碳组分及碳库管理指数的影响OA

[Objective]This study aims to investigate the effects of nitrogen reduction combined with humic acid(HA)application on soil organic carbon components and carbon pool management index of silage corn.[Method]Using the field experiment method,under the same conditions of phosphorus and potassium fertilizer application,six treatments were set up:conventional fertilization(N1),nitrogen reduction of 15%(N2),nitrogen reduction of 30%(N3),conventional fertilization combined with humic acid(N1A),nitrogen reduction of 15%combined with HA(N2A),and nitrogen reduction of 30%combined with HA(N3A).[Result]Compared with conventional fertiliza-tion and nitrogen reduction treatments,the application of HA combined with nitrogen fertilizer increased soil organic carbon and its component content(P<0.05),In the 0～40 cm soil layer,the organic carbon,particulate organic car-bon,soluble organic carbon,and easily oxidizable organic carbon treated with N2A were 1.9%～18.2%,3.3%～27.5%,8.2%～57.5%,and 4.4%～47.9%higher than other treatments,The content of organic carbon(SOC),particulate organic carbon(POC),soluble organic carbon(DOC),and easily oxidizable organic carbon(EOC)in each treatment decreases with increasing soil depth,Compared with conventional fertilization,N1A significantly re-duced mature DOC/SOC,In addition,the sensitivity of SOC and its components to N2A treatment was higher than other treatments in the 0～40 cm soil layer,The combination of nitrogen reduction and HA application increased the carbon pool index and carbon pool management index of the 0～40 cm soil layer to varying degrees,Compared with conventional fertilization,nitrogen reduction and nitrogen reduction combined with HA treatment can improve the dry matter yield of silage corn,and under N2A treatment,it is 10.3%to 28.5%higher than other treatments,There is a significant correlation between the dry matter mass of silage corn and SOC,POC,EOC,DOC and their ratios,as well as the carbon storage management index.[Conclusion]The combination of nitrogen fertilizer reduction and HA appli-cation can significantly increase soil organic carbon and its components,enhance carbon sequestration efficiency,and N2A treatment has the best effect,It can be used as a recommended combination for obtaining the highest biomass of silage corn and improving soil organic carbon pool in Hexi Irrigation Area farmland.