绿肥还田结合减氮对麦田土壤呼吸及其温度敏感性的影响OACSTPCD

This study was conducted to explore the effects of green manure incorporation combined with nitrogen fertilizer reduction on the soil respiration dynamics of wheat fields and wheat yield in oasis irrigation areas.This study was performed to provide a theor-etical basis for the study of carbon emission reduction in farmlands in arid oasis irrigation areas.The experiment was conducted in 2021 and 2022 in the Hexi Oasis irrigation area.With the conventional nitrogen application without green manure(N100)as the con-trol,we performed the following treatments:15 000 kg·hm-2 green manure+85％nitrogen fertilizer(G1N85),22 500 kg·hm-2 green manure+85％nitrogen fertilizer(G2N85),30 000 kg·hm-2 green manure+85％nitrogen fertilizer(G3N85),15 000 kg·hm-2 green ma-nure+70％nitrogen fertilizer(G1N70),22 500 kg·hm-2 green manure+70％nitrogen fertilizer(G2N70),and 30 000 kg·hm-2 green ma-nure+70％nitrogen fertilizer(G3N70).There were seven treatments in total.Soil respiration rate,carbon emissions,yield,and carbon emission efficiency during the wheat growth period were explored,and the response of soil respiration to soil temperature was ana-lyzed.The results showed that the soil respiration rate under different treatments showed a single-peak trend of initially increasing and then decreasing,and the variation range was 0.8 to 6.2 μmol·m-2·s-1 during the whole growth period.The combination of green manure incorporation and nitrogen fertilizer reduction significantly increased the soil respiration rate and the total soil carbon emis-sions of wheat fields.When compared with N100,the average increases were 7.2％-19.8％and 5.7％-18.8％,respectively.G3N85 and G3N70 increased the soil respiration rate by 2.3％-16.0％and 3.3％-19.8％,the total soil carbon emissions by 2.9％-15.2％and 3.1％-18.8％,respectively(P＜0.05),when compared with the other treatments.Compared to G3N85,the average soil respiration rate and total soil carbon emissions of G3N70 treatment increased by 3.3％and 3.1％,respectively(P＜0.05).Green manure incorporation combined with nitrogen fertilizer reduction significantly decreased the temperature sensitivity of soil respiration(Q10),and when com-pared with N100,the Q10 values decreased by 10.4％-18.1％(P＜0.05).Green manure incorporation combined with nitrogen fertilizer reduction could significantly affect wheat yield and soil carbon emission efficiency,with the G3N85 treatment significantly higher than the other treatments by 4.2％-45.6％and 0.3％-26.4％(P＜0.05).In conclusion,green manure incorporation combined with nitrogen fertilizer reduction enhanced the soil respiration of wheat fields while reducing the temperature sensitivity of soil respiration.It also improved wheat yields and carbon emission efficiency.Green manure incorporation at 30 000 kg·hm-2 combined with nitrogen fertil-izer reduction by 15％(G3N85)proved to be an effective way for nitrogen reduction and emission mitigation while improving soil pro-ductivity for wheat fields in Hexi Oasis irrigation area.