生物降解地膜覆盖对滨海盐碱耕地土壤环境、碳固存和大豆产量的影响OA

To explore the effects of different biode-gradable plastic film mulching practices on soil environ-ment,carbon sequestration,and soybean yield in coastal saline-alkali land,this study set up five treatments:no film mulching(control,CK),polyethylene film mulching(PE),biodegradable plastic film mulching with a functional lifespan of 55-65 days(BDM1),biodegradable plastic film mulching with a functional lifespan of 65-75 days(BDM2),and biodegradable plastic film mulching with a functional lifespan of 75-85 days(BDM3).The results showed that biodegradable plastic film mulching affected soil nutrient contents mainly by regulating soil temperature and moisture.The soil salt content and pH under biodegradable plastic film mulching treatments were lower than those of the control,while the average soil temperature and average soil moisture were higher than those of the control.The soil organic carbon content and organic carbon storage in the BDM2 treatment were significantly higher than those in the CK,PE,BDM1,and BDM3 treatments(P＜0.05).The contents of water-stable aggregates,mean weight diameter,and geometric mean diameter of soil in the BDM2 treatment were significantly higher than those in the CK,PE,BDM1,and BDM3 treatments(P＜0.05).In addition,the fractal dimension of soil aggregates in the BDM2 treatment was significantly lower than that in the CK,BDM1,and BDM3(P＜0.05).The contents of aggregate-associated organic carbon and microaggregate-associ-ated organic carbon in soil under the PE,BDM1,BDM2,and BDM3 treatments were significantly higher than those in the CK(P＜0.05).The contents of macroaggregate-associated organic carbon,mesoaggregate-associated organic carbon,and microaggregate-associated organic carbon in the BDM2 treatment were significantly higher than those in the CK,PE,and BDM1 treatments(P＜0.05).In conclusion,biodegradable plastic film mulching inhibited soil salt return by improving soil hydrothermal conditions,promoted aggregate stability and organic carbon accumulation,improved soil structure,en-hanced soil nutrient availability,and then increased soybean yield.Among these treatments,the BDM2 treatment exhibi-ted the most significant effects on soil improvement and yield increase,which could replace traditional polyethylene film and be popularized and applied in coastal saline-alkali farmland of Jiangsu province.