秸秆还田配施硫酸对苏打盐碱土壤改良效果研究OA

[Objectives]Saline-sodic land is a reserve land resource with great utilization potential in our country.Straw returning to the field can improve the physical and chemical properties of soil,increase the supply of soil nutrients,promote crop growth,and thus achieve the purpose of increasing production.Sulfuric acid applied to sodic saline-alkali soil can reduce soil pH value,activate soil inherent calcium,and provide calcium source for replacing exchangeable sodium in soil,but the improvement effect of different amounts of straw returning and sulfuric acid on saline-alkali soil is not clear.The paper aimed to further explore the effect of straw and sulfuric acid combined application in the improvement process of saline-sodic soil.[Methods]A pot experiment was conducted,which included 4 straw returning rates and 6 sulfuric acid application rates.The amounts of straw returned to the field were 0,3,6 and 9 t·hm-2,respectively,and the application rates of sulfuric acid were 0,1.5,3.0,4.5,6.0 and 7.5 t·hm-2,respectively.A total of 24 treatments were set up by combining the application of straw and sulfuric acid.The effects of different application rates of straw and sulfuric acid on soil chemical properties and rice yield were determined,and the soil improvement effect was evaluated using the fuzzy matter-element entropy weight model.[Results]Under different straw returning amounts,applying different dosages of sulfuric acid could significantly reduce the pH value,sodium adsorption ratio and total alkalinity of soda saline-alkali soil.Within a certain range,the contents of Na+,Ca2+,Mg2+,K+and SO42- in the soil all increased with the increase of sulfuric acid dosage.Straw returning combined with the application of an appropriate dosage of sulfuric acid could effectively enhance soil organic matter and increase rice yield.Based on the fuzzy matter-entropy weight model,it could be concluded that the effect of half-amount straw returning with sulfuric acid on saline-alkali properties of saline-sodic soil and rice yield and yield components was better.The optimal application amount of sulfuric acid was 4.5 t·hm-2.The optimal amount of sulfuric acid applied alone without straw was 3 t·hm-2,and the optimal amount of sulfuric acid combined with full and 1.5 times straw returning was about 1.5 t·hm-2.[Conclusions]Through this study,we could reveal the mechanism of action of the two synergies on soil chemical properties,and determine the optimal amount in the field,so as to provide the best scheme for the collaborative acidification of saline-sodic rice straw returning to the field,and provide a reasonable theoretical basis for improving salinized soil and increasing rice yield.