Effects Of Different Straw Return Patterns On The Physicochemical Properties And Carbon Pool Of Saline Soils

China's agriculture has seen remarkable intensive expansion since the 1950s,and the northeast,as one of the most extensively dispersed regions of black soil,has emerged as a key commercial grain production base in the country.However,the region's ecological ecology has become increasingly unstable as a result of excessive agricultural land reclamation,and land salinization has increased.Many researchers,both domestic and international,have conducted extensive research on saline land improvement in the Northeast,with straw return to the fields being one of the most effective approaches.At the same time,as China's population grows,so does its demand for food,and it is critical to expedite the development of saline lands in this setting..Straw return to the field,as one of the most important agricultural conservation techniques,is not only beneficial in enhancing total nutrient and quick-acting nutrient content over time,but also has a significant impact on soil fertility.However,there is a scientific gap in our knowledge of straw return to the field.As a result,this paper uses this as a starting point and chooses the Dorbert Mongolian Autonomous County of Daqing City as the research area,using a combination of indoor and field experiments to investigate the environmental effects of different straw return modes(crushing,adding decomposition agent,adding biochar,ammonification,etc.)and physicochemical analysis techniques to investigate the environmental effects of different saline land treatments.The conclusions are as follows:1.The addition of straw,decomposition agent,biochar and organic fertilizer in the indoor treatment all affected the soil nitrogen content.When the water content was 50%pore filling degree,the soil TN,NH₄⁺-N and NO₃^--N contents of each treatment group showed a decrease compared with CK;when the water content was 80%pore filling degree,the nitrogen content of each treatment group increased to different degrees compared with CK;the crushed The crushed straw with nitrogen fertilizer treatment was the most obvious.Soil cation exchange was improved to different degrees and pH values were reduced.2.The addition of wild crushed straw,decomposition agent,nitrogen fertilizer,ammoniated straw and biochar caused an increase in soil nitrogen content,soil electrical conductivity and soil water content,a decrease in cation exchange,pH and an improvement in soil soluble salt content during the non-growing season;and a decrease in nitrogen content,cation exchange,pH,electrical conductivity and soil soluble salt content and an increase in soil water content during the growing season.3.The different treatment modes increased the field soil organic carbon content and dynamic organic carbon content,decreased the soil dissolved organic carbon content in the short term,and the material addition improved the soil carbon pool management index,and improved the stability of soil organic carbon in the short term.4.Indoor treatments with straw,decomposition agent and nitrogen fertilizer were the most effective in improving soil quality,and treatments with straw,decomposition and nitrogen fertilizer during the non-growing season in the field significantly improved soil quality,and treatments with ammoniated straw during the growing season were the most effective.On the whole,crushed straw with nitrogen fertilizer and decomposition agent,or ammonification of straw is more suitable for soil improvement of saline land in the western part of the Songnen Plain.