添加富镉稻草对土壤镉含量及活性动态变化的影响机制OA北大核心CSTPCD

To explore the variations in soil cadmium(Cd)activity and its influencing mechanism during the decomposition of rice straw after being returned to the field,this study took soil and rice straw as the research object and carried out soil cultivation experiments using treatments without(T0)and with rice straw(T1)to study the changes in the Cd concentration of rice straw and soil.Dissolved organic matter(DOM)was extracted from the rice straw and DOM treatments at different concentrations(CK,C1,and C2)set up under dark and light conditions,which further revealed the influence and mechanism of rice straw on soil Cd activity.The results showed that,in the soil cultivation experiments,the soil pH first increased and then decreased,Eh first decreased and then increased.And after 90 days of rice straw decomposition,the soil organic matter content increased;the Cd concentration of rice straw decreased by 27.93%;the total Cd concentration of soil increased by 15.79%;and the available Cd concentration of soil first decreased and then slowly increased,but was 9.15%lower than the initial value.The characterization of DOM extracted during the decomposition process of rice straw showed that the DOM of rice straw had high hydrophilicity and molecular weight,and contained functional groups,such as carboxyl and hydroxyl groups.Under light conditions,DOM could increase the soil pH and reduce its available Cd concentration,and the higher the DOM concentration,the more it decreased;the DOM concentrations of C1 and C2 were 0.13 mg·kg-1 and 0.29 mg·kg-1 lower than those of CK,respectively.This study showed that rice straw with Cd could decrease soil Cd activity in a short period of time,and DOM,the main decomposition product of rice straw,could inhibit the migration of Cd in the soil environment under light conditions.