水分调控下旱地土壤中毒死蜱的消解研究

为探讨水分调控下旱地土壤中毒死蜱的消解特性，通过盆栽试验及通径分析方法，研究了不同水分条件下旱地土壤中毒死蜱消解速率及其与土壤性质之间的关系.结果表明:①土壤中毒死蜱的消解速率随时间的延长而逐渐减缓，并且不同水分条件下土壤中毒死蜱的消解速率不同，施药45 d后，5个水分处理（20% FC、40% FC、60% FC、80% FC和100% FC，表示田间持水量依次为20%、40%、60%、80%和100%）下毒死蜱的消解率分别为65.58%~85.56%、70.71%~89.64%、76.30%~95.33%、72.53%~97.60%和70.57%~90.80%，其中以80% FC下的消解速率最快，60% FC下次之.②一级动力学方程能较好地描述土壤中毒死蜱的消解过程（R2>0.88），消解速率常数（k）最大为0.099 0 d-1.③土壤中毒死蜱的消解速率与w（有机碳）、w（DOC）（DOC为可溶性有机碳）和w（MBC）（MBC为微生物量碳）均呈显著相关.通径分析结果显示，水分条件的改变致使土壤中w（有机碳）、w（DOC）和w（MBC）发生变化，进而对土壤中毒死蜱的消解速率产生较大影响.④大豆、玉米和小麦根际土壤中毒死蜱消解速率均快于非根际土壤，根际土壤中毒死蜱消解速率表现为大豆土壤（0.099 0 d-1）>玉米土壤（0.080 6 d-1）>小麦土壤（0.069 6 d-1）.研究显示，改变土壤水分含量可有效调节土壤中毒死蜱的消解，并为农业生产中毒死蜱的安全施用提供参考依据. 

Dissipation of Chlorpyrifos in Dryland Soils under Moisture Content Variations

In order to study the effect of soil moisture content on the dissipation of chlorpyrifos in dryland soils, the dissipation of chlorpyrifos in soil under different moisture conditions was investigated, and the relationships between dissipation rate of chlorpyrifos and the soil properties in dryland with different moisture content were analyzed by pot experiments and path analysis. The results show that:(1) The dissipation rate of chlorpyrifos gradually decreased with time. Meanwhile, there was a significant difference in the dissipation rate of chlorpyrifos under different moisture treatments. After 45 days, the dissipation rates of chlorpyrifos under different moisture treatments (20% FC, 40% FC, 60% FC, 80% FC and 100% FC, which in turn represent 20% , 40% , 60% , 80% and 100% of the field capacity) were 65.58% -85.56% , 70.71% -89.64% , 76.30% -95.33% , 72.53% -97.60% and 70.57% -90.80% , respectively. The chlorpyrifos in soils was dissipated most rapidly under 80% FC conditions, followed by 60% FC. (2) The dissipation process of chlorpyrifos in soils were well fitted by the first-order kinetic model (R²>0.88), and the maximum value of k was 0.0990 d^-1. (3) The dissipation rate of chlorpyrifos in soils was significantly correlated with soil organic carbon, dissolved organic carbon, and microbial biomass carbon. The path analysis shows that the contents of organic carbon, dissolved organic carbon, and microbial biomass carbon in soils changed under different moisture conditions, which further affected the dissipation rate of chlorpyrifos. (4) The results also show that the dissipation rate of chlorpyrifos in soybean, corn, and wheat rhizosphere soil was faster than that in non-rhizosphere soil. The dissipation rate of chlorpyrifos in rhizosphere soil followed the order of soybean soil (0.0990 d^-1) > corn soil (0.0806 d^-1) > wheat soil (0.0696 d^-1). The dissipation of chlorpyrifos in soils was effectively regulated by the change of moisture content, which is expected to provide important information for safe application of chlorpyrifos in agricultural production.