高产田养分平衡及其环境风险特征研究

选择连续四年产量20000kg·hm-2以上的高产田为研究对象,并以当地常规农田为对照,分析了秸秆还田条件下冬小麦-夏玉米高产轮作体系中养分平衡及环境风险特征。结果表明,高产田和常规农田的氮、磷、钾素在冬小麦-夏玉米轮作体系中都有盈余,分别盈余130和202、122和162、315和119kg·hm-2。高产田氮素和磷素的盈余量小于常规农田,钾素盈余量高于常规农田。在冬小麦-夏玉米轮作体系的各生育期,高产田0～100cm土体硝态氮均存在大量累积,小麦季大于玉米季,高产田大于常规农田,存在较高的淋溶风险。土壤电导率均小于土壤盐渍化的临界值,尚未出现土壤盐渍化的现象。

Nutrients balance and environment risk in high yield field

The characteristics of nutrient balance of N, P, K and their environment risk under straw returning were investigated in the rotation of winter wheat and summer maize in High-yield field （HF： with the yield 20 000 kg·hm-2 a-1） and Conventional field （CF）. The results showed that total input of N, P and K in winter wheat and summer maize rotation system were higher than those of output, with the surplus of 130 and 202, 122 and 162, 315 and 119 kg·hm-2 in High-yield field and Conventional field, respectively. The surplus levels of N and P in HF is lower than those in CF, however, K surplus showed the reverse trend. High level NO3--N accumu-lated in soil profile of 0-100 cm during one rotation in HF. NO3--N accumulation is more during growth period of winter wheat than that of summer maize and higher in soil of HF than that in CF, which had a potential risk to NO3--N leaching from soil to groundwater. Soil conductivity is lower than the critical value of soil salinization.