摘 要 ：利用渗漏池设施，研究了冬小麦-夏玉米轮作条件下不同土壤深度对土磷素淋失的影响。种植8季作物结果表明，对深度小于80 cm 的渗漏池，淋出土体的累积渗滤液量和累积全磷量随化学磷肥施用量的增加而减少; 随土层深度的增加，淋出土体的渗滤液和磷量均减少，且二者的减少率都很接近，表明磷素淋失主要受通过土体的土壤水分控制。相对于深度小于80 cm的土层，供试土壤的粘化层有效地减少了土壤渗滤液和磷素淋失。各深度渗漏池渗滤液中的磷以可溶态为主，约占全磷的70%左右，颗粒磷约占30%。合理施肥并加强水分管理是土区减少磷素向土壤深层迁移的有效手段。
Abstract:Effects of soil depths on phosphorus leaching losses under the rotation system of winter wheat summer maize in manural loess soil were studied by using lysimeters with refilled soil. The results showed that the cumulative leachates and total phosphorus (TP) losses were decreased with the increase of phosphate fertilizer rates in the lysimeters when soil depth is less than 80 cm. The cumulative amounts of leachates and TP in the leachates were reduced with the increase of soil depth under the various fertilizer treatments. The decreased ratios of cumulative leachates were similar to those of total phosphorus in the leachates from the lysimeters those have a soil depth of 80 cm compared with 50 cm soil depth in all treatments. The argillic layer at the depth of from 77 to 155 cm in the soil significantly impedes the downward movement of soil water, thus the leaching losses of phosphorus. Phosphorus leaching was observed mainly in the form of dissolved phosphorus, and the proportion of total dissolved phosphorus to total phosphorus in the leachate was about 70%, while particulate phosphorus accounted for about 30% of the total leached P. The effective management of soil water and fertilizer P would be the most efficient approach to mitigate the downward movement of soil phosphorus in loessial region.