黄土高原残塬沟壑区梯田土壤重金属分布特征

本文对黄土高原残塬沟壑区梯田土壤中的重金属分布特征进行了探讨，发现除铜处于污染临界值外，其它重金属如汞、砷、铬、镍、锌的土壤含量基本达到一级标准。随种植时间的增长土壤中重金属的含量也随着积累，在坡耕地中除汞和锌外，其它重金属在土壤中的含量随着坡度的增大而减少。在表层土壤中重金属汞、铜、锌、镍和砷的含量由大到小的次序为：果园＞麦田＞坡地，而铬在表层土壤中的含量大小次序为：麦田＞坡地＞果园。研究表明重金属在水平梯田中易累积，同时由于梯田果园长期大量使用农药、化肥，更容易累积有害元素，从而形成对土壤的污染，进而影响土壤质量。以后应加强对土壤质量的监测与防治，实现黄土高原地区果业、粮业的健康稳定发展。

Heavy Metal Distribution Feature in Terrace Soil on the Loess Gullied-Hilly Area

In southern Loess Plateau, approached the distributed status of heavy metals in terrace field in gullied-hilly area, discovered the soil contents of Cu come within critical value, and the soil content of other heavy metals such as Hg, As, Cr, Ni and Zn could reach the first soil quality standard. In the area, it was found that heavy metals＇ content in soil did not fit general regularity. With the growth of planting time, the contents of heavy metals accumulated and reduced with increasing of gradient. The contents of Hg, Cu, Zn, Ni and As in top soil of orchard terrace were bigger than those of cornfield and sloping field, but the content of Cr of cornfield was bigger than that of sloping field and orchard terrace. The results showed the heavy metal was easily accumulated in level terrace, especially in the orchard terrace. Monitoring and cure of soil quality should be studied to instruct apple and grain industry development continually on the Loess Plateau.