针对黄土高塬沟壑区旱作农田土壤重金属的分布特征及矿质元素含量变化展开研究，旨在评估该区域农田土壤的健康状况及土壤性状发育情况。试验监测区包括黑垆土和黄绵土两种土壤类型，黑垆土属于塬面地形，根据施肥管理分别布设不施肥监测区(CK)、化肥监测区(HF)、化肥有机肥监测区(NPM)和农民地监测区(NM) ；黄绵土属于梯田，该监测区(LS)的施肥管理同化肥监测区(HF)一致。研究结果表明，对于黑垆土，CK监测区Cd元素在剖面表层和中部的含量较底层分布高，Pb、Cr、Ni、As元素随着土层深度的加深而增大；HF监测区Pb、Cr、Ni元素均出现深层累积现象；NPM监测区Cd元素在土壤垂直剖面上出现降低，Pb、Cr、Ni、As元素则出现深层累积；NM监测区Cd、Cr元素底层含量较高，Ni、Hg元素表层含量较高。对于黄绵土监测区，Cd元素在表层和中部含量较其他土层偏高；Pb元素表层含量高；Cr、Ni、Hg、As在土壤垂直剖面上的变化率不大；该类土壤的重金属含量整体低于黑垆土。黑垆土各施肥监测区0 ~ 100 cm土层内Cd、Pb、Cr、Hg元素含量均未超出土壤环境质量一级标准值；CK监测区和HF监测区60 ~ 100 cm土层，NPM监测区10 ~ 20、60 ~ 100 cm土层As元素含量超出土壤环境一级标准值。NM监测区除了Cd元素含量略微高于其他施肥监测区，其余重金属元素含量均相对较低，该研究区域农民地目前的施肥习惯没有造成土壤重金属污染，土壤健康状况较为良好。黄绵土各类重金属在土壤垂直剖面上的分布均小于土壤环境一级标准值，土壤健康状况良好。本研究监测区域土壤矿质元素总体上呈现出SiO₂＞Al₂O₃＞CaO≈Fe₂O₃＞K₂O≈MgO＞Na₂O＞TiO₂＞P₂O₅＞MnO，土壤风化指标表明该区域农田土壤发育较为成熟，耕性良好。

In this paper, in order to assess soil health and soil properties in local farmlands, the profile distribution characteristics of heavy metal and mineral element contents in soil of dry farmlands in the gully area of the Loess Plateau were studied. The monitored area included two kinds of soils: black loessial soil and loessial soil. The black loessial soil locates on the table-land terrain. No fertilizer monitoring area (CK), chemical fertilizer monitoring area (HF), inorganic and organic fertilizer monitoring area (NPM) and farmland monitoring area (NM) were set up according to fertilizer management. The loessial soil locates on the terrace, and the fertilization management was the same as HF. For the black loessial soil, the results showed that the contents of Cd in top layer and middle layers were higher than that of bottom layer; the contents of Pb, Cr, Ni and As were increased with the increase of depth in CK treatment. The concentrations of Pb, Cr and Ni in HF treatment were accumulated in the profile bottom. The content of Cd was decreased with the increase of depth in NPM treatment, and the contents of Pb, Cr, Ni and As were accumulated in the deep layers. For NM treatment, Cd and Cr were higher in the bottom profile, while Ni and Hg were higher in top layer. For loessial soil, the content of Cd was higher in top layer and the middle layers. The contents of Cr, Ni, Hg and As changed little in the profile and the contents of heavy metals in this soil were lower than those in the black loessial soil. The contents of Cd, Pb, Cr and Hg in 0-100 cm soil profile of each fertilization monitored area were not exceed the values of the 1st grade standard of soil environment quality, but the contents of As in 60-100 cm layer in CK monitored area and HF monitored area, 10-20 cm and 60-100 cm layers in NPM monitored area were exceeded the standard value. For NM monitored area, the content of Cd was slightly higher than those of other fertilization monitored areas, and the other heavy metal elements were relatively low. It indicated that the current fertilization in the study area does not cause soil heavy metal pollution and soil health status was well. The profile distributions of heavy metal contents in loessial soil were all smaller than the 1st grade standard of soil environment quality, and soil health was well too. The total mineral content of soil in this study area were in order of SiO₂>Al₂O₃>CaO≈Fe₂O₃>K₂O≈MgO>Na₂O>TiO₂>P₂O₅> MnO. Soil weathering indexes indicated that soils in the study area were developed maturely and had good tillage.

S151.9+3

中国生态系统研究网络(CERN)长武站长期监测项目(K318009703)，退化及未利用土地整治创新团队(2016KCT-23)资助。