不同种植年限温室土壤铅的空间分布特征

Spatial Distribution of Soil Pb in Greenhouse in Different Planting Years

为了探究长期温室蔬菜种植条件下土壤重金属铅的空间分布特征,选取衡水饶阳县蔬菜种植基地,以不同种植年限的温室大棚土壤为研究对象。采用改进的欧共体标准物质局四步连续提取法（BCR）,分析3个土壤层次中全铅、各形态铅、有效态铅含量以及随种植年限出现的积累特性和空间分布特征。结果表明,0~20 cm土壤表层、20~40 cm土壤亚表层全铅含量随种植年限延长表现出积累特性,40~60 cm层全铅含量则表现出随种植年限延长含量降低的趋势;在3层土壤中,表层土壤全铅含量最多,亚表层次之,40~60 cm层全铅含量最少;3个层次各形态铅含量表现为可还原态〉残渣态〉可氧化态〉弱酸态;表层土壤中有效态铅含量最高,危害性较大;表层土壤生物有效性系数随种植年限延长表现出下降的趋势。根据土壤环境质量标准,研究区内土壤Pb含量仍处于一个较低的范围内,但潜在危害较大。

In order to study spatial distribution characteristics of lead in soil in long-term greenhouse,selecting Hengshui,Raoyang County vegetable base,different planting ages of greenhouse soils were studied. Using European Union standards with improved（ BCR） four-step sequential extraction method,weanalyze total lead content,various forms of lead in soil,available lead content and accumulation characteristics in 3 layers of the soil and spatial distribution characteristics with the increase of planting age. Results showed that 0- 20 cm soil surface and20- 40 cm subsurface total lead content exhibited accumulation characteristics with plant life extension. 40- 60 cm layer full lead content showed reduced trend with planting life extended,3 layer soil,the lead conlent in the surface soil was the highest,subsurface followed,that in 40- 60 cm layer least various forms of lead showed. In reducible residua oxidizable weak acid soluble. The effective state lead content in surface soil was supreme,and the hazard was larger. Soil bio effectiveness coefficient in the suifgo decyeastid with planting life extended. Refer to soil environmental quality standard,lead element content in soil in the study area were still in a lower range,but the potential harm seriously.