经济发达区土地利用变化对土壤性质的影响——以江苏省昆山市为例

在高速工业化和城市化的江苏省昆山市选择6种典型农用土地利用方式,78个土壤样点剖面,对不同土地利用类型的土壤性质进行对比分析。结果显示,土地利用变化对土壤养分、土壤重金属污染有明显的影响,除速效钾外,2002年的土壤养分含量比1981年有所提高。同时发现2002年有机质含量在不同用地类型之间存在明显的规律,即水稻田>园地>抛荒地>菜地;全氮、速效氮含量规律为水稻田>园地>菜地>抛荒地;速效钾的含量规律是园地>水稻田>抛荒地>菜地;速效磷的含量规律是抛荒地>菜地>园地>水稻田。2002年土壤pH值、有机质和全氮含量的变异系数明显高于其他土壤养分,其中全氮含量的变异系数最大。不同土地利用类型中的不同重金属含量表现强弱不一,水稻田土壤的Hg、Cr、Ni、Cd的含量明显高于其区域土壤背景值,而菜地含量比较高的重金属是Hg、Ni、Cu;园地和抛荒地各重金属含量相对较低,但其Ni含量与水稻田和菜地相当。此外,土地经济系数与土壤养分及土壤污染指数具有强相关性。

Effect of Land Use Changes on Soil Conditions in the Developed Areas: A Case of Kunshan in Jiangsu Province

In order to study soil property change in the rapid urbanization and industrialization process,6 typical land use patterns were chosen to study the effect of different land use patterns on soil nutrient,soil pollution and so on in Kunshan,Jiangsu province.We drew conclusions as follows:Firstly,it is clear of the effect of land use change on soil nutrient,soil pollution.Besides the available-K,land use change results in the increase of soil nutrient from 1981 to 2002.And the change extent of organic matter,total-N and available-N contents is different in different typical land use patterns,the order of organic matter contents in 2002 is paddy field>garden land>uncultivated land>vegetable land,the order of total-N and available-N contents is paddy field>garden land>vegetable land>uncultivated land,the order of available-K content is garden land>paddy field>uncultivated land> vegetable land,and the order of available-P content is uncultivated land>vegetable land>garden land>paddy field.Secondly,the variation coefficients of organic matter and total-N content are apparently higher than other soil nutrients,and the variation coefficient of total-N content is the highest.Thirdly,land use change impacts heavy metal concentration,the Hg,Cr,Ni and Cd contents in paddy field are higher than the background level,and the Hg,Ni and Cu contents are higher in vegetable land,heavy metal concentration is lower in garden land and uncultivated land,but Ni content in garden land and uncultivated land is at the same level with other typical land.Finally,the land economic coefficient correlates highly with soil nutrient and soil pollution.