城郊不同土地利用方式坡地土壤养分空间动态研究

随着城市化的发展,城郊土地利用方式的转型异常明显。为了研究土地利用转型及人为活动对坡地土壤养分空间动态的影响,以杭州市西郊的低山丘陵区为研究区,选择混交林、竹林、和坡耕地3种土地利用类型的坡地,进行了坡地三维空间采样和室内N,P,K含量的测定。在系统分析的基础上,得以下结论:(1)坡耕地土壤N,P,K的绝对含量最高,空间变化以5 cm土层波动最大;竹林地则以10 cm土层波动明显,混交林地空间分布规律性高;(2)3种土地利用方式坡地中N,P,K养分从坡顶到坡底总的趋势是呈递减状态,其中坡耕地递减强度最大;(3)3种土地利用类型中,N,P,K含量空间动态差异的主要原因是土地利用方式不同,人为活动方式、强度、频率和深度不同所致;(4)坡地土壤养分流失的总趋势与坡面汇流和土壤侵蚀规律相一致。

Spatial Distribution of Soil Nutrient on Sloping Land With Changed Land Utilization Ways in Suburbs

In the urbanization process,the change in land utilization is very swift.In order to investigate the effects of land utilization change and human activity on the spatial distribution of soil nutrient,we took the western suburb of Hangzhou as a research area.Sloping lands with three utilization ways of mixed forest,bamboo forest and cultivated sloping land were selected.In the horizontal direction,the whole sloping land was divided into four slope segments of the top,upper,lower and bottom,each of which has three samplings taken.In vertical direction,three depths at each sampling point were determined,i.e.,5,10 and 15 cm.Totally,36 samples were taken.The contents of N,P and K for each sample were measured,and 108 data were obtained for analysis.According to the measurements and systematic analysis,some conclusions have been gained.The absolute contents of N,P and K are the highest and the change in spatial distribution is the most obvious at the depth of 5 cm on sloping land.However,the most obvious change is observed at the depth of 10 cm on sloping land with bamboo forest.The change in the spatial distribution of the contents of N,P and K is very distinct.From the top of sloping lands to the bottom,the contents of N,P and K show a decreasing trend,and the intensity of decreasing trend is the greatest on sloping land.The main reasons for soil nutrient changes are the different ways of land utilization and the intensity and frequency of human activities.Loss of soil nutrient on sloping land is coincident with soil and water loss and water confluence.