Characteristics of Soil Nutrient under Different Land Use Types in Karst Mountain Area

The land use types affect the nutrient feature and the texture of soil.It studies the soil nutrients under 6 different land use types including shrub-grassland,plantation,orchard,dry land,paddy fields and abandoned land in Nanchuan District of Chongqing.The outcomes show that the soil nutrient contents are difference under different land use types and the variation laws are also different.The contents of organic matter,total nitrogen,available nitrogen,available phosphorous and available potassium of soil under the 6 different land use types all show accumulation in surface soil,and the contents of organic matter,total nitrogen and available nitrogen decrease progressively along with the increase of the depth,but the contents of total phosphorous and total potassium do not show significant variation law.The sequences of indexes of soil nutrient content under 6 different land use types are different and part of soil nutrient contents are still low after returning farmland.It initially considers that the soil nutrient contents are seriously affected by human and the capability of soil restoration after returning farmland is lower.