Soil Chemical Properties Under Various Land-Use Types In The Karst Area With A Case Study In Shibing County Of China

The effects of different land-use types on the pH, organic carbon, total nutrient, and available nutrients of soil in the 0-30 cm and 30-60 cm layers were studied using the gray relational analysis method. The research area is located in Baiduo village in the dolomite karst region and Shiqiao village in the limestone karst region of Shibing County, Guizhou Province, China. The land-use types investigated included shrubland, forest, grass slope, dryland, paddy field, pear orchard, and flue-cured tobacco field. The contents of organic carbon, total nitrogen, alkaline hydrolysable nitrogen, and available potassium, as well as the pH of the soil in the dolomite shrubland, were higher than those in the limestone shrubland. The total potassium, total phosphorus, and available phosphorus contents of soil in the limestone shrubland were higher than those in the dolomite shrubland. Among the four types of land-use most strongly affected by human activities (paddy field, dryland, flue-cured tobacco field, and pear orchard), the nutrient contents (except potassium in the upper soil layer) were higher than those in the lower layer. The differences in nutrient contents between upper and lower layers were relatively small in the dryland and the pear orchard, whereas they were large for the paddy field and flue-cured tobacco field. The gray relational degree of various land-use types decreased in the following order: dolomite shrubland > forest > grass slope > pear orchard > limestone shrubland > paddy field > dryland > flue-cured tobacco field. The dolomite shrubland had the best soil quality, while the flue-cured tobacco field had the worst. Of the four types of land use most strongly affected by human activities, pear orchard had the best soil quality. This study can provide reference for soil nutrient management and sustainable management in karst areas.