Effects of Land Use and Management on Soil Fertility in the Middle Karst Region of Guizhou Province

The changes of soil physical,chemical and biological properties under different land use and management sgstems were investgated in the middle karst region of Guizhou provinve.The results showed that the land use systems marked differences in soil fertility indicators,including soil particle composition,porosity distribution,bulk density,water-holding capacity,organic matter and nutrient contents and soil microbes.Most of these soil fertility indicators were the highest in the forest intercropped with crops and perennial grass(agroforestry systems),intermediate in the well-management irrigated farmland,and the lowest in the sloping cropland.It was suggested that a long-term input of organic matter was needed for the reestablishment of soil carbon and nitrogen pools in the seriously degradaed ecosystem.Inappropriate land use and management could rapidly worsen soil fertility.Hence,from a perspective of soil resource conservation,a preferable way for preventing soil degradation and achieving sustainable land use should be to give up the cultivation of degraded farmlands,and to adopt more effective and appropriate soil management and cultivation practices.