Abstract:

There is serious contradiction between human and land in Three Gorges Reservoir area for a long time.Water storage and resettlement make land resources further reduce.At the same time,the decrease of soil fertility and ecological degradation caused by excessive development has become more and more serious.Soil fertility and variation tendency of different land use and different altitudes in Shuitianba Village of Zigui County in Three Gorges Reservoir area were analyzed,with soil sampling and investigation.The results show that terraced fields and protective cultivation were commonly used in the study area.The area of altitude 600~700 m was mainly opened for oranges orchard,the area altitude 700~900 m was mainly grow conventional crops.The soils in the study area were featured by thick ossification and desertification,and its fertility characteristics are weak waterretaining property,poor waterstable aggregate,good ventilation and water permeability,and easy farming.Content of soil organic matter (SOM) in the study area was generally low,but content of SOM and total nitrogen (TN) in middle and high elevation area was relative high,and content of soil total phosphorus (TP) and total potassium (TK) in low elevation area was relative high.Slope land changing to terraced fields helped to improving soil fertility and increasing soil nitrogen and phosphorus.According to the continuous monitoring result of 2005~2010 years,soil fertility was generally low in the study area,which became constraints for local agricultural production,and soil fertility degradation trend is still not controlled in mountain area at present. Because of soil and water loss and excessive use of chemical fertilizer,the content of SOM,TN,TP,and TK in most of the soil in the study area decreased,but content of soil available nutrient increased