三峡库区小流域土地利用方式对土壤肥力的影响

Effects of land use types on soil fertility in small watershed in the Three Gorges Reservoir

为探讨三峡库区小流域不同土地利用方式对土壤肥力的影响特征,采用野外调查、取样和室内实验分析相结合的方法,对三峡库区五桥河流域内3种主要土地利用方式(旱地、柑橘园、林地)的土壤理化性状进行对比分析。结果表明,不同土地利用方式对土壤肥力具有较为明显的影响,土壤孔度、渗透率变化由大到小的次序为林地→柑橘园→旱地;土壤有机质和氮、磷、钾养分含量由大到小次序为林地→柑橘园→旱地。这与不同土地利用方式下人类耕作活动、对土地的劳力与经济投入不同密切相关。林地受人为扰动少,因而土壤肥力高;柑橘园、旱地受人类耕作活动影响大,但因柑橘园经济产出效益较高,农户对土地的投入相应较高,使得柑橘园土壤肥力高于旱地土壤。

Land utilization plays an important role in both environment and sustainable agricultural development in the Three Gorges Reservoir. Preventing soil erosion and improving soil fertility is the main target of the rational and effective land use. By the method of soil sampling and laboratory analysis, effects of different land use types on soil fertility have been discussed in this paper. Three main types of land use including farmland, orchard land and forest land in Wuqiao watershed, Chongqing, China, have been selected, and soil physical and chemical properties have been studied. The results show that the different land use types have significant impacts on soil fertility. Soil porosity, permeability coefficient and nutrient content including organic matter, total N, total P, total K, hydrolysable N, available P and available K decline in sequence from forest land, orchard land to farmland.