| In order to prevent serious soil erosion, environmental deterioration, and ensure the sustainable use of soil. This paper studys on four land-use modes (wasteland, sisal, sisal×pepper land, agricultural land) of the arid valley in Minjiang River. The reflection of soil fertility on the measurement of soil bulk density, water retention status, porosity, carbon, nitrogen, phosphorus and potassium nutrients in dry or rainy seasons by the means of stratified sampling by section. In order to reveal soil improvement effect of planting sisal and sisal×pepper land and the difference with the agricultural land, to provide an optimal planting pattern for the water conservation and soil fertility restoration in the region, and provide the theoretical basis of vegetation creation and scientific management in the region. The major findings are:1. It presents obvious regulations on two layers of soil bulk density in the dry and rainy season, wasteland is the highest, followed as sisal×pepper and sisal, farmland is the lowest.0-20cm soil, sisal and sisal×pepper soil compare with wasteland on oil bulk density: dry reason reduces 0.20g/cm-3, 0.18g/cm-3; rainy season reduces 0.29g/cm-3, 0.25g/cm-3. 0- 20cm soil, capillary water-holding capacity of sisal and sisal×pepper in the dry reason is respectively 7.36%, 8.23%, higher than the wastelands of 2.26%, 3.13%. The rainy season is 10.39%, 12.43%, higher than the wasteland of 5.29% ,7.33%. The rules on soil capillary pore, non-capillary pore and total porosity rendering: farmland is highest, wasteland is the lowest, wasteland significantly varies in the other three modes, little difference between sisal and sisal×pepper. In addition to the wasteland, capillary pore, non-capillary pore and total porosity of the other three modes in the same soil is the rainy season higher than the dry season.2. PH values are neutral and alkaline in the research soil. Soil organic matter content in the dry- rainy season, farmland is highest, followed as sisal and sisal×pepper, wasteland soil is the lowest. Rainy season compares with the dry season, in addition to wasteland, organic matter of the other three modes has a level of increase in 0-20cm layer of soil. 0-20cm soil layer, four models of total nitrogen in soil in two reasons is farmland > sisal > sisal×pepper> wasteland; wasteland, in addition to wasteland, the other three modes of soil nitrogen content is adequate, but in the dry season, sisal, sisal×pepper soils in easy-to-plant uptake of alkaline hydrolysis nitrogen is not enough. The content of total phosphorus in two soil layers in the dry season: farmland is highest, followed as sisal and sisal×pepper, wasteland soil is the lowest. The content of total phosphorus in two soil layers in the rainy season: farmland > sisal×pepper> sisal > wasteland. Total phosphorus concentration in two periods is lower than 0.1%. Total phosphorus content of four models in the dry season is 7.99 g·kg-1-18.39 g·kg-1. Available phosphorus content in two soil layers in dry-rainy season is farmland > sisal×pepper> sisal > wasteland, available phosphorus content in the wasteland is very low, sisal and sisal×pepper is significant different. Available K content in two soil layers in the dry-rainy season is farmland is highest, wasteland is the lowest. 0-20cm soil layer, Available K content has little difference between sisal and sisal×pepper of two modes in dry season, but of significant differences in the rainy season, in which sisal×pepper is higher than sisal. Available K content in the two-mode types is twice more than the wasteland. Three models of sisal, the sisal×pepper and farmland, in rainy reason compared with dry reason, available K has significant increase in 0-20cm and 20-40cm soil layers, while the available phosphorus only increases little in the 0-20cm.The results show that: soil water and fertilizer efficiency is affected obviously by season changes, particularly the soil available nutrient content changes. In the dry-rainy season, water and fertilizer efficiency in sisal and sisal×pepper is better than wasteland, but worse than agricultural land, water and fertilizer efficiency in sisal×pepper is slightly better than sisal, which is considered as a optimal model in the local.
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