Soil Effect On Vegetation Restoration And RE Construction In Loess Gully And Hilly Region

Taken for Shaanxi Province, Wu Qi County, an example, according to soil genesis, restoration ecology, and subject theo9ry related, from different ecological zones of various types of vegetation restoration of a typical soil-plant system against serious degradation of the ecosystem restoration of vegetation on soil environmental impact and role of the systems. Through field investigation, field observations, laboratory analysis and test tools, explore measures to restore soil fertility and the mechanism of the formation, evolution model, Soil formation and development process of succession to effectively improve the quality of soil fertility vegetation cover types, rational use of land resources to provide basis for decision-making.(1) In Riverland, 0-20 cm surface soil, TN, AN, AP, AK and CEC content were the highest in the fourth farmlands. According to the Loess Plateau surface soil grading standards, AP and AK was the third level, they were more abundant; Stream soil nutrient content was after the riverland, the nutrient of sloping land and Ping soil was poor quality. Because of the different hydrothermal conditions, it resulted in significant differences in soil properties. In Riverland and streams land, as a small amount of evaporation, soil nutrient was more room for release, especially AP and AK releasing more visible. Ping land and sloping land had the light rainfall, strong evaporation, the capability of soil fertilizer and water was weak.(2) In the natural grass surface soil, OM, TN, AN, TK, AK and CEC content were the highest of the three grassland, their fertility significantly stronger than abandoned and Medicago sativa. In addition, forbidden grazing significantly improved the quantity of soil OM and CEC content, lower soil pH, promoted mineral elements into decomposition, increase available nutrient content. From the grazing to forbidden grazing pasture, soil TP, OM, AN, AK and CEC increased significantly, generally increasing by 25 %, CaCO₃ and TK content signifently increased; The increase and decrease in surface soil profile were more obvious increases of up to 50 %.(3) There was significant difference between Hippopgae Rhamnoides and Caragana. Soil AN, AK of Caragana land was two time of that of Hippopgae Rhamnoides land. And it reached between the two very significant difference; Soil surface AP of Hippopgae Rhamnoides forest land was higher than Caragana woodland, and the lower and middle classes of Hippopgae Rhamnoides forest land than Caragana forest land, But it did not reach the level of significant difference. Soil surface OM of Caragana land was higher than that of Hippopgae Rhamnoides forest land, and there was no significant difference between them; Soil pH, CaCO₃ and CEC, soil TN, TP and TK had little difference between them.(4) High forest on soil fertility was significantly stronger. The mixed of Prunus armemiaca and Hippopgae Rhamnoides, the improvement of soil surface OM was most significant, as high as 20.79 g/kg; The mixed of Prunus armemiaca and Populus simonyi and Populus simonii pure forest land, soil surface AN content increased considerably, and it reached 60 g/kg; The mixed of Populus simonii and Hippopgae Rhamnoides, and Prunus armemiaca pure forest, soil surface TN content was higher than others; The mixed of Prunus armemiaca and Populus simonii pure forest soil AK content had the more obvious changes. Grown-up Pinus tabulaeformis and Robinia psendoacacia and, soil OM content increased larger. Hippopgae Rhamnoide after middle age was recessed, its aggregate total declined.(5) Because of land use and vegetation change, soil enzyme activity changes there is a clear difference. In the soil surface, Urease activity of the Caragana forest land was strongest, followed by the high forest and Riverland; Alkaline phosphatase enzyme activity of the high forest was the highest, pure and mixed forest was 39.69 and 29.36 mg/g·d, followed by Caragana forest land and Riverland; the Invertase activity of pure and mixed forest was higher, at 27.72 and 23.27 mg/g·d, followed the riverland to be 27.25 mg/g·d and Caragana woodland to 21.35 mg/g·d, the enzyme activity of the others was relatively low. Enzyme activity showed decrease of top-down trend, it was with the increase of depth, microbial activity caused by the weaker.(6) Soil CEC: Grassland >high forest>farmland>brushland, between different types achieve significant difference, and the difference between different types was obvious, achieved very significant difference; Soil AN: Grassland and high forest>farmland>brushland. The soil TN content of farmlands and grassland was higher, the brushland TN was lower. Soil AP content between different forms used to a very significant difference, the farmland was far higher than in other types. Land use different between all sections have shown significant differences in the surface high, dropped down; Soil TK in different forms and levels of use varied between very small, grassland and farmland in higher, lower woodland. High forest soil quality and lawn times, the worst shrub land, the ecological environment should consider planting grass and natural vegetation restoration of the main.