Study On Soil Water Content And Soil Fertility Dynamics Of Caragana Microphylla On Loess Plateau In North-west Of Shanxi Province

The hilly Loess Plateau in North-west of Shanxi province is one of the most serious soil erosion in Loess Plateau, the ecological environment is extremely bad. For the windproof, water and soil conservation and the development of animal husbandry, a large area of Caragana microphylla was planted in the hilly Loess Plateau in North-west of Shanxi province on the 1960s. Due to the lack of water in the area, the poor soil and poor management, shrub soil quality changes directly related to the effect of vegetation restoration and sustainable production capacity. This article used the method which in the open country sampling investigation and the room analyzes unifies, the experiments was conducted to study soil water and soil fertility dynamics of Caragana microphylla at different growing years (5, 10, 20, 30, 40) on Loess Plateau in North west of Shanxi .Such a study could be able to provide a theoretical basis for the grain for green project and vegetation restoration.1. The experiment was conducted to study soil water dynamics in different growing years of Caranaga microphylla. The results showed that soil water content was affected by precipitation and plant growth, the change was big. From the vertical distribution(0～2m depth), the 5-years-old Caragana microphylla profile of soil water content had decline firstly after an upward trendency, and the 10-years-old, 20-year-old and 30-years old, 40 years old soil water content showed a gradually decreasing tendency. Soil water content of Caragana microphylla in the year seasonal variations was continued depressing from April to June in a year, the lowest point presence in June and July, and then gradually increased from August to October with the subsequent precipitation increasing.2. The experiment was conducted to study soil fertility dynamics in different growing years of Caranaga microphylla. The results showed that soil physical and chemical properties in Caragana microphylla plantation were all well improved with the age increasing, soil bulk density decreased, soil porosity, saturated water holding capacity and water permeability improved. The content of soil organic matter and total N showed gradually increasing tendency, which were highest in 30-age plantation, while Olsen P and available K largely decreased. With the increasing of the growing years, the content of soil total P was not obviously changed and the content of soil total K was not very significantly changed expect for 10-age plantation maximum. Meanwhile, the soil enzyme activities in Caragana microphylla plantation were enhanced with the growing years increasing, and the soil enzyme activities in 20-age plantation were the highest.3. The experiment was conducted to study soil Rhizosphere effect in different growing years of Caranaga microphylla. The resulted that there was an obvious rhizosphere effect in all growing years of Caranaga microphylla plantation. The pH value of rhizosphere soil was lower than those of near rhizoshphere soil at different growing years. The content of organic matter, total N and available K in rhizosphere soil were all higher than those in near rhizoshphere soil, but the content of Olsen-P in 5-age plantation was remarkably deficient in rhizosphere soil. The Peroxidase activity of rhizosphere soil in different growing years were all higher than those in near rhizosphere expect for in 20-age plantation, while Alkaline phosphatase activity of rhizosphere soil were lower than those in near rhizosphere expect for in 10-age plantation.