Study On The Farmland Shelterbelt And Soil Physical And Chemical Properties Of Duobagou Oasis In Gansu

In this study, the trees grow,soil science theory have been taken as the foundation, full consideration to its own characteristics over the Duobagou oasis have been given, around the main line of the oasis in development time, using survey research, quantitative analysis, mathematical statistics and so on, the development and evolution of Duobagou oasis have been Expatiated from characteristics of oasis development, soil physical and chemical properties,oasis forestry and growth conditions of shelter forest. Main research shows that:(1)The growth condition of Farmland Shelter-belt built with two kands poplar which are Populus tomentosa Carr and Populus gansuensis C. Wang et H. L. Yang are very well in Duobagou oasis; at the initial growth, the height growth, diameter growth or volume growth of Populus tomentosa Carr is better than Populus gansuensis C. Wang et H. L. Yang, but at the later growth, it was to the contrary. In the 0～28a, The maxima height year after year growth of Populus gansuensis C. Wang et H. L. Yang was 2.44m/a, appears in the section 8a; Populus tomentosa Carr height growth year after year maxima height was 2.37m/a, appears in the section 6a, Two Poplar varieties of fast growing high-growth period concentrated in the former 9a; Populus tomentosa Carr 8a diameter growth in a maxima 50.1mm/a, Populus gansuensis C. Wang et H. L. Yang 12a diameter growth in a maxima 60.2mm/a, Populus gansuensis C. Wang et H. L. Yang from 8a into volume fast-growing period, volume year after year growth of maxima 0.327m3/a appear in the section 27a, Populus tomentosa Carr 5a entering volume from fast-growing period, volume year after year growth of maxima 0.208m3/a appear in the section 26a.(2)The surface soil in Duobagou Oasis was sandy loam soil. during different times in the surface of land mechanical composition content of the particle size, the coefficient of variation of particle content was between 0.04 to 0.31.However, during the reclamation of land in different particle size particle content of each diameter class level atα=0.05 significant difference, with the cultivation time increased use of soil to the fine development.(3)The surface soil in Duobagou was alkaline, human activities on soil alkaline in Duobagou has some amelioration, and in the development and utilization of the time with the growth of cultivated land, soil pH value decreases. Duobagou land surface soil available N,P,K and organic matter content were 21.94mg/kg, 8.38mg/kg, 150.42mg/kg, 7.33g/kg respectively, the surface were higher than those in the bottom layer.