Research On Land Use Types Of New-reclamated Soil And Change Of Soil Quality In Arid Zone

The objective of the thesis was to study the spatial temporal changes regulation under different land uses and evaluated the effect of different land uses on soil physical and chemical quality in the agricultural exploitation area of Kelamayi. It was based on the field-investigated data and the analyzed results in laboratory. The results showed: (1) Rotation of alfalfa and cotton was obvious on soil quality by analyzing the spatial change of land use and soil physical, chemical characters in 2001 year of reclamation Rotation of melon-cotton could increase the content of soil available N and improve soil pH. Farmlands for one-crop system was obvious to increase soil p and k content in the soil surface level, but could not improve soil organic matter and N content. The plantation could certainly improve the soil quality in 60-100cm depth, but the soil quality was worse in 30cm depth. The manmade grasslands could improve soil N content, however, the effect was worse on soil p and k. (2) Through analyzing the soil quality change of the farm land and forests in different years of reclamation, we knowed that it could not improve efficiently soil quality for one-crop system (3) the average values of soil organic matter, total N content are less than that of the available N and P content and the available K content is the most of all. The statistical results are that the variation of available p is the most of all. The total P, K, bulk density values were little variable compared to the available N, K, organic matter and the total N content; pH value is the lest variable.(4) the results of principal component analysis of soil nutrients reveal that the contribution ratio of the first, second, third and fourth principal component is 72.48% as a conclusion of the soil quality. The first principal component mainly represents the soil basic fertility index, The seconds reflects the soil p and k, The third and fourth reflect the soil physical characters. (5)By dividing the soil grade under the different land use, the soil quality was rotation of alfalfa-cotton > rotation of melon-cotton >farmlands > the manmade grasslands >the plantation> the wilds. Moreover, suitable measures were put forward for different soil plant types.