Soil Taxonomy And Land Potential Productivity In Hotan Development Zone, Xinjiang

This study aimed to determine soil position in Chinese Soil Taxonomy through examining the physical and chemical properties of the different typical soil profiles in 220km2 land of Hotan Development Zone, Xinjiang. Diagnostic layer and diagnostic characteristics were identified according to《Chinese Soil Taxonomy(3rdedition)》. In this foundation, using the law of potential weaken we separately estimate the land potential productivity of the different soil type. In the estimate land potential productivity process determination the moisture and the soil correction coefficient is vital to obtain the correct result. In the study of moisture correction coefficient, we do not consider the influence of the soil type and only consider the influence of corps, precipitation and irrigation to the moisture correction coefficient. Finally we determine the moisture correction coefficient under the natural precipitation condition and the non-full irrigation condition. In the study of soil correction coefficient, we analyze soil nature and the agricultural resources condition and according to soil type determine the index weight of 7 item soil target in order to study the soil correction coefficient.The result show:(1) According to《Chinese Soil Taxonomy (3rdedition)》, there are aridic epipedon, ochric epipedon, salic horizon, gypsic horizon, cambic horizon and aridic moisture regime in the soil profile of Hotan development zone. So the soil of development zone should be characterized as Typic Gypsi-Orthic Aridosols, Typic Aridi-Orthic Halosols, Typci Hapli-Aridic Cambosols and Parasalic Aridi-Sandic Primosols in Chinese Soil Taxonomy.(2) Because difference of the soil type, soil correction coefficient is different. When we estimate the land potential productivity of Typci Hapli-Aridic Cambosols, the soil correction coefficient is 0.4914, but in Typic Gypsi-Orthic Aridosols and Parasalic Aridi-Sandic Primosols the salt content is high. So in this two type soil, the soil correction coefficient only is 0.1161 and 0.1269. Because high salt content in Typic Aridi-Orthic Halosols plant nearly does not live, we must first improve it before using the soil.(3) The potential productivity of photosynthesis, of the light and heat, of the light, heat and water has nothing to do with the soil type. The potential productivity of photosynthesis in Hotan is higher than the region with the same latitude , the potential productivity of photosynthesis of spring corn, spring wheat, winter wheat and cotton is 50 824 kg/hm2,45 177 kg/hm2,62 118 kg/hm2 and 56 471 kg/hm2 , the potential productivity of light heat is 21 304 kg/hm2,18 442 kg/hm2,25 528 kg/hm2 and 23 207 kg/hm2. Under the non-full irrigation condition the potential productivity of light, heat, water and soil of spring corn, spring wheat, winter wheat and cotton in Typci Hapli-Aridic Cambosols is 5 057 kg/hm2,5 560 kg/hm2,6 433 kg/hm2 and 6002 kg/hm2; in Parasalic Aridi-Sandic Primosols the potential productivity of light, heat , water and soil of spring corn, spring wheat, winter wheat and cotton is 1 306 kg/hm2,1 436 kg/hm2,1 661 kg/hm2 and 1 550 kg/hm2.(4) In the development zone under the natural precipitation condition, the climate potential productivity of grassland is 1 221 kg/hm2 (dry matter quality), the potential productivity of light, heat , water and soil in Typci Hapli-Aridic Cambosols and Parasalic Aridi-Sandic Primosols respectively is 154.94 kg/hm2 and 599.99 kg/hm2; Under the non-full irrigation condition the potential productivity of light, heat , water and soil of artificial grassland in Typci Hapli-Aridic Cambosols and Parasalic Aridi-Sandic Primosols is 1 215 kg/hm2 and 5 143 kg/hm2.On the basis of this, we put forward the suggestion of soil development and using. Typci Hapli-Aridic Cambosols first should do soil improvement and improve soil fertility before using. Because arid and few rain, the ecological environment of development zone is frail, therefore environmental conditions and soil fertility should be gradually improved in Typci Hapli-Aridic Cambosols. firstly we should create a wind shelter-belt and improve the ecological environment. Meanwhile we should plant forage and green manure as the main means of fertilizing the soil and improve the irrigation and drainage systems. It must be avoided to blindly exploit.