Study On Variability Of Soil Fertility--Taking Fukang As An Example

A Study on the Soil fertility Variation Rules in the Arid Area---Taking Fukang as an ExampleSoil, as one of indispensable natural resource for human beings to rely on, the quality of soil concerns the sustainability of the ecological system, natural resources and the environment. With the increasing conflicts among population, resources and environment and people's in-depth research into the essences of the soil, the soil quality and its variation rules have been under heated discussion by the scholars and the government policy-makers worldwide.The arid area is both the major production area for food supplies, forestry and livestock and the ecological barrier in north China. Nevertheless, it has become a prominent conflict in the arid area that the negative effects human beings' activities acted upon the environment generally resulted in the conspicuous deterioration of the ecological environment, especially that of soil fertility. As a result, the research on the rules governing the variation of the soil fertility enjoys a strategic significance.The Geostatistic method can be used to assess the distribution of the soil attributes, to ascertain the space scale and the forms of the soil variation in order to improve the effectiveness of the sampling, and to research various of processes that caused such variations. At present, the application of the Geostatistic approach remains still the trend for the quantitative study on the soil space variation rules within and without China. With the wide application of GIS and the rapid development of the geological subject, the analysis on the space variation rules of the soil attributes in accordance with the Geostatistic model in the GIS software has become a hot topic in the agrological research. However, the present study on the rules of the soil space variation concentrates more on its physical aspects than its chemical attributes. In addition, most of the researches have focused the subjects found in the north plain areas whereas the research on the soil space variation has just turned on a new page. By adopting a Geostatistic method with the GIS software as an aid, the author mainly researched the space variation rules of 13 soil fertility elements in Fukang such as the organic composition, nitrogen, phosphor and kalium, …etc. The research area is a mountain-desert-oasis physiognomic unit, typically a subject of the arid area with a distribution of a variety of soil types such as mountain ice terrain, sub-mountain meadow, forest, meadow, desert, semi-desert and the oasis agricultural soil.The result of the analysis shows that a) the variation parameters of the soil fertility lie between 5.001%-121.81% with an approximately normal distribution of other major soil fertile indexes except for the salinity; b) the 13 soil fertility elements are all characterized by a space variation structure; c) the ratio by sill to nugget of other fertility elements nearly keeps ranging from 25% to 75% with a medium space correlation, the variation of which resulted from a co-working of the structural factors with random factors; the theoretical model of variation functions can achieve a distribution figure for different soil fertility elements and provide a panorama for the fertility and sterility of the soil by adopting a normal Kriging method for the optimum interpolation and portraying a space distribution pattern for various of soil fertility indexes.A relevant analysis also shows that the four microelements such as total nitrogen,organic composition, instant nitrogen, are apparently positively correlated and co-worked. The organic composition tends to correlate with the microelements, likely, the effective nitrogen, Cu, Fe, Zn and Mn. Using Geostatistices and Multistatistics to study the spatial variability of soil nutrient in arid areas, Which could make for better understanding the law more precision and directly in investigation spot, to guide the sampling plan and ascertain the sampling density, to set basis of interpolating or mapping , to build up compl...