Study On Spatial Variability Of Soil Nutrient And Sampling Number In Hill Slope

In recent decades, the research on the spatial variability of soil nutrients and site-specific nutrients management developed quickly and made great progress. However. The research in this field in China just started and lags behind the developed countries. Traditional agriculture often regards soil as symmetrical, uniform integer to deal with and ignores the variation of soil nutrient inside soil, so caused fertilizer insufficiently in some areas or fertilizer amply in the others field. This is not only caused the waste of the fertilizer but also constituted a threat to ecological environment, therefore the production efficiency and economic benefits are low. With sustainable agriculture's study furtherly maturing, modernistric computer technology, localization of the satellite and automatic control technology developing and perfecting, more and more people are awared that, every agricultural elements according to soil nutrient variation are optimized at the maximum exten to obtain the best outputs and the greatest economic benefits, and to protect agricultural ecological environments as the same time.Soil nutrient distribution map based on geographical information system technology has certain reference meanings for displaying soil nutrient variation rule and confirming the rational sampling number. Especially under the condition that it has a bigger difference among different areas in the field which soil nutrient makes a variation to some special areas, dividing soil region and distributing sampling number according to soil nutrient spatial variance, can reduce the cost and improve the efficiency of taking a sample. Sampling number of all kinds of soil nutrient need have certain differences under certain precision and allowed error terms. In practical application, the best quantity of comprehensive sample is confirmed according to weigh the important degree of different elements and analysis purpose and task.This research using geostatistics method to study spatial variability of soil at the town of wutan in Jiangjin, sampling point of soil characteristic was analysed by Cochran (1977) formula, and points out precision choosing and the choice of rational sampling number under certain believable level. This research also combines combined the geostatistics method and interpolation of Kriging to verified whether the sampling point are reasonable or not, the content and result are as follows:(l)Soil characteristic data's treatment and basic statistics. The differential value of soil characteristic has been identified by extent range, replacing differential value with normal maximum or minimum value. Statistical analysis shows that: Coefficient of variation of soil characteristic between 6.09% into 66.67% belongs to the mid-intensity variability. Coefficient of variation of the testing value of B is the greatest; The variability of P , Cu , Fe , Zn takes second place, respectively is 37.96%, 34.08%, 27.54%, 26.00%; the coefficient of variation of the testing value of OM, N , K,...