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通过对仪征市第二次全国土壤普查1、994年土壤普查2、000年土壤养分调查、2005年农业部测土施肥试点土壤养分数据,应用地统计和GIS技术进行时空变异特征分析,研究结果发现:20年间大部分土壤养分都具有良好的半方差结构,土壤速效钾的变化分2个变化时期,前期减少后期增加,以1994年为分水岭;土壤pH呈略为的下降趋势;速效磷平均含量不高,变化不明显;有效锌含量比较稳定平均含量在1.0mg/kg;有机质含量呈稳定的上升趋势,平均每年增加3.0%。在本研究区域内,除了有效锌,其他土壤养分均存在一定的显著性差异,运用Cochran公式对研究区域样本容量进行估计,结果表明:研究区域范围土壤养分5%~10%的相对误差和95%置信水平条件下,能满足农业部测土配方施肥的精度,合理取样数量分别为:pH 26个、有机质199个、速效钾52个、速效磷410个、有效锌310个。
By analyzing the second national soil survey in Yizheng City, the soil nutrient survey in 2000 with the soil survey of 2000, the soil nutrient data in 2005 by the Ministry of Agriculture, the geostatistical and GIS techniques were used to analyze the characteristics of spatio-temporal variations. The results The results showed that most of the soil nutrients had a good semi-variance structure in 20 years. The changes of available potassium in soil were divided into two periods: the change of soil available potassium and the increase of sediment in late stage, and the change of soil pH was a slight downward trend. The average content of available phosphorus Not high, the change is not obvious; effective zinc content is relatively stable average content of 1.0mg / kg; organic matter content showed a steady upward trend, with an average annual increase of 3.0%. In the study area, in addition to available zinc, there are some significant differences in soil nutrients, using Cochran formula to estimate the sample size of the study area, the results showed that: the relative error of soil nutrients 5% ~ 10% of the study area and 95 % Confidence level, it can meet the accuracy of soil testing and formula fertilization of Ministry of Agriculture. The reasonable sampling quantities are: pH 26, organic matter 199, available potassium 52, available phosphorus 410, and available zinc 310 respectively.