不同地形植烟土壤的合理取样数量分析

Rational Sampling Density of Tobacco-planting Soil Dependent on Different Topography

地形影响着精准施肥网格取样的间距,在烤烟高量磷、钾肥料投入背景下,为了确定不同地形植烟土壤的取样密度,分别在平原、开阔坝子地、狭窄坝子地、缓坡地4种主要地形的植烟土壤上进行了50 m×50 m网格取样和土壤速效养分测试。结果表明：采用Cochran公式,在置信水平90%,允许误差15%时,平原、坝子地、缓坡地的单样品代表面积分别为1.92,1.01～1.56和0.73 hm^2;采用地统计学方法得出的平原、坝子地和缓坡地精准养分管理最大网格取样间距分别为234.0,134.4～177.5和58.2 m。因此,地形条件由简单到复杂,取样密度应逐渐增加。

Topography influences the density of soil sampling points for precise fertilization. In the case of high phosphorus and potassium fertilization for flue-cured tobacco, the soils in areas of plain, broad valley, narrow valley and gentle slope were sampled by 50 m×50 m grids and the available nutrients in soil samples were tested. The results showed that by Cochran formula,individual sample for plain, valley and gentle slope represented an area of 1.92, 1.01-1.56 and0.73 ha, respectively at a confidence level of 90% and a relative error of 15%; by geostatistical method, the maximum sampling space for precise nutrient management were 234.0, 134.4-177.5and 58.2 m for plain, valley and gentle slope, respectively. It indicated that sampling densityshould be increased gradually from flat to slope.