东北黑土地区主要土壤肥力质量指标的空间变异性

采用地理信息系统(G IS)和地统计学相结合的方法研究了本世纪初东北黑土区土壤表层(0~20 cm)pH、有机质、速效磷、速效钾、粘粒这5种土壤肥力指标的空间变异性。结果表明:土壤pH和粘粒的理论模型均为指数模型;有机质、速效磷和速效钾的理论模型均为球状模型。速效磷、速效钾的C0/(C0+C)较大,为46.63%和49.91%,说明这2种肥力指标具有中等的空间相关性;而pH、有机质、粘粒的C0/(C0+C)分别为10.80%、16.57%、12.88%,说明这3种肥力指标具有较强的空间相关性。根据每个采样点的指标数据计算出该地区土壤肥力质量综合评价指数,最终得到研究区土壤肥力质量的分布图。

Spatial Variability of Soil Fertility Quality Indices in Northeast China

Geographical information system(GIS) combined with Geostatistics was applied to reveal the spatial variability of soil fertility quality indices i.e.,soil pH,organic matter,available P,available K and clay in the topsoil (0~20cm) in the northeastern area of China.The results showed that theoretical semivariogram models of soil pH and clay were best described with an exponential model,whereas the organic matter,available P and available K were best fitted with a spherical model.The ratios of nugget to sill of available P and available K were 46.63%,49.91%,respectively,indicating that the spatial correlation of the two fertility indices was moderately dependent.The ratios of nugget to sill of pH,organic matter and clay were 10.80%,16.57% and 12.88%,respectively, indicating that the spatial correlation of the three fertility indices was strongly dependent.The integrated index of soil fertility quality was calculated based on each sample index,then from the spatial distributed map of soil fertility quality we could get the integrated index in the region.