黄河三角洲盐碱地混交林土壤电导率的空间异质性

Spatial heterogeneity of soil electrical conductivity in a mixed plantation of the Yellow River Delta saline land

为了研究黄河三角洲盐碱地混交林土壤盐分在旱季和雨季的空间分布特征,以黄河三角洲新造的由11个树种组成的混交林为研究对象,利用经典统计学和地统计学相结合的方法,绘制上层（0 ～ 15 cm）和下层（15～30 cm）土壤电导率的随机性和结构性的半方差图以及空间分布图,研究春季和秋季不同深度土壤电导率的空间变异特征.结果表明：1）土壤电导率平均值在春季和秋季有显著差异,不论是上层还是下层,春季均大于秋季.春季上层和下层土壤电导率变化范围分别为1.12 ～5.18和0.83～3.72 mS/cm,变度分别为4.06和2.89 mS/cm.秋季上层和下层土壤电导率变化范围分别为0.85 ～2.91和0.62～3.05 mS/cm,变度分别为2.06和2.43 mS/cm.春季土壤电导率变异系数较大,而秋季则较小.2）春季混交林上层和下层土壤电导率均有强烈的自相关性,变程分别为13.47和12.72 m.秋季上层和下层土壤电导率变异函数的半方差图几乎为直线,变程分别为213和71m,超出了取样范围,表明在该取样尺度下没有自相关性.3）Kriging插值结果表明,混交林地春季土壤电导率斑块化程度高于秋季.

In order to study the spatial distribution characteristics of soil salinity in mixed forest of Yellow River Delta saline land,a new mixed plantation composed of 11 species in Yellow River Delta was taken as the object.The spatial variation of soil electrical conductivity in different seasons and different soil layers （0-15 cm and 15-30 cm） was measured and analyzed by traditional statistics and geostatistics.The spatial distribution maps and semi-variograms charts could explicitly explain the random and structural variations of soil electrical conductivity.Results showed that：1）The mean value of soil electrical conductivity in spring and autumn had a significant difference,and the mean value,either in the upper layer （0-15 cm） or in the lower layer （15-30 cm）,was larger in spring than in autumn.In spring,the range of soil electrical conductivity in the upper layer was 1.12-5.18 mS/cm with an amplitude of 4.08 mS/cm,and that in the lower layer was 0.83-3.72 mS/cm with an amplitude of 2.89 mS/cm.In autumn,the range of soil electrical conductivity in the upper layer was 0.85-2.91 mS/cm with an amplitude of 2.06 mS/cm,and that in the lower layer was 0.62-3.05 mS/cm with an amplitude of 2.43 mS/cm.The coefficient of variation in spring was larger than that in autumn.2） In spring,soil electrical conductivity in both the upper and the lower layers had a strong autocorrelation.In autumn,there was no autocorrelation for the soil electrical conductivity neither in the upper layer nor in the lower layer,with an amplitude of 213 m and 71 m,respectively,both exceeding the sampling area.3）Kriging interpolation indicated that the patchiness of soil electrical conductivity in spring was more serious in comparison to that in autumn.