毛乌素沙漠-黄土高原过渡带土壤养分空间异质性

毛乌素沙漠-黄土高原过渡带土壤养分的空间异质性和生态学过程,对沙荒地整治的机理研究具有重要的意义。以毛乌素沙漠-黄土过渡带为研究区,结合布点取样和室内分析,运用经典统计学和地统计学方法对其全氮、有效磷、速效钾含量的空间异质性进行分析。结果表明,(1)土壤全氮、有效磷、速效钾的平均含量分别为0.39 g/kg、9.65 mg/kg和106.84 mg/kg。3种养分的变异系数为40.54%—84.62%,均属于中等程度变异,其中全氮变异系数最大,速效钾变异系数最小。(2)半方差分析结果显示,3种养分空间变异性的最佳拟合模型均为高斯模型,空间自相关性均随着滞后距离的增加而呈下降趋势。3种养分空间变异性的块金值/基台值比值在0.09%—32.82%,全氮、有效磷具有强烈的空间相关性,结构性因素对变异起主导作用;速效钾具有中等强度的空间相关性,结构性因素和随机性因素共同对变异起主导作用。(3)克里金插值图显示3种养分含量均表现为随着地势的降低而逐渐升高的趋势,全氮含量整体呈斑点状分布,插值图较破碎,有效磷和速效钾含量整体呈条带状分布,连续性较好。(4)毛乌素沙漠-黄土过渡带土壤养分的空间变异性与地形、地貌、植物分布以及非自然因素都有关,但是以地形因素的影响为主。开展沙漠-黄土过渡带土壤养分空间异质性特征研究,为开展沙荒地整治工程,生态系统修复提供了理论依据。

Soil nutrient spatial heterogeneity in the Mu Us Desert-Loess Plateau Transition Zone

Studies on the spatial heterogeneity of soil nutrients in the Mu Us Desert-Loess Plateau Transition Zone will improve our understanding of the mechanisms driving land desertification. We investigated the spatial variability characteristics of three soil nutrients in the Mu Us Desert-Loess Plateau Transition Zone by using semivariogram analysis and the ordinary kriging method.The results indicated that the average total nitrogen (N), available phosphorus (P), and available potassium(K) contents were 0.39 g/kg, 9.65 mg/kg, and 106.84 mg/kg, respectively. Total nitrogencontent had the largest variation coefficient range (40.54%-84.62%), whereas K had the smallest.The semivariogram analysis showed that the content variations for all three nutrients were the best described by a Gaussian distribution model and that the spatial autocorrelations decreased as the distance increased.The (C₀/C₀+C) ratios were 0.09%-32.82%for the three soil nutrients.The N and P contents showed strong spatial autocorrelation, but the K contents only showed a modest degree of autocorrelation. The ordinary kriging method was used to estimate unmeasured points and interpolation maps were obtained. All threesoil nutrient contents were more concentrated on the lower terrain. Total nitrogenhad a scattered "fertile islands" distribution, whereas P and K had a banded, continuous distribution. The heterogeneity of the soil nutrients in the Mu Us Desert-Loess Plateau Transition Zone was influenced by terrain, landscape, plant distribution, and other non-natural factors, but the terrain had the highest impact. From a practical application perspective, this study provides a theoretical basis for future land engineering and ecosystem restoration programs.