宁夏盐池县防沙治沙区土壤粒度、SOC及TN的空间异质性

Spatial Heterogeneity of Grain Size, SOC and TN in Areas of Desertification Combating of Yanchi in Ningxia

为了探究宁夏盐池县实施防沙治沙措施后风沙土粒度特征变化对其防沙治沙区生态环境恢复的指示作用,以该区王乐井乡作为研究对象,通过野外采样及室内试验,分析了沙漠化治理区土壤粒度、土壤有机碳(SOC)及土壤全氮(TN)的空间分异特征及其相关性。结果表明:该区域风沙土优势粒级是细沙,各粒级均表现为中等变异,中沙和粉沙体积分数较低,变异性最高,细沙和极细沙变异系数较低;极细沙、粉沙、中沙和SOC、TN均表现出强烈的空间自相关,主要受结构性因素影响,而细沙具有明显的空间自相关,受结构性因素和随机性因素共同影响;粉沙体积分数空间分布表现为从北向南逐渐增加,极细沙体积分数表现为从北向南减少,细沙体积分数最高,空间特征呈明显带状分布,从北向南减少;SOC在空间上分布与TN有较高的相似性,受地形影响较明显,总体表现为西北角较低,东南角较高。随着粉沙增加,TN表现出上升趋势,粒度组成对SOC的影响特征与TN相似,但是变化趋势较缓慢。该区域风沙土粒度、SOC、TN具有明显的空间分布特征,粉沙体积分数对SOC和TN影响较为显著。

With the desertification combating areas of Yanchi in Ningxia, by the field investigation and laboratory analysis, the statistical analysis method was used to study the spatial heterogeneity of grain size and spatial correlation analysis with SOC and TN. The dominant particle size is fine sand and very fine sand. The spatial distribution of silt sand was gradually increased from north to south and the very fine sand was gradually decreased from north to south. The spatial characteristics showed obvious zonal distribution. The medium sand content was lowest. The spatial distribution of SOC had a high similarity with the total N, and was significantly affected by the topography. And the overall expression was that the content in the northwest corner was low and that in the southeast corner was high. As the percentage of silt sand content increased, the content of total N showed an upward trend. The influence of particle size composition on SOC was similar to that of total N, but the change trend was slow. This study verified that the effect of aeolian sand deposition on the spatial distribution of nutrient elements in the region scale, and the results showed that the change of aeolian soil particle composition had an indication effect on the ecological environment of this region since the implementation of measures to control desertification. The grain size, soil SOC and soil TN of wind-sand soil in this region have obvious spatial distribution characteristics, and the silt content has a significant impact on soil SOC and TN, indicating that soil properties are gradually changing in the process of desertification combating in this region.