论文部分内容阅读
确定合理的采样密度以便更有效地揭示土壤属性的空间变异,是提高土壤质量评价工作准确性的前提。本文以合肥市北部地区为例,从5 207个土壤采样点(采样密度为1个/km2)中重复20次随机抽取不同采样密度的六个样本子集(对应采样密度分别是0.8个/km2、0.56个/km2、0.39个/km2、0.28个/km2、0.19个/km2、0.13个/km2),采用地理信息系统(GIS)技术和地统计学方法,研究采样密度对土壤有机质(SOM)空间变异解析的影响。结果表明:上述不同采样密度下,有机质含量的均值差异不显著,各样本对总体均具有较强的代表性。土壤有机质表现出中等的空间相关性,采样密度为0.28个/km2时探测到的SOM含量变异结构中结构性组分比例最高。采样密度小于0.28个/km2时,则局部细节信息被过滤,不能准确充分地表现其空间变异特征。在研究区的这种自然地理条件和土地利用方式下,若评价目的主要针对土壤肥力质量,揭示土壤有机质空间变异的最佳采样密度应为0.28个/km2。若是针对区域土壤碳汇潜力,则大约22 km2布置一个采样点即可获得预期的效果。
Determining a reasonable sampling density in order to more effectively reveal the spatial variability of soil properties is to improve the accuracy of soil quality assessment work premise. Taking northern area of Hefei as an example, six sample subsets with different sampling densities were sampled randomly from 5 207 soil sampling sites (sampling density 1 / km2) for 20 times (corresponding sampling density 0.8 / km2 , 0.56 / km2, 0.39 / km2, 0.28 / km2, 0.19 / km2, and 0.13 / km2). Using GIS and geostatistics methods, Impact of Spatial Variability Analysis. The results show that there is no significant difference in mean value of organic matter content among the above sampling densities, and each sample has a strong representation of the whole population. Soil organic matter showed a moderate spatial correlation, and the highest proportion of structural components in the SOM content variation structure detected at a sampling density of 0.28 / km2. When the sampling density is less than 0.28 / km2, the local detail information is filtered and the spatial variation feature can not be accurately and fully expressed. Under such natural geographical conditions and land use types in the study area, if the evaluation purpose is mainly aimed at the soil fertility quality, the optimal sampling density to reveal the spatial variation of soil organic matter should be 0.28 / km2. For the potential of regional soil carbon sequestration, a sampling point of about 22 km2 will provide the expected results.