采样密度对土壤有机质空间变异解析的影响  

Effect of sampling density on spatial variability analysis of soil organic matter

作　　者：范曼曼[1] 吴鹏豹[1] 张欢[1] 魏晓[1] 陈富荣[2] 高超[1] 

机构地区：[1]南京大学地理与海洋科学学院,江苏南京210046 [2]安徽省地质调查院,安徽合肥230001

出　　处：《农业现代化研究》2016年第3期594-600,共7页Research of Agricultural Modernization

基　　金：国土资源大调查项目(1212010310305)~~

摘　　要：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。Determination of a rational sampling density can facilitate revealing spatial variability of soil attributes efficiently, which is the premise of improving the accuracy of soil quality assessment. By using geographic information system （GIS） and geostatistics methods, this paper examined the effects of sampling density on spatial variability analysis of soil organic matter （SOM）. In the study area of Northern Hefei City in China, 6 data subsets （the corresponding sampling densities were 0.8 per km2, 0.56 per km2, 0.39 per km2, 0.28 per km2, 0.19 per km2, and 0.13 per krn2, respectively） were repeatedly selected for 20 times at random from the whole 5207 sampling sites for spatial variability analysis. The results indicated that the mean concentrations of SOM had no significant differences among various sampling densities, illustrating that sampling densities at different scales were all representative for the mean value of SOM. SOM in the study area exhibited a medium spatial dependence. The structural component was relatively high at the sampling density of 0.28 per km2, and did not increase evidently with further increasing sampling density. When the density was below 0.28 per km2, some partial detailed information was filtered and the characteristics of spatial variability could not be accurately expressed. With regarding to the natural geography and land use conditions in the study area, the optimal sampling density to detect SOM spatial variability is suggested to be 0.28 per km2 to evaluate soil fertility quality. If for estimating the potential capacity of soil carbon sink, then one sampling point per 22 km2 can be able to meet the requirement and acquire the expected effect.

关 键 词：土壤有机质 采样密度 普通克里格 地统计学 半方差函数 

分 类 号：S58[农业科学—作物学]