浙中丘陵盆地区1∶5万土地质量地球化学调查方法研究
Research of 1∶50,000 Land Quality Geochemical Survey Technique at A Hillybasin Area in Zhejiang Province

摘要： 摘要：以1∶5万土地质量地球化学调查成果服务于土地精准管理为目标，在浙中丘陵盆地选择金华市汤溪镇地块细碎的典型区域，开展了两种采样密度的对比研究：(1)按1∶5万土地质量地球化学调查的采样密度上限采样，平均采样密度164件/km2，采用克里金插值法进行图斑赋值(下文简称插值)；(2)以土地精准管理为目标，以地块为单元采样，平均采样密度1795件/km2，用实测值对图斑赋值(下文简称实测)。以图斑为评价单元，对比上述两种方法间元素含量、土壤环境及养分指标分级、土壤质量综合分级的差异。研究表明：(1)与土壤质量评价密切相关的15项指标中，有9项指标插值与实测值元素含量的相对双差合格率达到90%，4项指标接近90%，仅2项指标合格率低于80%；(2)插值与实测值的土壤环境单指标分级与环境指标综合分级结果极为接近，养分指标分级差异略大；(3)实测值与插值土壤质量综合分级一级、二级图斑数所占比例相差118%，图斑面积相差74%，约40%的图斑土壤质量综合等级发生变化。研究区内环境指标变异性较小，插值与实测值的评价分级结果基本一致；养分指标N、P、K的空间变异较强，是导致插值与实测值土壤质量综合分级差异的主要原因。以上结果表明，浙中丘陵盆地区1∶5万土地质量地球化学调查成果对土地利用规划、科学平衡施肥等具有重要价值，但其成果精度尚难满足土地精准管理的需要。
Abstract: Abstract: A research on the technique of 1∶50,000 land quality geochemical survey at a hillybasin area in central Zhejiang Province was carried out at 2014. The experimental procedure was as follows：(1)using the upper limit of sampling density of 1∶50,000 land quality geochemical survey, the average sampling density is 164 samples per km2, Kriging interpolation method is used for the patch assignment (hereinafter referred to as interpolation);(2)to reach the target of precise land management, use the land plots as sampling units. The average sampling density is 1795 samples per km2.Then use the measuring results in the patch assignment (hereinafter referred to as measured). Several parameters, including element content, geochemical grade of soil environment, geochemical grade of soil nutrient and geochemical comprehensive grade of soil quality were compared respectively in 16 samples per km2 and 180 samples per km2. The study showed that: (1) by studying the relative deviation (RD) between interpolation and measured value of 15 elements which are crucial in the land quality assessment, we found that the RD qualified rate pass 90%, 80% to 90%, under 80% were separately 9,4 and 2; (2) the difference between interpolation and measured value in single geochemical grade of soil environment and comprehensive geochemical grade of soil environment are quite small, while it was more distinct in geochemical grade of soil nutrient; (3) the proportions of number and area change between interpolation and measured value for the first and second grade patches are 118% and 74%.The comprehensive geochemical grade of soil quality has changed in about 40% of the patches. In the experiment plot, the RD between interpolation and measured value were mainly caused by the spatial difference of N, P, K. The research shows that, the results of 1∶50,000 land quality geochemical survey, in a word, according to the land quality geochemical assessment requirements, can provide the