海涂资源土壤盐分三维空间变异性及风险评价研究-土地资源管理专业毕业论文.docx

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5结论与讨论 37
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参考文献 42
致谢 .49
II
万方数据
Contents
I Introduction ’l
Background and significance 1
Background ‘1
Significance ·3
Literature review ··3
Literature review ofland resource evaluation ·3 Literature review of proximal soil sensing and digital soil mapping ‘5 Literature review of 3D geostatistic and its application ’7 Literature review of risk assessment on the saline land ·9
Main contents and aims ·10
Main contents lO
ofthe study ··10
Flowdiagram ofthe study ’1l
2 Site and methods - · - 13
Studyareaand sampling 13
Study method ‘13
Three-dimensional kriging 13
Linear mixed model and geometric anisotropic model 1 5
The empirical best linear unbiased predictor 16
-dimensional indicatorkriging 17
Cross validation 17
3 Pseudo three-dimentionai variation of soil salinaty 一19
Summary statistics ’19
The variograms ofthe residuals 。21
Cross validation and the predictions ·25
Mapping and the results ·26
Chapter summary ·‘27
4 Three-dimentionai variation and risk assessment of soil salinaty ·’29 Three·dimentional variation ofsoil salinaty ‘29 Summary statistics 29
The variograms ofthe residuals 30
Mapping and the results ‘32
III
万方数据
assessment ·34
Chapter summary ··37
5 Conclution and discussion 38
Conclution ··38
Possibility ofinnovation 40
Prospect ··40
References .42
Acknowledgments 49
IV
万方数据
摘要
随着工业化和城镇化的快速发展,我国耕地资源供需矛盾日益突出,不少经济发达的沿海省份将海涂区域看作重要的耕地后备资源。据统计,浙江省自建国以来海涂围垦面积累计就超过20万hm2,海涂资源围垦改造已然成为浙江省耕地占补平衡的重要手段。然而,新围垦海涂盐分高、返盐强烈,造成农业减产、甚至绝收。因此,开展海涂围垦区土壤盐分的空间变异特征及开发利用风险评价研究对于盐渍土资源的有效管理和农业的科学规划以及实现耕地保护“质”与“量”的并重发展都具有重要意义。
本研究以浙江省北部、杭州湾南岸的海涂围垦区为研究区域,基于电磁型近地传感器EM38快速获取批量水平和垂直模式下的土壤表征电导率数据,利用EC。线性响应模型,以土壤不同深度的电导率值作为研究的数据源,并基于此分别以“伪”三维、三维的地统计学方法进行数字建模,采用线性混合模型去除空间变化趋势,交叉检验评价各组合的模型精度,