苏北海涂典型围垦区土壤盐渍化风险评估研究
Evaluating soil salinization risk in typical coastal reclaimed regions in North Jiangsu Province
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摘要: 为定量评估制约苏北海涂土壤资源开发利用的盐渍障碍因素, 以苏北海涂典型围垦区江苏省大丰市金海农场为例, 将灰色系统理论应用于风险评价, 构建了实用的生态风险评价数学模型、指标体系与评价流程, 并对区域土壤盐渍化风险状况进行了定量评估与分级。结果表明: 土壤盐分、表土层容重与地下水矿化度是该区域盐渍化风险评估的重要因素; 研究区土壤盐渍化风险总体较高且不同部位差异较大, 其生态风险值F介于0.12~0.60之间, 平均值达0.30; 盐渍化风险分布表现出与土壤盐分、地下水矿化度较为相似的空间规律; 受种植制度与耕作措施差异的影响, 研究区东部水稻田盐渍化风险总体高于西部棉花地; 研究区域不存在土壤盐渍化较小风险区, 以一般风险、较大风险为主, 其中较大风险区占总面积的50.11%, 一般风险区占49.41%, 很大风险区仅占0.48%, 一般风险和较大风险区是该区土壤改良治理的重点区域。该结果可为海涂区中、低产地的质量提升、盐渍化土壤的科学改良与田间管理提供参考依据。Abstract: Salinization is a major obstacle for effective exploitation and utilization of soil resources in coastal regions of especially North Jiangsu Province. To that end, the gray relation theory was used to assess the risk of soil salinization in the farmlands of Jinhai Farm, Dafeng County. This is a typical region in North Jiangsu Province with extensive coastal land reclamation. A practical mathematical formula was designed to determine and classify risk evaluation index in the region. Results show that soil salinity, surface soil bulk density and groundwater mineralization are the most important drivers of salinization. For the farmlands of Jinhai, the range of ecological risk value (F) is 0.12~0.60 with an average of 0.30. This indicates that the risk of soil salinization is generally high and varies significantly with location in the study area. The spatial distribution of risk of salinization is similar to the distributions of soil salinity and groundwater mineralization. Due to differences in cropping and cultivation practices, the risk of salinization in rice fields is higher than that in cotton fields. While, there hardly exists low-risk regions, high-risk and medium-risk regions pervade across the study area. Areas of high-risk, medium-risk and severe-risk respectively account for 50.11%, 49.41% and 0.48% of total study area. Areas of high-risk and medium-risk need urgent amelioration measures. The findings in this study provide the basis for quality improvements in moderate-to-low-yield farmlands. It also lays the basis for scientific amelioration and management of saline soils in coastal regions of North Jiangsu Province.