干旱荒漠区人工绿洲土壤盐碱化风险综合评估与演变分析

Comprehensive assessment and evolution analysis of soil salinization in artificial oasis in arid desert area

为明晰干旱荒漠区人工绿洲水盐时空分异特征与盐碱化风险空间格局演变过程,以甘肃省景电灌区为研究区,以2002,2010及2018年为研究代表年,基于多级模糊理论从地质气候驱动、水土环境驱动和自然-人类驱动3个驱动过程构建土壤盐碱化风险评估体系,集成云发生器原理、黄金分割率法、组合赋权法以及排队理论构建土壤盐碱化空间风险综合评价模型.将长序列监测数据、多时相空间数据以及经济社会数据依据各驱动要素权重以ArcGIS10.2为技术平台进行多源融合,对各空间风险状态进行了空间可视化表达与流向追踪.结果表明:1)研究区2002,2010及2018年土地盐碱化整体风险分别为“临界状态”、“临界状态—轻度风险”、“轻度风险”;2)地下水埋深及地下水矿化度是驱动土壤盐碱化进程加剧的主导因素;3)灌区盐碱化空间风险演变模式剧烈程度排序为持续变化型>前期变化型>后期变化型>持续稳定型>反复变化型.研究区盐碱化整体风险状态呈现出由“无风险—临界状态”以及“临界状态—轻度风险”过渡的趋势;4)2002~2018年间研究区盐碱化空间风险整体呈升级态势,表征出明显的地区差异性且总体呈现由西北向东南以弧射状增高的空间格局.

To clarify the spatiotemporal variation characteristics of water and salt and the spatial evolution of salinization in artificial oasis in arid desert area,Jingtaichuan electric power irrigation area in Gansu Province was taken as the research area,2002,2010 and 2018 were selected as representative years.The soil salinization risk assessment system was constructed based on multi-level fuzzy theory from three driving processes:geological-climatic driven,soil-water environmental driven and natural-human driven.The cloud generator principle,golden ratio method,combined assignment method and queuing theory were integrated to construct a comprehensive spatial risk evaluation model of soil salinization.The long-sequence monitoring data,multi-temporal spatial data,and economic and social data were fused based on the element weights using ArcGIS10.2.The spatial risk state of salinization in each period was visually expressed and flow traced.The results of the study showed that:1)The overall risks of land salinization in 2002,2010 and 2018 were"critical","critical-mild risk"and"mild risk";2)The dominant factors in the soil salinization were the depth of groundwater and the mineralization of groundwater;3)In the irrigation area,the intensity of spatial evolution pattern of salinization risk:continuous change type>early change type>late change type>continuous stable type>repeated change type.The overall salinization risk in the study area showed a transition trend from"risk-free to critical state"and"from critical state to mild risk";4)From 2002 to 2018,the salinization in the study area was aggravating with obvious regional differences and generally presented an arcing increase from northwest to southeast.