镇域重金属超标农用地安全利用调控研究

发布时间：2018-11-05 09:57

【摘要】：目前,土壤重金属污染隐形地影响了乡镇农用地的数量质量和农产品的安全,而且可能会对人们的健康造成威胁。因此开展关于镇域重金属超标农用地的安全利用调控研究,能够为乡镇尺度合理的利用和保护农用地提供很好的借鉴。本文首先基于CLUE-S模型预测出A镇未来的土地利用空间布局;以集成的重金属超标农用地安全利用评价标准为基础,对A镇重金属超标情况进行评价,采用地类转换的方法确定中、重度超标程度农用地的安全利用方向;基于安全利用评价结果和模型预测结果,识别出中、重度超标程度的农用地在未来的利用变化情况,对比基于安全利用标准的地类转换方向,判断利用方向的合理性。研究得到的主要成果有:(1)通过对研究区土地利用变化特征的分析,当地经济发展速度较快,乡镇企业发达,建设用地扩张幅度较大,园地和林地面积明显减少。由于土地开发整理或村庄整治等原因被整理成可耕作状态,其他用地面积显著减少,水田和旱地水浇地面积明显增加。(2)通过分析研究区农用地重金属超标现状评价结果,发现A镇中、重度超标程度农用地的面积占总面积的0.4%,主要分布在中部建成区附近。对中、重度超标农用地进行地类调整,转换方向均为园地或林地。即在同一pH值下,水田、旱地和水浇地对重金属浓度的容纳限值没有明显差异,不会发生互相转化的情形,而转为标准值较高的园地和林地之后,农用地的重金属相对超标程度均降低,初步实现了标准意义上的安全利用。(3)基于模型预测结果和安全利用评价结果,分析了2013~2021年研究区重金属超标农用地变化情况,发现绝大部分水田、旱地水浇地保持原来利用方式,其他转向建设用地和其他用地。通过与基于标准的地类转换类型进行对比分析,分别从安全利用角度和实际利用情况分析转换方向的合理性,并根据转变类型提出可供参考的管控建议。通过本文对重金属超标农用地安全利用的调控研究,可以在实践上为乡镇尺度重金属污染区域农用地安全利用的方向提供视角和方案依据。
[Abstract]:At present, heavy metal pollution in soil affects the quantity and quality of agricultural land and the safety of agricultural products in villages and towns, and may threaten people's health. Therefore, the study on the safe utilization of heavy metals in the town area can provide a good reference for the rational utilization and protection of agricultural land on the township scale. Firstly, based on CLUE-S model, the spatial distribution of land use in town A is predicted. Based on the integrated evaluation criteria for the safety utilization of heavy metals over standard agricultural land, this paper evaluates the situation of heavy metals exceeding the standard in town A, and determines the safe utilization direction of agricultural land of moderate and severe degree of exceeding the standard by the method of land class conversion. Based on the results of safety utilization evaluation and model prediction, the changes of land use in the future with moderate or severe degree exceeding the standard are identified, and the rationality of the utilization direction is judged by comparing the transformation direction of land types based on the safety utilization standard. The main results of the study are as follows: (1) through the analysis of the characteristics of land use change in the study area, the local economy develops rapidly, the township enterprises develop, the construction land expands greatly, and the area of garden land and forest land decreases obviously. As a result of land development and consolidation or village renovation, other land areas were significantly reduced, and the area of paddy fields and dryland irrigated land increased significantly. (2) by analyzing the present situation of heavy metals in agricultural land in the study area, the results were evaluated. It is found that in town A, the area of heavy agricultural land exceeding the standard level accounts for 0.4% of the total area, which is mainly distributed near the central built-up area. The land types of medium and severe agricultural land were adjusted and the conversion direction was garden land or forest land. That is, under the same pH value, the tolerance limit of heavy metal concentration in paddy field, dry land and irrigated land has no obvious difference, and it will not transform to each other, but to garden land and forest land with higher standard value. The relative excess degree of heavy metals in agricultural land was reduced, and the safety utilization of agricultural land was preliminarily realized in the standard sense. (3) based on the results of model prediction and safety utilization evaluation, the variation of heavy metals in the study area from 2013 to 2021 was analyzed. It was found that most paddy fields, dry land irrigated land remained the original utilization mode, others turned to construction land and other land use. The rationality of conversion direction is analyzed from the point of view of safety utilization and actual utilization, and some suggestions for control and control are put forward according to the change type. Through the study on the regulation and control of heavy metal safety utilization in agricultural land, we can provide the visual angle and plan basis for the direction of agricultural land safety utilization in the township scale heavy metal pollution area in practice.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53

【相似文献】