耕层土壤剥离再利用覆土时空优化研究

Study on Spatio-Temporal Optimization of Plow Layer Soil-Stripping and Reusing of Cultivated Land

科学确定有覆土需求的地块,是耕层土壤剥离与再利用工程的先决条件.本文在ArcGIS技术支持下,以重庆市江津区为例,采用信息熵法构建了规划期内山地丘陵区耕地耕作层覆土需求优先度的评价指标体系,根据覆土优先度综合分值划定近期覆土区、中期覆土区、远期覆土区.结果表明:1)基期(2013年)至规划期(2020年),非农建设用地转化为耕地的现象覆盖了研究区大部分区域,覆土区总面积为648.27hm^2;2)基于自然条件、社会条件和用地条件,采用熵权法对上述指标进行权重计算,得出2013-2020年江津区覆土优先度综合分值Q,Q≥0.49的覆土区域划为近期覆土区,0.35≤Q<0.49的覆土区域划为中期覆土区,Q<0.35的覆土区域则划为远期覆土区;3)近期覆土区覆土迫切性较高,具有较强的社会可行性,应优先安排耕层土壤覆土工程;中期覆土区优先度次于近期覆土区,为后备覆土区域;远期覆土区缺乏一定的经济基础,总体来说该区域覆土迫切度较低,覆土社会可行性不高.因此,覆土改良不仅要考虑土壤质量等自然条件,还应考虑社会条件和用地条件,而确定合理的覆土时序和覆土区域则关系着耕层土壤剥离与再利用工程的投资、工期和效果.

Finding out the parcels having the demand of soil-covering scientifically is the prerequisite of a project of soil-covering of plow layer soil-stripping and reusing of cultivated land.Based on geographic information system（GIS）technology,this paper took Jiangjin district of Chongqing city as the study area,and utilized the method of information entropy to establish the evaluation index system of the priority of soil-covering demand of plow layer of cultivated land in in hilly-mountainous areas in the planning period,and then determined the near-term soil-covering regions,the mid-term soil-covering regions and the longterm soil-covering regions according to the priority score of soil-covering demand.The results were as follows.Firstly,the phenomenon of non-agricultural construction land converted into cultivated land covered most of the study area,and the area of the soil-covering regions totaled 648.27 ha from the base period（2013）to the planning period（2020）.Secondly,based on the natural conditions,social conditions and land conditions,the entropy weight method was used to calculate the weights of the above indexes,to calculate the priority score（Q）of soil-covering demand in Jiangjin district from 2013 to 2020.When Q≥0.49,the soil-covering regions were classified as the near-term soil-covering regions.When 0.35≤Q〈0.49,the soilcovering regions were classified as the mid-term soil-covering regions.When Q〈0.35,the soil-covering regions were classified as the long-term soil-covering regions.Thirdly,in the near-term soil-covering regions the project of soil-covering of plow layer should be carried out,because they have the strongest urgency of soil-covering and a strong social feasibility.The priority of mid-term soil-covering regions was just lower than that of near-term soil-covering,and we regarded the mid-term soil-covering regions as alternative soil-covering regions.Long-term soil-covering regions lacked a certain economic basis,and had a low priority of soil-covering and a low social feasibility as a whole.Therefore,when carrying on the work of soil-covering and improvement,we should consider not only soil quality and other natural conditions,but also the social conditions and land use conditions.Meanwhile,determining the soil-covering sequence and regions reasonably will affect the investment,construction periods and operation effects of the project of soil-covering of plow layer soil-stripping and reusing of cultivated land.