Delimitation of permanent basic farmland in mountain and hill areas in southwest China based on multiple-objective decision model

Abstract: In order to guide the delimiting permanent basic farmland in the mountain and hill areas, this paper sets up a multiple-objective decision model by using Chongqing Dianjiang as an example. The model is supported by data analysis using ArcGIS 10.1 and other software based on the 2012 Second Land Survey data and Land Use Overall Planning data of 25 towns, basic farmland planning data, soil data, and investigation of county and country Land and Resource departments using spatial distribution products of more than 10℃ accumulated temperature in the cloud platforms of Geography National Condition monitoring. The model is also supported by the AHP (Analytic Hierarchy Process), Entropy Coefficient Method, TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution), and constraint fact. First, the subjective weight of each index is given based on the AHP method by analyzing and erecting the judgment matrix. The objective weight is obtained by using the Entropy Coefficient Method by building the judgment matrix to a normalized process. The value of measurement and closeness of positive and negative ideal points is reflected through erecting Euclidean distance in the normalized matrix. The higher was the value of measurement and closeness, the higher was the priority of land. The call-out qualifications of farmland are confirmed by the constraint fact method in 4 investigations, which supplies the conditions of the Construction land or general farmland. The paper concludes that in the standardized normal outcome of the farmland decision index, the optimum conditions are farmland irrigation, rainfall, transportation, and rural residential radiation. For most soil quality indexes, the range of equal value, STD, and CV are 0.2, 0.6, 0.1, 0.3, and 13, 75. Overall, the value of CV is below medium while existing comparable large areas have a high value or a low value. Variation in subjective and objective weights of these indexes, after normalization, causes the maximum weight to be farmland irrigation and farmland connectivity. The minimum weight is more than 10℃ accumulated temperature, average rainfall in natural conditions, organic carbon in soil quality by analytic hierarchy process, transportation, rural residential radiation, and towns radiation in distance condition. The most important conditions for selecting permanent farmland are farmland irrigation > farmland connectivity > towns radiation > soil organic carbon. According to the value of measurement and closeness of positive and negative ideal points, the quality of farmland is generally close to each other, and the distance condition is at it's best and comparatively stable. Therefore, whole performance is better. Four grades are divided as key, proper, adjusting, and reserved, in which farmland is chosen as permanent basic farmlands using the natural breaks method to reclassify the closeness degree. There are special differences among different grades in statistics and spatial patterns. Local departments prefer to select superior farmlands, which are in the "key" and "proper" grades, in the selection under constraint conditions. In the ultimately delimited results, the proportion of proper and adjusting grades increases, while the proportion of key and reserved grades decreases. The rationality, standardization, and practicability of the model are verified by comparison among ultimately delimited results, high weight index in the model, and a basic farmland protecting area plan. The multiple-objective decision method is not only suitable for delimitation of permanent basic farmland in the mountain and hill areas in southwest China, but also ensures red line and economic growth, which supplies the theoretical basis and the decision reference for the study of complementary delimitation in the mountain and hill areas.