关键词: 晚熟柑橘, 最大熵模型, 地理信息系统, 适宜性评价

Abstract:

【Objective】Carrying out the suitability evaluation of late-maturing citrus in Dongpo District, Meishan City, can provide scientific references for the reasonable cultivation and optimization of production space of local late-maturing citrus. 【Method】Based on 14 climatic indicators, 3 topographic indicators and 22 soil physicochemical indicators, as well as data from 372 sampling points of late-maturing citrus planting areas, the article utilizes the Maximum Entropy Model (MaxEnt) and Geographic Information System (GIS) in combination with correlation analysis to screen key environmental factors affecting the distribution of late-maturing citrus in Dongpo District, Meishan City, Sichuan Province, and constructs a model for evaluating the suitability of late-maturing citrus planting. The model was constructed to evaluate the suitability of late-maturing citrus planting.【Result】The MaxEnt model was very effective, and the area under the curve (AUC) in the characteristic working curve (ROC curve) of the subjects reached 0.843, which was highly accurate and reliable. The MaxEnt analysis showed that the average annual air temperature, elevation, total phosphorus, pH, average annual relative humidity, pulverization, annual precipitation, annual sunshine hours, autumn precipitation, soil exchangeable calcium, total potassium and organic matter were the main environmental factors affecting the distribution of late-maturing citrus; the cumulative contribution of climatic variables affecting the distribution of citrus was 43.0%, of which mean annual temperature (22.9%), mean annual relative humidity (7.0%) and annual precipitation (4.6%) were the three most important climatic factors affecting the distribution of late-maturing citrus; the cumulative contribution of soil variables affecting the distribution of late-maturing citrus was 41.3%, of which total phosphorus (13.8%), pH (10.4%) and chalkiness (5.7%) were the three most important soil factors affecting the distribution of late-maturing citrus; elevation was a topographic factor affecting the distribution of citrus, with a contribution rate of 15.7%. By statistically analyzing the parameter values of each dominant environmental factor in different levels of distribution areas, combining the response curves of each ecological factor, the field survey and the review of the literature, a comprehensive analysis was made to conclude that the basic climatic and topographical environmental requirements for the distribution of late-maturing citrus are as follows: the average annual air temperature is about 17 ℃, the average annual relative humidity is 80%, the annual rainfall is about 1 300 mm, the annual sunshine hours are 1 350 h, and the rainfall in autumn is about 390 mm, altitude of about 400-700 m; soil pH of 4.5-7.5, while the soil nutrient status is affected by the combination of standing conditions and cultivation and management measures. Of the 34 673.29 hm² of gardenable land in the region, 23.51%, 61.37% and 15.12% were in the dominant, suitable and unsuitable zones, respectively.【Conclusion】This study objectively reflects the changing characteristics of late-maturing citrus planting suitability, suitable area and distribution in Dongpo District under the influence of climate, topography and soil factors.

Key words: late maturing citrus, maximum entropy model, geographic information system, suitability evaluation