| Apples are one of the most widely cultivated fruits in the world.China is the country with the largest apple production in the world,and the Loess Plateau is the largest apple producing area in China.However,due to differences in soil,climate and geographic conditions,apples from different regions of the Loess Plateau differ greatly in quality,taste and nutritional composition,resulting in large differences in their market prices and economic benefits.In order to promote the sustainable development of the apple industry in the Loess Plateau region with high quality and efficiency,and to actively respond to future climate change,this paper takes the Loess Plateau region as the research object,uses TOPSIS model to score the intrinsic quality of apples in the study area,obtains the geographic distribution point data of high-quality apples,and applies Arc GIS spatial analysis method combined with MaxEnt model to Based on the model performance evaluation and parameter optimization,the importance of different environmental variables on the distribution of high-quality apples was evaluated by replacing the importance value,contribution rate,Jackknife test and other parameters,and based on the single-factor response curves of environmental variables,the main environmental variables of suitable distribution of high-quality apples were obtained.The threshold ranges were used to predict the distribution of potential suitable areas for high-quality apples and their migration trends in the Loess Plateau region under current and future climatic conditions(SSP1-2.6,SSP2-4.5,SSP5-8.5),respectively.The results of the study were:The AUC value of the MaxEnt model is greater than 0.9,and the prediction results for the potential suitable distribution area of high-quality apples are relatively high.The climatic factors that have the greatest impact on the distribution of high-quality apple suitable areas are precipitation seasonality,monthly average temperature difference and the hottest monthly high temperature,soil factors is carbonate or lime content,available potassium and available phosphorus content,and topographic factor is slope aspect.The suitability of high-quality apples is gradually decreasing from south to north in the study area,and the highly suitable areas are mainly distributed in the eastern part of Pingliang in Gansu,the southern part of Yan’an,Xianyang,Tongchuan,northern Weinan,central and eastern Baoji in Shaanxi,the southern part of western Yuncheng in Shanxi,Sanmenxia and western Luoyang in Henan,and the suitable areas are mainly distributed in Qingyang and Tianshui in Gansu,the northeastern part of Yan’an City in Shaanxi,and the central part of Linfen and central Jincheng in Shanxi.The suitable areas are mainly located in Gansu Qingyang,Tianshui,northeastern Yan’an City in Shaanxi Province and central Linfen,central Jincheng,western Yinchuan in Ningxia Province.Under the future climate conditions,the increase of suitable areas in the future 2050 s compared with the current period is 0.62 million km2,18.1 million km2 and 14.6 million km2 in the SSP1-2.6,SSP2-4.5 and SSP5-8.5 climate models,respectively,and the overall change of the distribution pattern of suitable areas is not significant.(3)Under the future climate scenario,the center of mass of suitable areas will move southward in 2050 s,with the minimum distance of 9.48 km and the maximum distance of23.78 km under different climate models;the maximum linear distance of the center of mass of suitable areas will move 40.89 km and the minimum distance will be 2.50 km in 2070 s,which is consistent with the seasonal trend of precipitation in Loess Plateau region.The conclusion is that the distribution of potential suitable areas for high-quality apples in the Loess Plateau is mainly affected by seasonality of precipitation,monthly mean temperature difference,high temperature of the hottest month,soil carbonate content,available potassium,available phosphorus and slope aspect.In the current period,the high suitability areas are mainly distributed in the south-east of the Loess Plateau,and the suitability gradually decreases from south to north.In the future,the area of suitable areas will increase,among which the area of high suitable areas will increase the most,and its center point will migrate to the northwest.The newly added and lost areas of suitable areas will occur in the central part of the Loess Plateau. |
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