Ecological Suitability Evaluation Of Flue-cured Tobacco In Southern Shaanxi Province

Flue-cured tobacco area in the mountains and hills of southern Shaanxi Province is the main tobacco growing area of Shaanxi province,with the planting area accounting for 80% of the province’s tobacco planting area and the annual tobacco output accounting for more than80% of the province.Flue-cured tobacco production is one of the important sources of local farmers’ income.Therefore,ecological suitability evaluation and fine partitioning of fluecured tobacco planting in southern Shaanxi can be conducted to plan and guide flue-cured tobacco planting and production according to local conditions.It is of great significance to improve the yield and quality of tobacco,enhance the core competitiveness of Shaanxi tobacco,increase the income of tobacco farmers and develop local economy.In this study,meteorological data,soil data,topographic data,57 flue-cured tobacco distribution samples and 19 biological environmental variables were used in the growth period of southern Shaanxi from 2010 to 2019.Fuzzy comprehensive evaluation and Max Ent model were used to evaluate the single factor suitability of climate,soil,terrain and other factors and comprehensive suitability of flue-cured tobacco planting in southern Shaanxi.By comparing the results of the two methods and combining with the current planting situation of flue-cured tobacco in southern Shaanxi province,it is concluded that the Max Ent model has a higher zoning accuracy,which provides a scientific basis for the optimization of flue-cured tobacco planting layout in the study area.The main research conclusions are as follows:(1)Most areas in southern Shaanxi could meet the temperature requirements of fluecured tobacco in different growth stages.Hanzhong,Ankang and Shangluo producing areas all have decreased suitability due to excessive rainfall in maturity period,especially Hanzhong and Ankang tobacco-producing areas with greater risk,which restricts the quality of flue-cured tobacco production.(2)According to the suitable distribution of flue-cured tobacco sample points in the results of different methods,the accuracy of different methods was verified in the suitable partition of three single factors: climate,soil and terrain.The results showed that the Max Ent model predicted the number of sample points above the appropriate area was more than that of the fuzzy comprehensive evaluation,indicating that the Max Ent model had a higher zoning accuracy for flue-cured tobacco planting in southern Shaanxi.(3)Five methods,namely traditional ecological index model prediction,total ecological index model prediction,fuzzy comprehensive evaluation weighting,traditional ecological index weighting and total ecological index weighting,were used to carry out ecological comprehensive evaluation.Through the verification of the appropriate distribution of fluecured tobacco sample points,all 57 sample points in the zoning results of the traditional ecological index model weighted method were above the appropriate area,with the highest zoning accuracy.(4)In the traditional ecological index model weighted comprehensive zoning results,the area above the appropriate area is the largest,and the area below the sub-appropriate area is the smallest.Among them,the most suitable area accounts for 11.08%,which is mainly distributed in the central and southern part of Hanzhong City,and several counties and districts south of the central part of Ankang City have a small area distribution,including Luonan and Shangzhou in Shangluo City.The suitable area accounts for 77.55%,which is large and widely distributed in all counties,mainly distributed in the central,southern and western parts of southern Shaanxi.The sub-suitable area accounted for 11.37%,mainly distributed in Liuba of Hanzhong City and a few areas of adjacent counties,Zhashui,Zhen ’an,Shangnan and Luonan counties of Shangluo,and a few in Ningshan and Hanbin of Ankang;There is no suitable area.