Zoning Of Frost And Disease During Apple Flowering Period In Shaanxi Province And Research On Key Issues In The Development Of Apple Industry In Yulin Mountain Area

As a pillar industry that enriches people of Shaanxi Province,apple industry in Shaanxi province accounts for over 1/4 of the national apple production.The natural conditions in the mountainous areas of northern Shaanxi benefits the quality of apple.Known as"mountain apple",it is the symbol of high-quality apples in Shaanxi Province.The terrain and geomorphology of the province are complicated,especially for apple producing areas.The complicated climate conditions have an important impact on the stability of apple production and the occurrence of apple diseases.Therefore,understanding the production status of mountain apple producing areas,accurate analysis of apple flowering frosts and major disease risk zoning from the perspective of spatial distribution,and the research on mountain apples flowering phenology period control,have positive practical significance on optimizing the industrial layout of agricultural production,disaster prevention and mitigation.In this study,we investigated different scale operating entities,government departments and technical experts in the main production areas of mountain apple.Additionally,the production status of mountain apple was analyzed.Based on the meteorological data of 41weather stations for the apples flowering period from 1990 to 2019,combined with the occurrence data of two major apple diseases(rotten disease and early deciduous disease)from 2017 to 2021 in 41 major apple regions in the province with Arc GIS support,the risk of frost and main apple diseases in Shaanxi province were regionalized respectively.Finally,the flowering regulation of frost in mountain apple was investigated.The main conclusions are as follows:1.The scale of mountain apple industry develops rapidly,but the production technology is relatively weak.The technical team of fruit industry is poorly organized.Management ability of orchard owners and the professional quality of fruit industry labors are relatively inadequate,resulting in the overall low profit of the orchard.The main production organization mode in mountain apple region is the mode with large production households and cooperatives.The large area of single household production is conducive to the establishment of socialized service system of apple industry.By linking the agricultural socialized services,we can break the barrier of non-sharing means of production among small farmers,so that each orchard can benefit from the dividends brought by large-scale production.2.The kriging interpolation method was used to spatially interpolate the point data set of meteorological elements.The frost risk of apple flowering period in the whole province was divided into 4 categories by the best natural fracture method.Thus,the comprehensive frost risk zoning map of apple flowering period was obtained.According to the degree of occurrence risk,it is classified as follows:Category I heavy occurrence risk area;Category II moderate occurrence risk area;Category III light occurrence risk area;and Category IV general occurrence risk area.Among them,category I is mainly distributed in the west of Yan’an city in northern Shaanxi province and the west and north of Yulin City,involving 8 counties and districts with area of 15,154.69.39 km~2.Class II moderate risk area,mainly distributed in the west of Yan’an and the west and north of Yulin with a total of 15 counties covering an area of 30633.69 km~2;Class III light occurrence risk area,mainly distributed in the majority of Yan’an city and the southern part of Yulin City,involving yulin City,Yan’an City,Baoji City,Xianyang city,a total of 22 counties and districts,covering an area of 27525.25 km~2;Categoryⅳgeneral risk area,mainly distributed in the southern Baoji City,Xianyang City,Xi’an city,Weinan city and other major areas and small areas of Yan’an,6 cities,a total of 77counties and districts,covering an area of 62093.19 km~2.The main areas of mountain apple are Baota district and Yanchang County in the north of Yan’an city and Mizhi County and Suide County in the south of Yulin City,which belong to class III light occurrence risk areas.It is an effective measure to regulate and delay the flowering stage of apple to deal with the risk of frosting in apple flowering stage.According to the observation of the experimental results of regulating and controlling the flowering stage of apple in mountain,multiple measures are effective such as irrigation in spring,grass covering on tree trays,and potassium naphthylacetate spraying,and the best scheme is the shading treatment of apple orchard in spring.3.The same method was used to divide the risk zones of main apple rot and early leaf deciduous disease in Shaanxi Province.The risk zones of apple diseases in Shaanxi Province was divided into 4 categories by the best natural fracture method.According to the degree of occurrence risk,the disease risk zones are classified as follows:Category I heavy occurrence risk area;Category II moderate occurrence risk area;Category III light occurrence risk area;Category IV general occurrence risk area.The regionalization results showed that the proportions of class I heavy risk area,Class II moderate risk area,Class III light risk area and class IV general risk area were as follows:4.94%,26.78%,26.91%,41.38%.From the perspective of the whole province,the occurrence risk of apple tree canker was low,with the probability of severe tree canker being less than 5%,and the proportion of light tree canker and general risk areas was 68.29%.The proportions of the four risk areas of early leaf litter disease were as follows:11.57%,28.10%,32.74%,27.59%.From the whole province,apple early deciduous disease risk is low,and the scope of occurrence is relatively concentrated,light and general risk areas accounted for more than 60%,mountain apple development area early deciduous disease is light and general risk areas.The proportions of the four types of risk areas for the comprehensive occurrence of the two diseases are 14.20%,26.31%,31.86%and 27.63%,respectively.From the perspective of the province,the risk degree of the comprehensive occurrence of the two main diseases is moderate,light and general,and the risk of severe occurrence is relatively low and the occurrence scope is relatively concentrated.The comprehensive risk of apple disease in the developing area of mountain apple was mainly light and common.Through the comprehensive investigation of production areas,the analysis of climate and disease information data,and the study of some specific countermeasures,this study explored the modern development mode of mountain apple industry.We produced the risk zoning of apple freezing injury and apple disease disaster risk zoning in the whole province.This can be applied in planning high-quality orchards with stable output of apples,early warning and prevention,control of apple diseases as well as ensuring the healthy and green production of characteristic apple industry in Shaanxi Province.