陕西省‘冬枣’气候优生区区划研究

Study on the regionalization of optimum areas for‘Dongzao’growing in Shaanxi province

【目的】进一步掌握陕西省优质‘冬枣’气候优生区的地域分布特征。【方法】采用1981—2018年全省98个国家气象站的日数据资料,结合‘冬枣’生物学特性,选取影响全省‘冬枣’生长发育的关键气候因子作为全省‘冬枣’气候优生区区划因子,采用模糊数学方法建立隶属函数,用层次分析法确定权重,三维二次趋势面法分区建立各区划因子模型,利用GIS绘制优生区区划因子的单因子细网格图层,最后通过模糊综合评价法得出全省‘冬枣’气候优生区区划图,按照优生区、适宜区、次适宜区、不适宜区将全省分为四个区。【结果】‘冬枣’种植的气候优生区和适宜区主要分布在关中中东部大部分地区的平原地带,陕北黄河沿线各县海拔低于900 m的浅山地带,呈径向分布;‘冬枣’种植的气候不适宜区主要分布在陕北的西部各县、陕南秦巴山区及秦岭山脉沿线海拔较高地区。【结论】陕西省‘冬枣’优生区和适宜种植区主要位于渭南市、阎良区、临潼区,长安区、鄠邑区、三原、泾阳、蓝田、周至的北部,府谷、神木、佳县、米脂、绥德、吴堡、清涧等低海拔地区,该区域地势平坦,土地肥沃,气候资源配置优势明显,适宜规模种植,建议在此区优先发展‘冬枣’种植产业。另外,影响此区‘冬枣’生长的主要气象灾害是果实成熟期的连阴雨及秋淋,应重点防御。

【Objective】The study aims at clarifying the geographical distribution characteristics of the high-quality‘Dongzao’growing zones in Shaanxi province.【Methods】Based on the daily data with 98 national meteorological stations in the whole province from 1981 to 2018,the biological characteristics of‘Dongzao’were combined with eight key comprehensive climatic factors including negative accumulated temperature,annual maximum temperature,frost-free period,average temperature from March to May,sunshine hours from June to August,precipitation in September,sunshine hours in September,accumulated temperature during the whole growth period,which may influence the growth and development of‘Dongzao’in the whole province,so that they served as the optimum zoning index.The membership function of each region index was established by fuzzy mathematics method and the weight was determined by analytic hierarchy process.In addition,three-dimensional quadratic trend surface method was used to set up the index model for each region(northern Shaanxi,southern Shaanxi and central Shaanxi)and GIS method was used to draw the single-factor sub-grid layer of the whole province’s‘Dongzao’zoning index.Finally,the whole province was divided into four zones including optimum zone,suitable zone sub-suitable zone and unsuitable zone.The optimum climatic zoning map for‘Dongzao’was obtained by fuzzy comprehensive evaluation.【Results】The optimum zone and e suitable zone were distributed along the Yellow River in Northern Shaanxi and the middle and eastern parts of Guanzhong area.The annual average temperature in the optimum zone for‘Dongzao’growing was 10-14℃,the average temperature from the blooming to the young fruit set stage was 12-15℃,the frost-free period was 200-220 d and the annual precipitation was 400-600 mm.It was the optimum zone that developed‘Dongzao’industry in Shaanxi province with the aid of well matched water and heat resources,the gentle terrain,fertile soil and good site conditions.Secondly,some parts in the eastern part of the county along the Yellow River in northern Shaanxi and some parts in southern Shaanxi,the Yellow River coastal areas and the low hill areas with an elevation less than 800 m were also the optimum zone for‘Dongzao’growing.The suitable zone for‘Dongzao’growing was mainly distributed in the shallow mountain belt with an elevation less than 900 m along the Yellow River counties including west part of Fugu county,Shenmu county,Yulin city,Jiaxian county,Mizhi county,Wubao county,Suide county,Zizhou county,Qingjian county,Yanchuan county,Yanchang county,Hengshan county,etc.in northern Shaanxi.In these areas,the average temperature was 9-10℃,the average temperature from bud break to blooming was 11-13℃,the frost-free period was 170-190 d,and the annual precipitation was between 400-440 mm,the fertile soil and the well matched climate resources were very suitable for‘Dongzao’growing.The unsuitable areas for‘Dongzao’growing were mainly distributed in the western part of northern Shaanxi,the higher elevation areas along the Qinling Mountains as well as the mountainous areas,and the woodland and gully areas.In these areas,the terrain was complex,the altitude was high and the slope was abrupt,which was not suitable for‘Dongzao’growing.【Conclusion】The optimum and suitable areas for‘Dongzao’growing in Shaanxi province were mainly located in the low-altitude areas like Weinan city,Yanliang district,Lintong district,the north of Chang’an district,Huxian county,Sanyuan county,Jingyang county,Lantian county,the north of Zhouzhi county,Fugu county,Shenmu county,Jiaxian county,Mizhi county,Suide county,Wubao county and Qingjian county,the optimum zones had flat terrain,fertile soil and obvious advantages in climate resource allocation,which was suitable for large-scale planting.It was suggested to give priority to the development of‘Dongzao’growing industry in these areas.In addition,the main meteorological disasters that affected the growth of‘Dongzao’in this area included the continuous overcast rains and autumn shower during the fruit ripening period,which should give more concern.From the meteorological point of view,combed with the altitude,the climatic optimum zone for‘Dongzao’growing was obtained and it was also a prerequisite for trees to live and grow into forests with high quality and stable yield.Due to the lack of the introduction and cultivation efficacy by soil fertility factors and land usage status,the physiological and biochemical indexes of trees as well as soil and social factors should be combined to further enrich the results of the climatic optimum zones for‘Dongzao’growing,so as to make it more valuable for guiding introduction and cultivation in the future.