Abstract: The purpose of this study is to clarify the fine distribution of climatic suitable area for apple planting in the northern extension area of Shaanxi province in the new climate period (1991−2020), and reveal the development potential of apple planting in this region. Based on the meteorological observation data, the digital elevation model data and the arable land confirmation data，the requirements for the climatic suitability and mountainous site conditions of apple planting in the northern expansion area of Shaanxi province were comprehensively analyzed. Seven factors, including annual average temperature, annual precipitation, average relative humidity from June to August, average minimum temperature from June to August, average temperature in January, aspect and slope, were selected as zoning indexes to divide the climatic suitability of apple planting in the research area. The multiple regression method was used to simulate and calculate the spatialization of every climatic factor. Then the suitability quantitative evaluation model of each single factor was constructed by fuzzy set linear membership function method. The climatic suitability regionalization of apple planting in the northern extension area of Shaanxi was developed by weighted comprehensive evaluation and set optimization methods. Finally, the distribution of dry land and irrigation area in the suitable planting area for apple of each district was extracted by using the arable land confirmation data. The results showed：(1) the northern boundary of the suitable area for apple planting in Shaanxi was from Wuqi county, the middle and south of Jingbian county to the northeast through the south of Hengshan county, Mizhi county to the middle and southern of Jiaxian county, whose terrain were mainly hilly and gully area along the sunny gentle slope, with a general altitude of 730-1660m. (2) The field investigation showed that the zoning result was about 80% consistent with the field planting distribution of apple orchard. (3) The refined spatial distribution of climatic appropriate areas for apple by county (district) based on the arable land confirmation data showed that the area of climatic suitable level above for apple could be developed in the northern expansion zone was about 276.9kha, accounting for 24.6% of the available arable land, among which the dry land area accounted for 96.3%, with rain-fed agriculture as mainstay. Compared with the statistical data of apple planting status in each county (district), it could be seen that there was still 4.9−28.5kha development space in most counties (districts) except Shenmu county and Fugu county in Yulin city, and Wuqi county in Yan’an city. The potential planting area of climatic suitable for apple in Zhidan county in Yan’an city had tended to be saturated. The results can provide reference for optimizing regional layout of apple industry under the background of climate change.

Key words: Apple, Climate, Suitability model, Planting development potential