Evaluating the Ability of Grapevine Cultivation in Iran Based on Climatic Conditions

In order to choose the best forms for each region and invest, the climatic conditions should be considered. Among the climatic elements, thermal indexes are effective factors in the production cycle, and the quality and quantity of grapes. Given the lack of water resources and the threat of climate change, there is a need for potentiometry and clustering of different regions.

According to the content and purpose of statistics and information, the hourly and daily climatic data of 200 climate stations were used. In order to compute the required chilling, the CH model was prepared and implemented. According to daily and monthly statistics, climate parameters were refined and investigated. We used a weighting method based on hierarchical approach for accurate decision making and identifying the relative importance of climatic criteria for grape cultivation. For the following climatic criteria, the information layer was arranged through a database of 200 meteorological stations of the Iranian Meteorological Organization. For the following geographic criteria, layers were used in the country. In order to determine the suitable areas for planting grapevine, using the Analytical Hierarchy Process (AHP) method in the Epert choice11 software environment, the criteria and sub criteria were weighted. Then, using the Geographical Information System, the layers were overlapped based on their weight and the final land suitability map for planting grapevine in Iran was obtained based on climatic conditions.

Pairwise comparison of criteria and sub-criteria based on hierarchical analysis showed that the criterion of climatic conditions with a weight of 0.63 was considered as the most important criterion in determining suitable areas for grapevine cultivation. Pairwise comparison of the climatic conditions criterion indicated that the sub-criteria of 451 were the highest among the sub-criteria in the grape trees. Temperature sub-criteria exhibited the greatest weight during the slump and growth period. Paired comparison and spatial distribution of the climate-chilling showed that a large part of the country does not supply winter creeps or cold storage for grapevine trees. The southern half of Iran is entirely unsuitable due to the existence of mild winters for commercial cultivation of creeping trees such as grapes. Paired comparison and spatial distribution under the climatic criterion of the slump period demonstrated that largest spatial distribution is allocated to the middle class in the margin of highlands and high latitudes regions. Paired comparison and spatial distributions under the scale of the growth period illustrated that the spatial pattern in this sub-criteria is highly dependent on the altitude and latitude. From the north to the south and from the west to the east, the suitability for growing grapevine decreases. Paired comparison and spatial distributions under the climatic criteria of absolute minimum temperature revealed that in terms of absolute minimum temperature, there is a limitation on grapevine for some regions of Iran. These areas are mainly mountainous belts of the Zagros mountain, the northwest cold region and northeastern Iran. Paired comparison and spatial distribution under the climate criteria of maximum air temperature showed that temperatures above the threshold of 40 degrees Celsius adversely influence the quality and yield of grapevine. In fact, in terms of absolute maximum temperatures, more than half of the country's surface area is unsuitable. Paired comparison and spatial distributions under the geographic scale elevation above sea level showed that suitable altitude areas are limited to the high and mountainous regions of the northwestern, northern, and northeastern Iran. Paired comparison and spatial distributions under the relative climate of relative humidity indicated that due to the relative humidity of the grape vine compared to many fruit trees, the relative humidity in Iran is high for the grapevine tree. Paired comparison and spatial distributions under the climatic criteria of sunshine hours illustrated that the distribution of sunshine hours affects the latitude factor causing an increase in sunshine hours from north to south. A wide range of  growing fruit trees in terms of sunshine days can be found in Iran. Therefore, most regions in the country provide unlimited solar radiation for grapevine growth. Paired comparison and spatial distributions under the geographic scale elevation above sea level showed that altitude plays an important role for locating vineyards. Suitable high-altitude areas are limited to the high and mountainous regions of the northwestern, northern, and northeastern Iran. Paired comparison and spatial distribution below the gradient geographic scale showed that planting fruit trees, especially grapes, is more cost-effective in steep slopes. Considering the high adaptability and physiological conditions of the grapevine, almost all regions of Iran, except very high and mountainous regions, are suitable for planting grapes. Suitable vineyard cultivars are adapted to the slopes of mountainous and relatively high mountainous regions in the mid-west, northwest, northeast, and scattered areas of the center, east and south east of the country. The range of cultivating grapevine trees is 42% of the country's surface area.   

The results revealed that the climate criterion has a pivotal role for determining land suitability for grapevine trees. The suitable vineyard cultivars are located in the mountainous and relatively hilly mountains in the northwest, northwest, northeast, and dispersed areas of the center, east and south east of Iran. These findings are important for land use planning and spatial planning with emphasis on climatic and geographic capabilities for efficient use of natural resources.