Variations trend of climate parameters affecting on grape growth (Case study: Khorasan Razavi Province)

The present study aims to investigate the structure and trend of climate parameters affecting grape growth in Khorasan Razavi (north eastern Iran) in the period of 1991-2015 in 8 weather stations. Effective climate elements such as temperature, precipitation, the number of hot days, the number of frost days, sunshine hours and parameters such as maximum temperature, annualaverageannual average of temperature and precipitation, the growing season and phenological stages were calculated, and their effects on the quality of grapes were assessed. In general, Thethe results indicatedd that in general, the warming in the growing season with a significant increase in great accumulation indices, particularly the increase in the maximum temperature, mean temperature, the number of days with maximum temperature bigger than 90th percentile, and the number of days with the maximum temperature greater than 30 °C. Precipitation during the growth period particularly in the germination and blooming for all stations is reduced. This issue indicates potential soil moisture stress during this vital growth stage. Analyzing the crop evapotranspiration (ETC) indicated that because of warming, demands for water in the region have increased from 10% to 20% percent. These observations along with the continuation of global warming indicate that grape growth with favorable quality is impossible without adopting adaptations to the future climate changes.