An agrometeorological study of crop production in Khorasan

Agriculture is highly sensitive to climate variability and weather extremes and weather fluctuations play a significant role on crop growth and yield. Impacts of climate variability is more prominent in arid and semi-arid conditions. Iran is located within arid and semi-arid belt and shows a highly variable climate. A through agrometeorological study was carried out to investigate the relationship between various crops (wheat, barley and chickpea, sugarbeet, cotton, alfalfa,) and fruits (melon and watermelon) production and climate indices including number of hot days (Tmax>30ºc), number of wet days (P > 0 mm) and consecutive dry days (CDD) for Khorasan province in northeast of Iran. All associations were assessed during growing season and under both rainfed and irrigated conditions since 1984-2005. Daily weather data (1984-2005) were collected from the available database of Khorassan Climatology Center. We found a significant negative correlation between the CDD, number of hot days and study crops yield, however significant positive correlations have been obtained between the number of wet days and yield mostly under rainfed condition but not across all locations. Maximum correlation coefficient (r) for CDD, number of hot days, number of wet days and yield were -0.59 for rainfed pea at Mashhad, -0.57 and 0.62 for rainfed barley at Torbat heydarieh respectively.