Evaluating overlap of Abhar region growing period with growth cycle of rainfed winter wheat and spring barley

Growing season is the part of a year with suitable temperature and sufficient moisture for crop normal growth. Whit recognizing the growing period in the region and crop water requirement can adopt appropriate management to better compromise crop with climate limitations in rainfed agriculture. In the research, the length of growing period in Abhar area using linear interpolation and climatic data was investigated. Besides that, crop water requirement, potential yield, and yield reduction in heavy, medium, and light soil texture for rainfed winter wheat and spring barley were studied using FAO method and long-term synoptic information. Results showed that the length of growing period in terms of moisture was estimated 179 days that its beginning and ending were 1st November and 28th April, respectively. But, considering air temperature and crop critical temperature, from beginning of December to end of February was not involved in the growing period. Therefore, the length of the growing period was declined to 89 days. The humid period was calculated 38 days that its begging and ending were 9th December and 15th January, respectively. Efficient rainfall, crop water requirement, and crop irrigation requirement during winter wheat growing cycle were 89, 611.2, and 522.4 and during spring barley growing cycle were 41.8, 390.3, and 348.5 mm, respectively. Generally, the average, minimum and maximum final yields were estimated for wheat by 1.26, 0.50 and 1.90 Mg ha-1 and for barley by 0.48, 0.18 and 0.80 Mg ha-1, respectively. To mitigate the negative consequences of the shortness of region growing period and its incomplete overlapping with crop growth cycle, measures such as optimum rainwater harvest, sowing in time, improving water use efficiency, selecting drought-resistant or short-season cultivars, and using conservation tillage practices to maintain water are suggested to reach sustainability in rainfed crop production.