عنوان مقاله [English]
An increasing number of studies have reported on shifts in timing and length of the growing season, based on phonological, satellite and climatologically studies. The evidence points to a lengthening of the growing season of ca. 10–20 days in the last few decades, where an earlier onset of the start is most prominent. This extension of the growing season has been associated with recent global warming. Changes in the timing and length of the growing season (GSL) may not only have far reaching consequences for plant and animal ecosystems, but persistent increases in GSL may lead to long-term increases in carbon storage and changes in vegetation cover which may affect the climate system. This investigation has presented 49 years inputs of temperature from 31 synoptic stations of Iran. With the aim of these study is an investigation the trend of time changes of starts and end season growing length of Iran. The growing season start (GSS) is defined as the first day of the first 5-day period with a daily min temperature greater than thresholds and growing season end (GSE) is defined as the first day of the first 5-day period with a min temperature of less than thresholds. The start and end dates of temperature is a 5˚ and 10˚ thresholds. Based on agricultural year with jealousy coding was extracted. Homogenize the series using run-test experiment were determined and accomplished in the way of auto regression from rebuilding of missed data by way of man-Kendal test the randomness of data was examined and the series that had change or trend with %5 confidence interval were recognized then with graphically man-Kendal test and moving mean of 5 year, circumstances and the start time of trend or changes were determined and the values of changes were calculated. The results show more changes in series associating with start and end of temperatures.