Abstract

Abstract Analysis of raining days is one of the most significant elements of weather forecasting concerning agricultural section, since rainfall is the most unstable factors and shortage or rainfall during growing season may create heavy damages on agricultural section, particularly on dry farming. Necessity of monitoring and analysis of this phenomenon could be demonstrated when we consider that a great part of agricultural lands depends on rainfall (amount and number of times) directly. Meanwhile, the significant performance of farming products will be related to raining method also in irrigation agriculture section. In the present study, number of raining days in Qazvin synoptic station, to analyze and study pathologically wheat cultivation by dry farming in the province, statistical models were used. Results of statistical analysis of number of raining days demonstrated that number of raining days in wet years in autumn cultivation season with recurrence interval of 5, 10, 25 and 50 year based on 29, 32, 39 and 44 days, respectively. Furthermore, in dry years, number of raining reliable days can be 8, 4, 0 and 1 day. In this regard, to investigate and study pathologically dry farming in the province, a statistical analysis was performed about raining days during growing season for wheat product. Findings of the analysis showed that in dry periods, dry farming is not appropriate and no reliable rainfall will be occurred during growing period.