Analysis of rainfed wheat farming climatic potential based on RPI index (Case study: East Azerbaijan Province)

In this study, based on precipitation amounts, precipitation time intervals occurrence and evapotranspiration, rainfed Potential Index (RPI) was introduced to assess the capacity of dryland farming areas Which is very important in potential of rainfed issue due to containing the impact of precipitation remaining in soil; since precipitation remaining related to soil water content capacity and will be effective on yield production, therefore, behavior of rainfed wheat yield was discussed against RPI index various in the East Azerbaijan province and a model were developed to estimate the rainfed wheat yield using PRI. The results showed that the highest and lowest mean rainfed potential index ((RPI) ̅) and frequencies of RPI with more than (RPI) ̅ amount were in Maragheh and Sahand plains, respectively. Investigations showed that the precipitation occurrence multiplicity is not representing a high potential alone for rainfed farming. Since, Bostanabad area with the highest occurrence value (945 times) due to high frequency of trace rains (less than 1.4 mm/d) was not showed good yield production in during the study years. Generally, according to that the southern and western regions of province have high and low rainfed farming potential and RPI, respectively. Also, the proposed model calibration coefficients, both in the province scale and all stations except Sahand with P-value less than 0.01 or 0.05 were valid to estimate the wheat yield based on the new presented index.