عنوان مقاله [English]
Climate plays a key role in the successful production of horticultural products for the global trade. Horticultural activities are highly dependent on local weather conditions. The study of the phenomenological behavior of the products as part of the impact of environmental conditions is important, because for optimal production as well as more appropriate management, it is essential to know the phonological stages and changes in the product.
Materials and methods
In this study, the ECMWF database has been used for observation data of Semirom and Urmia stations during 20-year period (1996-2001). To evaluate the accuracy of ECMWF data with the observation data of the Iranian Meteorological Organization during the common time interval with the nearest point of ERA-Interim to the stations studied, we have used the Pearson Correlation Coefficient (R), Coefficient of Determination (R2), Mean Squared Error (MSE), Root Mean Square Error (RMSE), and Normalized Root Mean Squared Error (NRMSE). The most important factor in determining the need for water is the accurate ETo estimation in each region, so the potential evapotranspiration (ETᴼ) values were calculated using the Penman-Monteith FAO method. To investigate the effects of climate change on water requirement and duration of growth, the daily micro scale dynamic data of the CORDEX project with a precision of 44% * 44% for the output of the ICHEC-EC-EARTH model under the two lines of 4.5 and 8.5 (RCP) was used for the period (2017-2037). In order to reduce the errors in the model estimates, the post-processing action of the estimated events was fulfilled. The water requirement and growth season length of the apples was also evaluated. Given the highest amount of apple cultivars in the study area is autumn, the type of late fall apple is selected for evaluation. According to correlation of each step of growing apples with thermal operating temperature, length of growing season and vegetative stages of apple tree were calculated using GDD.
Results and discussion
The statistical results between ERA-Interim data and observational data at the stations were examined and the accuracy of the database was confirmed for both stations. In the next section, in order to select the best model for the study area, the data of the base year of the growth season of the CORDEX project models was compared with the observational data. The ICHEC-EC-EARTH model has a lower error rate than the other two. The post processing of historical events has been able to greatly increase the model's performance data. The results of the two man-Kendall and Sen's slope at the Semirom station on the ETo observations were reduced during the growing season, but in the Urumia station, the slope is positive and incremental. The evapotranspiration potential was observed in the growing season, under the RCP4 / 5 and RCP8 / 5 trajectories for the stations. This is typical of an incremental trend. At the Uromiyah station, the results of the ETo on the growth stages of the apple tree indicate an increasing trend for observational data in all stages. For the estimated data, the effective rainfall season in Urumieh station is more than Semirom. Therefore, during the growth season of the apple tree, the Semirom station will need more water in the observation period and years of forecasting than the station in Orumiyeh. At both stations, in the observation period and the estimated data, the rainfall level is effective in the germination stage, more than other stages. In the course of 8/8 for both effective precipitation stations will be increased in the observation period. Given the evapotranspiration and precipitation during the growing season of apples, the results of simulations showed that under climate change conditions compared with the base period, the need for irrigation of apple trees at Urmia and Semirom stations should be increased under both scenarios. The results from the comparison of the growth period of the base period and the estimated data at the stations under both scenarios indicate a decrease in the growth period in the future. The trend was not statistically verified. Earlier heat supply due to increased temperature has led to some shortening steps. Decrease in the growth period in the scenario is 5.8 and more than the 4.5scenario.
Based on the evaluation methods, the ECMWF data estimation error with observational data was negligible, and the database for the study stations can be verified. The results showed that evapotranspiration in both stations are increasing during the growing season. The ETo increase in the growth season of the apple tree was predicted from the base period for the trajectories of 4.5 and 8.5 for the Semirom at 4.14.7 and 7.99.7, respectively, and for Orumiye Station, the values are 26.5 and 11.8, respectively. However, this increasing process will raise the apple's need for water. The highest amount of evaporation and water requirement in the observed and estimated data has been occurred in the period of growth. At this stage, the lowest effective rainfall and the highest average temperature have occurred but generally the percentage of upcoming changes of germination stage was more than other stages. Earlier heat supply will reduce the growth period of the apple tree. In fact, the plant will complete its growth and reproduction cycle earlier, resulting in reduced yield, reduced quality and color, increased temperature and increased water requirement. Earlier heat supply due to increased temperature has led to some shortening steps.