Investigating the effects of climate change on the growth period and water Case study: Semirom and Urmia stations requirement of the apple tree

Introduction Climate plays a key role in the successful production of horticultural products in the global trade. Horticultural activities are highly dependent on local weather conditions. The study of the phenomenological behavior of products as part of the impact of environmental conditions is important, because in order to achieve optimal production as well as more appropriate management, it is essential to know the phonological stages and changes to the product. Methodology In this study, the ECMWF database has been used for observation data of Semirom and Urmia stations during 20-year period (1996-2001).To understand and 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, 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 effect 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 apples were also noted. Then, considering that the highest amount of apple cultivars in the studied areas is autumn, the type of late fall apple is selected for evaluation. According to correlate each step of growing apples with thermal operating temperature, length of growing season and vegetative stages of apple tree were calculated using GDD. Results The statistical results between ERA-Interim data and observational data at the stations were examined and the accuracy of the database data was confirmed for both stations In the next section, in order to select the best model for the studied areas, 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 The ICHEC-EC-EARTH has a lower error rate than the other two. Do post processing of historical events has been able to greatly increase the model's performance data. The results of 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 observed in the growing season, under the RCP4 / 5 and RCP8 / 5 trajectory for stations, shows 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 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 was more than other stages. In the course of 8/8 for both effective precipitation stations will increase compared to the observation period. Considering the evapotranspiration and precipitation during the growing season of apples, the results of simulations showed that under climate change conditions compared to the base period, the need for irrigation of apple trees at Urmia and Semirom stations was 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, which their trend was not statistically verified. Earlier heat supply due to increased temperature has led to some shortening steps. Decreasing the growth period in the scenario is 5.8 more than the scenario of 4.5. Conclusions Based on the evaluation methods, the ECMWF data estimation error with observational data was negligible, and the database data for the studied stations can be verified. The results showed that evapotranspiration in both stations is increasing during the growing season. The ETo increase in the growth season of the apple tree stations was predicted from the base period for the trajectory of 4.5 and 8.5 for the Semirom 4.14.7 and 7.99.7, respectively, and for Orumiye Station, 26.5 and 11.8, respectively, and 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.