Simulating the Effects of Climate Change on Phenology and Yield of Maize (Zea mays L.) and Possible Adaptation Strategies under the Climatic Conditions of Kermanshah

Global warming directly affects agricultural production and food security (Ainsworth & Ort, 2010). Temperature controls the rate of plant metabolic processes that ultimately affect biomass production and grain yield (Hay & Walker, 1981). Although farmers are not able to control the climatic conditions, management and changes in factors such as irrigation, soil, crop varieties, activities, and technologies used in the cultivation of crops can reduce the harmful effects of climate change (Moradi et al., 2014). One of the reliable approaches to studying the effects of climate change on agricultural production is using crop growth models. The present study was conducted to simulate the effects of climate change on phonological stages and yield of maize and to investigate the possibility of mitigating the negative effects of climate change on maize by changing the sowing date and selecting suitable cultivars as management strategies for adaptation to climate change in Kermanshah region.

Materials and Methods :

The study was conducted in Kermanshah region conditions. The evaluated traits included days from the sowing date to anthesis, days from the sowing date to physiological maturity, total dry weight, and grain yield. In general, the results of the evaluations showed that the CERES-Maize model can accurately predict the growth and yield of maize cultivars (SC704, Simon, BC678) in different soil moisture conditions. After ensuring acceptable agreement between simulated values with observed values, the evaluated model was used to study the effects of climate change on maize production in the near future (2021-2050) and the far future (2051-2080) climate change according to RCP4.5 and RCP8.5 scenarios and comparing them with baseline conditions (1981–2010). The average of 17 general circulation models was used to simulate meteorological parameters under climate change conditions. The common sowing date for maize in the Kermanshah region is May 5. In this study sowing dates of May 5 and April 26 as early sowing dates, April 15 as the common sowing dates, and May 25 and June 4 as the late sowing dates, and maize cultivars SC704, BC678, and Simon were considered as adaptation strategies to climate change.

The results of simulation showed that regardless of cultivar and sowing date, traits of days from sowing date to anthesis, days from sowing date to physiological maturity, total dry weight and grain yield in the near future climate change in the scenario RCP4.5 varied as -2, -1.5, 2.7, and 3.3% and in the RCP8.5 scenario varied as, -2.9, -2.8, -0.66, and -3.6% compared to baseline conditions, respectively. These values for the RCP4.5 scenario in the far future climate change condition were -5.2, -5.4, -7.1, and -16.2 and for the RCP8.5 scenario were -8.8, -9.8, -23.1, and -45.83%, respectively. In both near and far future climate changes and under both scenarios, by sowing the studied cultivars at late dates (May 15 and May 25) compared to the early dates (April 15 and April 25) and common date (May 5), the length of the developmental period was shorter but other traits such as total dry weight and grain yield were higher. Among the studied cultivars, in both future climate changes and scenarios, the Simon cultivar had the highest grain yield. The highest duration of developmental stages and total dry weight belonged to SC704.

In general, if any of the RCP4.5 and RCP8.5 scenarios occur in the near and far future climate change periods, the sowing of the Simon cultivar should be in late dates on May 25 and will have the highest grain yield. Therefore, it can suggest as a suitable strategy to reduce the negative effects of climate change on maize production in the Kermanshah region.