اثر تغییراقلیم بر رشد و عملکرد گیاه پنبه (منطقه مورد مطالعه: دشت بیرجند)

مطالعه اثرات تغییراقلیم بر محصولات کشاورزی می‌تواند موجب بهبود و توسعه راهبرد‌های مدیریتی در ارتباط با نیاز‌های مهم کشاورزی در آینده و اتخاذ روش‌های سازگاری و کاهش اثرات سوء تغییراقلیم بر بخش کشاورزی گردد. هدف این پژوهش پیش‌بینی اثرات تغییراقلیم آینده بر عملکرد پنبه در منطقه بیرجند است که مدل گردش عمومی bcm2 تحت دو سناریوی انتشار b1  و a1b در سه دوره (2025 تا 2050، 2050 تا 2075 و 2075 تا 2100) برای پیش‌بینی شرایط اقلیمی آینده مورد بررسی و برای تولید پارامترهای اقلیمی روزانه مدل ریزمقیاس‌نمایی lars-wg مورد استفاده قرار گرفت. داده‌های اقلیمی روزانه به‌دست آمده از خروجی lars-wg به‌عنوان ورودی برای مدل dssat (مدل شبیه‌سازی محصول زراعی) به‌منظور شبیه‌سازی رشد پنبه تحت اقلیم آینده استفاده شد. شبیه‌سازی بیان‌گر این بوده است که در مقایسه با دوره پایه، تغییراقلیم عملکرد پنبه را (از 14.73 تا 18.53 درصد) افزایش و طول فصل رشد پنبه را کاهش داد. دلیل اصلی افزایش عملکرد پنبه را می‌توان به افزایش غلظت دی‌اکسید‌کربن نسبت داد.

impact of climate change on cotton growth and yield (case study: birjand plain)

the aim of this research is to predict the effects of future climate change on cotton yield in birjand region. in this research, the bcm2 general circulation model under two release scenarios b1 and a1b in three periods (2025 to 2050, 2050 to 2075, and 2075 to 2100) was examined to predict future climate conditions and to generate daily climate parameters of the lars-wg microscale model. daily climate data obtained from lars-wg output were used as inputs for dssat model (crop simulation model) to simulate cotton growth under future climate. the selection and preparation of a suitable plot of land for the implementation of the project was done in the beginning of october 2018. the intended experimental design was factorial split plots. the dssat model provided acceptable results for cotton yield and phenological stages, and this success was confirmed when the values simulated by the model were compared with the data collected from the field experiments. the maximum nrmse is related to hw simulation, which is calculated as 9.7%. the value of this index for simulating the phenology stages is much lower and its value is reduced to 1.5%. the results of this research show that the dssat model can be a promising tool for predicting yield, leaf area, nitrogen accumulation, phenology and biomass of different cotton cultivars and other crops grown in the region. it seems that this study is useful and appropriate for farmers and their making decisions. the results of the simulations showed that due to future climate change and increase in temperature and carbon dioxide concentration in birjand city, cotton yield will increase. on average, under all scenarios, the average yield of cotton will increase by 15% in the period of 2025 to 2050, by 15.44% in the period of 2050 to 2075 and by 18.15% in the period of 2075 to 2100. the simulation has shown that climate change increased cotton yield (from 14.73 to 18.53 percent) and reduced the length of the cotton growing season. the main reason for the increase in cotton yield can be attributed to the increase in carbon dioxide concentration.