مدل‌سازي بيوفيزيكي- اقتصادي جامع اقليم و كشاورزي (مطالعه موردي: حوضه آبخيز رودشور)

Comprehensive Biophysical-Economic Modeling of Climate and Agriculture (Case Study: Roodshour Watershed)

هدف اين مقاله مدل‌سازي بيوفيزيكي- اقتصادي جامع اقليم و كشاورزي در حوضه آبخيز رودشور با استفاده از مجموعه داده ­هاي پانل (سري زماني) مربوط به متغير اقليمي بارش طي 1395-1365 و مقطعي سال پايه 95-1394 مي‌باشد. براي دست‌يابي به نتايج كاربردي، مدل‌سازي با تلفيق دو بخش بيوفيزيكي و اقتصادي تحت سناريوهاي آزمايش ملايم، متوسط و شديد با استفاده از نرم‌افزار گمز صورت گرفت. نتايج نشان داد الگوي رفتاري متغير اقليمي بارش در حوضه آبخيز رودشور پس از سال 1380 با روندي كاهشي همراه بوده و با تغيير اقليم ناشي از كاهش بارش تحت سناريوهاي ملايم تا شديد، منابع آب منطقه 5/75 تا 13/8 درصد، توليدات كشاورزي 3/60 تا 8/54 درصد و سود ناخالص كشاورزان 2/71 تا 8/04 درصد كاهش مي‌يابد؛ اما، ارزش اقتصادي هر مترمكعب آب آبياري نسبت به سال پايه 5/13 تا 12/7 درصد افزايش مي‌يابد. براي حفاظت از منابع آب اين حوضه، تعيين مجدد نرخ آب­ بها براساس برابري، آيش­ گذاري اراضي و تجهيز سيستم‌هاي نوين آبياري پيشنهاد مي­ شود.

In this study using panel dataset (combining the time series data related to the climatic variables of rainfall during 1986-2016 and the cross sectional data related to the base year 2015-2016) the comprehensive biophysical-economic modeling of climate and agriculture in Roodshour watershed basin was studied. In order to achieve the applied results, modeling is done by combining two parts of the biophysical (the products yield estimation model) and the economic (positive mathematical programming model) under mild, moderate and severe testing scenarios and with advanced programming in the GAMS 24.7 software environment. The results show that after year 2001, behavioral pattern of rainfall climate variable was accompanied with a decreasing trend in the Roodeshoor basin. With occurrence of the climate change resulting from rainfall reduction under mild, medium and intense scenarios, the available water resources decreased 5/75 to 13/8 percent, agricultural products decreased 3/60 to 8/54 percent and farmers' gross profit decreased 2/71 to 8/04 percent. But the economic value of irrigation water increases 5/13 to 12/7 percent ratio to base year. Finally, in order to protection of the water resources in the Roodeshoor basin and coping with the effects of climate change, Redetermination of the rate of water charge to farmers on the basis of equality consideration, fallow-lands and equipping farms to modern irrigation systems were proposed.