كليدواژه :
بهينه‌سازي , سود خالص , فرصت اشتغال , مصرف آب
چكيده فارسي :
اين مقاله به ارزيابي پايداري در سيستم زراعي دشت بجستان در استان خراسان رضوي و تعيين مناسب‌ترين الگوي كشت متناسب با آن مي‌پردازد. براي تلفيق ابعاد سه‌گانه محيطي، اقتصادي و اجتماعي، دو معيار نسبي به عنوان شاخص‌هاي بررسي پايداري سيستم تعريف شدند. اين دو معيار شامل حصول بيشترين عايدي اقتصادي و ايجاد بيشترين فرصت‌هاي اشتغال به ازاي هر واحد مصرف آب، هستند. بهينه‌سازي نسبت‌هاي «سود خالص به مصرف آب» و «ايجاد اشتغال به مصرف آب»، با بهره‌گيري از مدل‌هاي برنامه‌ريزي رياضي يك‌هدفه و چندهدفه كسري انجام شد. با هدف حداكثرسازي سود، شاخص‌هاي پايداري سود به مصرف آب و اشتغال به مصرف آب در مدل كسري به‌ترتيب 3/17 و 0/19 درصد نسبت به مدل خطي افزايش داشت. با هدف حداكثرسازي اشتغال شاخص‌هاي پايداري بالا به‌ترتيب 2/25 و 1/22 درصد افزايش داشت. در رويكرد چندهدفه برنامه‌ريزي آرماني، شاخص اشتغال به مصرف آب در مدل كسري، 4/32 درصد بيشتر از مدل خطي بود، ولي نسبت اشتغال به مصرف آب 5/42 درصد افزايش نشان داد. در ادامه با مقايسه كارايي اقتصادي و اجتماعي هر واحد مصرف آب در سناريوهاي مختلف، مناسب‌ترين الگوهاي كشت منطقه با توجه به منابع موجود آب و خاك و نيروي انساني مشخص شد.
چكيده لاتين :
Stability of soil and water resources in agriculture, above all depends on the type of resource utilization and cropping pattern. Nowadays, maximization of factors such as income, job opportunities and minimization of costs as the economic and social aspects along with the limitations of arable land and water has attracted the attention of planners and managers of agricultural projects. One of the most important questions is the issue of sustainability, how to evaluate, measure and analyze sustainability? One of the methods to assess the stability is mathematical programming approaches. Application of this model for agricultural planning has a long history and a wide range. But using a particular type of this model to assess the sustainability, means the fractional model is a new topic. Lara and Stancu-Minasian (1999) examined the theoretical aspects of this model in a research titled as “Fractional programming: A tool for the assessment of sustainability”. As mentioned above, there are three main objectives for sustainable crop pattern, maximization of income and job opportunities and minimization of costs (In this case water consumption). Using fractional programming provides the possibility to make three goals in two goals which include maximization of “the net profit/water consumption” and “making job opportunity/water consumption”. In this way, the number of solutions is lower and therefore the decision-making process is easier. Fractional programming for planning and optimization cropping pattern has not been done yet. This paper is being studied to evaluate the stability in the agricultural systems of Bajestan plain located in the Razavi Khorasan province; and also determine the best cropping pattern. There are about 10,000 hectares of agricultural lands in the Bajestan plain. These lands are cultivated in seven major crops which include barley, saffron, wheat, pistachios, cotton, pomegranate and melon. Now the area under cultivation of these crops is 2250, 1630, 1500, 1400, 1200, 1350 and 670 hectares, respectively. In this region, about 70% of the working population are employed in agriculture.
To verify the effectiveness of the fractional models first of all, three mono goal linear models were prepared. The goal of each of these three models was maximization income and maximization of job opportunities and minimization of water consumption. By solving these models, three cropping patterns A1, B1 and C1 were obtained. For combination the triple dimensions of social, economic, and environmental, two relative criteria have been explained as the indications to evaluate system stability. Thus, in the next step, by dividing each of the two functions (maximization of income and maximization of job opportunities) to water consumption, two new objective functions were obtained in the form of fractional model.
