Mehdi Akbari; Hamed Najafi Alamdarlo; seyed habibollah moosavi
Abstract
Climate change is one of the natural occurrences that cause temperature rise, reduced rainfalls, change in water balance, decline in production level, and frequent droughts. Therefore, predicting and evaluating the effects of climate change and drought could be very effective for future decision making. ...
Read More
Climate change is one of the natural occurrences that cause temperature rise, reduced rainfalls, change in water balance, decline in production level, and frequent droughts. Therefore, predicting and evaluating the effects of climate change and drought could be very effective for future decision making. According to this approach, in this study, the effects of climate change and drought on cropping pattern and income risk effects in Qazvin plain were investigated. The LARS-WG model was used to simulate climate variables (temperature and precipitation) in the future, as well as their changes in the A1B, A2 and B1 climate scenarios. Also, the Standard Precipitation Index (SPI) was used to determine drought periods and water volume changes. Then, using the mathematical programming approach and compilation of the MOTAD-TARGET with PMP model, the cropping pattern was simulated in climate scenarios and drought periods and the risk effects of these scenarios were investigated. The results show that in all three climate scenarios, temperature increases and precipitation decreases, and cropping pattern changes toward crops with higher income stability. In drought scenario, due to reduced water volume, the cropping pattern tends to crops with less water requirements, and crops with higher income levels have less changes. Income risk, in the worst drought scenario (very severe drought) and climate change (scenario A2 during the period 2040-2049), would decrease by 68.1% and 6.377%, respectively. By reducing the income risk, the gross margin will be reduced. Considering the economic effects of climate change and drought in long-term, it is recommended to use drought and heat resistant varieties. Also, the area under cultivation of crops such as barley, corn, sugar beet, and tomato may be increased as they have a more stable income.
mohammad ali asaadi; Sadegh Khalilian; seyed habibollah moosavi
Abstract
The aim of this study was to determine the optimal cropping pattern in irrigation network of Qazvin plain with emphasis on deficit irrigation policy and reduction of fertilizers and chemical pesticides. For this purpose, the Positive Mathematical Programming approach (PMP) and Maximum Entropy Technique ...
Read More
The aim of this study was to determine the optimal cropping pattern in irrigation network of Qazvin plain with emphasis on deficit irrigation policy and reduction of fertilizers and chemical pesticides. For this purpose, the Positive Mathematical Programming approach (PMP) and Maximum Entropy Technique (ME) were used. The results of the first option (5% deficit irrigation in wheat, barley, grain corn, fodder maize and Sugar beet at the ripening stage, and 5% deficit irrigation in the vegetative growth stage for alfalfa simultaneously with5% reduction in fertilizers and chemical pesticides) showed that sugar beet, alfalfa, grain corn and fodder maize were be desirable for cropping pattern due to their high economical profit in compared to wheat and barley. Also, applying this policy leads to an increase in gross margin (4.5%) and a reduction in water consumption (5.1%) in the agricultural lands of the region.As a result of the implementation of the second scenario, the cropping pattern goes towards products that have a higher economic margin due to their lower irrigation water consumption. This scenario leads to 3.6% increase in gross margin and 17.2% reduction in water consumption. Other results of the research showed that due to the application of these policies in PMP, the sustainability indicators of water resources, fertilizers and chemical pesticides are less than the current values for the region's present cropping pattern. The calculated environmental index revealed that high consumption of water, fertilizer, and other chemical inputs are a barrier to achieve sustainable agriculture.