نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه اقتصادکشاورزی، دانشکده کشاورزی، دانشگاه تربیت مدرس، تهران، ایران
2 گروه مهندسی منابع آب، دانشکده کشاورزی، دانشگاه تربیت مدرس، تهران، ایران
چکیده
کلیدواژهها
Extended Abstract
Objective
The degradation of groundwater quality is one of the greatest challenges of the present century (Oki and Akana, 2016). As harmful resources introduced into natural environments and groundwater by humans have caused the salinization of freshwater resources (Bamri et al., 2015) and in addition to surface waters, the quantity and quality of groundwater are also affected by environmental pollutants (Kathy, 2005). With the increase in EC of groundwater and the disruption of the balance of nutrients and ions, the yield of agricultural products and plants decreases. Because the absorption of water by plants decreases, as a result, the plant becomes toxic and burns due to excessive absorption of salts. In addition to groundwater salinity, irrigation water quality, irrigation system, cultivated plants, soil type and groundwater depth are among the factors that cause salinity in the root zone of plants and affect their yield. Statistics show that the EC trend in groundwater in the Urmia Plain has increased from 1380 to 1400 (West Azerbaijan Province Regional Water Company, 1400) and groundwater EC have reached above 700 micro-Siemens/cm. These statistics reveal the need to investigate the effects of salinity on agriculture, especially crop yield.
Methods
Research conducted in the field of groundwater quality and salinity has been examined from three aspects: "hydrological-environmental", "economic-statistical" and "combined". The results of the studies show that the most important factor in the deterioration of water resources is salinity, and determining the salinity of water resources by different methods has a significant impact on decision-making for cultivation in sensitive areas. The present study, using a combination of agricultural and economic methods, investigated the effects of groundwater salinity on the cultivation pattern in the Urmia Plain in the 1400-1401 crop year. For this purpose, the effect of the scenario of increasing groundwater salinity on crop yield was initially investigated with the Aquacrop model, and then the changed yields were entered into the economic model, and based on the changed yields, changes in crop area and the total value of the objective function were determined, and suitable areas for crop cultivation were obtained based on the lowest changes in the total value of the objective function.
Results
First, the AquaCrop agricultural model was simulated for regional conditions and based on the yield potential of five crops in terms of dry weight (DYP) in the Urmia Plain and eight districts. The results of applying the scenario of increasing salinity (decreasing water quality) showed that the yield of all crops decreases. Also, the least change in the yield of irrigated wheat and sugar beet and the greatest change in the yield of corn, sunflower and tomato has occurred. It can be concluded that irrigated wheat and sugar beet are more resistant to salinity than other crops and in severe salinity conditions, these crops can be replaced by sensitive crops. After simulating the yield of crops by applying salinity stress, the simulated yields were entered into the economic model and the economic results of changing the crop pattern were examined.
Discussion
Crops that showed an increasing trend in their cultivated area with increasing salinity were selected as suitable areas for cultivating that crop. Similar to the decrease in the total cultivated area with the application of the salinity scenario, the gross margin was also associated with a decrease of 0.5 to 11 percent compared to the optimal state, resulting in losses for farmers. The results also show that as the salinity of irrigation water increases to a very low level, the total area under cultivation of crops in regions 3, 6, 7 and 8 decreases and increases in other regions, and it is possible to cultivate crops in regions 1, 2, 4 and 5 in high salinity conditions. In general, the salinization of groundwater resources, in addition to the decrease in crop yield, will cause great losses to farmers by reducing gross output. Therefore, by introducing methods to prevent the increase in groundwater salinity of agricultural origin, in addition to maintaining the quality of water resources, the decrease in crop yield can also be prevented.
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
If the study did not report any data, you might add “Not applicable” here.
The authors would like to thank all participants of the present study.
The authors avoided data fabrication, falsification, plagiarism, and misconduct.
The author declares no conflict of interest.
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