جستجوی مقالات مرتبط با کلیدواژه « ردپای آب سبز » در نشریات گروه « اکولوژی »

After wheat, rice has the most important role in human nutrition. Despite the vital importance of its cultivation, high water consumption and water shortage crisis, the sustainability of the cultivation of this grain has faced many problems. Therefore, the purpose of this study is to investigate the water footprint and water use efficiency of rice among the provinces in order to move towards crop sustainability.

Methods & Materials: 

In this study, water footprint index was used to calculate water use efficiency in rice production. For this purpose, first the water footprint components for the provinces of the country were calculated and then the water use efficiency was calculated.

The results of calculating water footprint showed that the lowest water footprint is related to Mazandaran and Gilan provinces and the highest water footprint is related to South Khorasan and Sistan & Baluchestan provinces. Also, the highest and lowest amount of green water footprint is related to Gilan and South Khorasan province, respectively. The results of water use efficiency calculation showed that Mazandaran (0.511) and Gilan (0.422) had the highest efficiency and South Khorasan (0.135) and Sistan & Baluchestan (0.171) had the lowest efficiency.

By comparing the water footprint components among the provinces of the country, it is cleared that the ratio of blue, green and grey water footprint in total water footprint is 45-53%, 6-25% and 0-15%, respectively. Also, the total water footprint of the country was obtained in the range of 1958 and 2758 m3 per ton.

Management of water consumption in arid and semi-arid regions in recent years has been considered a key issue in the field of water resources management. Zirkoh and Ghaenat counties are the hot spots of water consumption in the region. Water footprint and virtual water are critical indicators for water resources management. Therefore, the development of the cropping pattern with high water requirements has led to a negative water balance in the Ghaenat and Zirkoh counties. To prevent the negative consequences of this crisis, it is necessary to consider the restriction of cropping pattern with high water requirements in the region, as well as the assessment of water footprint and virtual water of agricultural products. Also, one of the strategies for managing and optimizing the consumption of water resources in the region is to determine the appropriate cropping pattern with regard to the local conditions. Therefore, this study has been conducted with the aim of calculating the components of water footprint and virtual water in the cropping patterns of Zirkoh and Ghaenat counties and determining the optimal cropping pattern for planting crops from the perspective of water footprint.

In this study, the amount of virtual water and green, blue, gray, and white water footprint for wheat, barley, potato, sugar beet, cotton, alfalfa, and saffron were calculated in the current cropping pattern and at multi-objective nonlinear programming (MOP) approach with the objectives of maximizing net profit and minimizing virtual water, green, blue, gray and white water footprint as the optimal cropping pattern in Ghaenat and Zirkoh counties. The study area was irrigated areas of Zirkoh and Ghaenat counties during 2017.

The results showed that the indices of virtual water and water footprint components in Zirkoh county were higher than Ghaenat county. Also, in two counties, the blue water footprint was more than the green water footprint and the results showed that a large amount of water resources in this area is spent on the production of cotton. In all studied crops, blue water footprint was more than other components of water footprint, which shows the reliance on surface and sub-surface water resources. The results also showed that the area under cultivation of potatoes, melons, and barley in the multi-objective pattern of Ghaenat and the area under cultivation of melons, sugar beets, potatoes, watermelons, alfalfa, and saffron increased compared to the current cropping pattern. Reduction of area under cultivation of cotton, alfalfa, watermelon in Ghaenat county and cotton, wheat and barley in Zirkoh county by 50% in the multi-objective crop pattern were other important results. By determining the optimal cropping pattern, the environmental effects of the agricultural sector on water resources could be reduced, so that the implementation of this pattern in the region reduced virtual water by 26%, blue water footprint by 4%, gray water footprint by 18% compared to the current cropping pattern.

According to the findings of this study, it is necessary to pay attention to the environmental objectives affecting water resources in optimizing cropping pattern. Using the proposed model, in addition to selecting the appropriate model and optimal use of water and land resources, to increase profits and reduce water and virtual water footprint, about 13 million cubic meters of water could be saved compared to the current cropping pattern in the region. Therefore, by implementing the optimal cropping pattern, in addition to reducing the environmental effects, the net income could be maximized of water consumed per cubic meter in the region, and by reducing water consumption, we can help achieve sustainable consumption of limited water resources in the region.

The importance and necessity of planning the rainfed cropping pattern of each region can be attributed to the need for optimal use of rainfall and the provision of solutions to increase production efficiency in rainfed agricultural lands. This study was carried out with the aim of taking into account the water footprint to determine the optimal cropping pattern of rainfed agricultural lands in Ghaenat and Zirkoh counties.

 In this study, the appropriate cropping model of rainfed crops was investigated using multi-objective non-linear programming with the aim of reducing green and gray water footprints while maximizing net profit in counties of Zirkoh and Ghaenat. The data was collected in 2018-2019 through surveys and desk studies from databases and weather stations.

The results showed that the optimal cropping model while maintaining the current income in the region reduced the green water footprint by 1898384 m3 ton-1 and 249886 m3 ton-1 in the multi-objective planning model in the region. The results also showed that by reducing the amount of green water footprint in the cropping model, the amount of economic water footprint in rainfed agricultural land decreases. In general, to achieve economic objectives and reduce the water footprint, in the form of multi-objective planning, the reduction of 121 and 58 ha of cultivated area compared to the current pattern in Ghaenat and Zirkoh is inevitable.