In Uzbekistan, since the late 1950s, the world’s 4th largest lake, the Aral Sea, has been shrinking. The reason is the inflow deviation for irrigation of cotton plantations spread across the arid region.
Conventional agriculture alone is the largest contributor to ecosystem degradation and water scarcity. Also, land irrigation has helped boost agricultural yields and production in arid and semi-arid environments. Yet when water extraction is done without control, cases such as the Aral Sea in Figure 1 are seen more often.
Agriculture is responsible for 70% of freshwater withdrawal worldwide. As the population grows, the food system must feed more people, thus increasing water demand. Research shows that future socio-economic development and climate change may impact regional and global irrigation requirements, therefore on agricultural water withdrawals. Increased water demand for irrigation over many years, caused decreased water flows, land clearing, and overall stream water quality deterioration[1]
The need to cover forecasted urban and industrial water considers diverting water away from crop irrigation. This, in turn, results in a direct impact on food security. Improving yields to feed future populations with sustainable water use in agriculture strongly depends on augmenting water productivity in crops.
The threat to food security comes as a call for attention to unsustainable agricultural water use. Improved and adequate water management, as well as enhanced irrigation infrastructure, starts to become a requisite of agricultural practices of any sort. Exploring and applying different alternatives can minimize the impact of water demand for food production.
Currently, world food production comes from around 1.5 billion hectares, from which 1.1 billion hectares are rain-fed with no irrigation systems, as shown in Figure 2. That land extension covers around 80% of the world’s physical agricultural area and produces up to 60% of the world's essential food[1].
![Figure 2: Global rain-fed croplands along with irrigated crops and other land use/land cover[2]](https://bosaq.com/wp-content/uploads/2022/06/Figure-2-1.jpg)
Figure 3, on the other hand, shows where different crops come from. A comparison between both images pictures an idea of the threat posed by water scarcity and lack of resources management in different parts of the world when it comes to food security and rain-fed agriculture.
![Figure 3: World agricultural crop diversity distribution[3]](https://bosaq.com/wp-content/uploads/2022/06/Figure-3.jpg)
This situation is especially detrimental to people living in rural areas. Rain may be plentiful for some farmers, but in many places, it falls out of season and is lost during droughts. Extreme weather events can be devastating for crops in the field. If measures are taken, the result is food prices increase, which affects mostly the most vulnerable share of the population. Simple solutions as rainwater harvesting and diverting water from rooftops into storage are a few simple tactics that can stabilize rain-fed crop production while relying on irrigation at a minimal scale.
Strategies to ensure food security include expansion of rain-fed and irrigated areas to meet the food demand in 2050. On the contrary, the introduction of new and enhanced technology to improve yields and maximize water productivity would skip the massive 53% expansion of rain-fed land, instead of the projected 7%. Although the land is available, it means converting natural ecosystems to agricultural land. Irrigated land could contribute to 55% of the total value of food supply by 2050, compared to the current 45%. Yet that expansion would require 40% more water to be withdrawn for agricultural purposes, threatening aquatic ecosystems and fisheries.
Irrigation can turn uncultivable land into fertile land, just as they initially did with the Aral Sea inflow and converted unfertile land into cotton fields. Irrigated systems support around 30% of crop production with 10% of the total water used for agriculture[5], and they provide a compensation for the productivity difference between high and low yield fields. However, poorly managed irrigation systems result in soil salinization.
Irrigation systems are sensitive to water quantity and quality. The latter plays a relevant role in the sustainability of irrigated lands, especially in soil salinization.
In the world’s driest areas, the soil and water used for agriculture are naturally salty. Salty environment, inefficient irrigation, and poor drainage lead to waterlogging. As a consequence, the water table moves up salts, also bringing up the salts in the subsoil nearer the surface as shown in Figure 4. During evaporation, the plants’ roots are left with a higher salt concentration around, preventing them from absorbing water, restricting growth, and polluting drinking water supplies, as shown in Figure 4.
Salinization causes soil productivity to be reduced along with crop yields. The once perfect, productive soil is now unfertile and deserted, just as shown in Figure 5.
The world’s salt-affected land translates into a loss of productivity equivalent to $12 billion per year[5]. As water quality keeps deteriorating, that number is expected to grow, unless alternative sources of water irrigation are deployed, especially in regions with limited freshwater resources.
Several alternatives arise when it comes to soil salinization prevention. Proper and sustainable water resources management, along with efficient water distribution networks are necessary to minimize soil salinization. If measures like these are not adopted, using poor quality irrigation water results in the need for extra water to prevent salt accumulation in the soil[6].
Water desalinization and wastewater reuse provide opportunities to avoid depletion and contamination of natural water resources. Water treatment for agriculture is already practiced in several parts of the world, such as Spain. The Spanish agricultural industry utilizes about 71% of the reclaimed wastewaters in the agricultural industry, as well as a smaller share of desalinated water[6].
Introducing membrane technology in irrigation systems provides the opportunity of producing water with adequate nutrients concentration for high-crop production in a sustainable way. Membranes' flexibility to treat different water pollutants and low energy consumption make them stand as one of the best available technologies for wastewater treatment and reuse in the agricultural sector[6].
Treated saline water or reused wastewater can be used for sustainable food production thanks to membrane technology. Their use leads to a minimization of freshwater use, while at the same time reducing the volume of polluted water that is released to the environment. The technology is already popular in different areas of the world underwater stress, either for water desalination or wastewater treatment for the irrigation of edible and non-edible crops.
At BOSAQ we value every water drop as a finite resource upon which food security relies. We envision a sustainable food system capable of feeding the world without exhausting our water resources. Our team of experts combines optimal water management solutions with advanced decentralized membrane technology systems fed with renewable energy to purify the water source you have at hand and adjust it to your needs.
[1] M. A. Hanjra and M. E. Qureshi, “Global water crisis and future food security in an era of climate change,” Food Policy, vol. 35, no. 5, pp. 365–377, Oct. 2010.
[2] C. M. Biradar et al., “A global map of rainfed cropland areas at the end of last millennium using remote sensing and geospatial techniques,” in Geoinformatics 2006: GNSS and Integrated Geospatial Applications, 2006, vol. 6418, p. 64181Q.
[3] C. K. Khoury et al., “Origins of food crops connect countries worldwide,” Proc. R. Soc. B Biol. Sci., vol. 283, no. 1832, pp. 1–9, Jun. 2016.
[4] Y. H, “A Review on Relationship between Climate Change and Agriculture,” J. Earth Sci. Clim. Change, vol. 07, no. 02, pp. 1–8, Feb. 2015.
[5] S. Assouline, D. Russo, A. Silber, and D. Or, “Balancing water scarcity and quality for sustainable irrigated agriculture,” Water Resour. Res., vol. 51, no. 5, pp. 3419–3436, May 2015.
[6] C. A. Quist-Jensen, F. Macedonio, and E. Drioli, “Membrane technology for water production in agriculture: Desalination and wastewater reuse,” Desalination, vol. 364. Elsevier, pp. 17–32, 05-May-2015.
