The water we eat daily through the food we consume is at least 1,500 times more than our daily drinking requirement. If this trend continues, we risk being water-stressed, impoverished, and hungry by 2030.

The Earth’s system relies heavily on water as it is essential for sustaining all life forms that exist therein, including those related to our food systems. However, the availability of clean water is decreasing. By 2050, it is estimated that a significant portion of the world's population, half of global grain production, and nearly half of the world's Gross Domestic Product could be jeopardized due to water stress. Water consumption is projected to account for 40% of global water usage, encompassing all freshwater sources. This challenge is amplified by the siloed coordination between key stakeholders involved in the food and water systems, giving rise to discrepancies in strategies for water management, food security, and nutrition challenges.

Climate change and other environmental and societal shifts, such as alterations in land use, irrigation systems, infrastructure development, biodiversity loss, and changing lifestyles and diets, worsen the weak coordination between food security and water management efforts. An example of this is evident in the Strategic National Pathway for Food Systems Transformation established by the Indonesian Ministry of Development Planning (BAPPENAS), which neglects the role of water, sanitation, and hygiene (WASH) as a key element to support the achievement of food systems sustainability. WASH interventions are foundational nutrition-related public health measures that help combat environmental enteropathy, infectious disease control, and agricultural instability. Yet, with a decline in clean water sources, each relevant sector struggles to realize such interventions at scale, which makes water resources management all the more important for a more adaptive and market-based management. 

Interactions between water and food systems

Since the 1900s, human activities have been contributing to the loss of over half of the world's natural wetlands as well as forest degradation that has had unfavorable effects on streamflow. Soil health plays a crucial role in supporting terrestrial ecosystems, which are vital for the functioning of aquatic ecosystems. Healthy soil provides a range of ecosystem services, including regulation of water flow, provision of nutrients, and support for cultural practices–all of which contribute to the overall health and resilience of freshwater ecosystems. 

As intensive water usage increases, so does water scarcity. Accounting for over 70% of total freshwater usage and 85% of irrigation, the agricultural sector makes a considerable contribution to water scarcity. Despite this high water demand, irrigated crop areas have managed to produce 40% of the world's food output, utilizing only about 20% of the total cropland available to feed the global population.

Irrigation for agricultural practices uses water either from groundwater (springs or wells) or from surface water (rivers, lakes, or reservoirs).

Of all the water used for irrigation in agriculture, at least half of it is wasted.

Water wasted from irrigation could pollute freshwater sources because it could already contain agricultural fertilizer run-off, pesticide, and livestock effluents, making the water not viable for human use. This could affect human health by increasing the risk of various diseases associated with the reuse of polluted water, including exposure to salts, organic pollutants, toxic metals, and microbial pathogens like viruses and bacteria. Not only humans, soil and plants could also be contaminated by poorly treated wastewater high in toxic organic/inorganic chemicals, microbial pathogens, and in the long term plastic nanoparticles.

As more areas are facing water scarcity, soils that are used for agricultural practices contain more salt because irrigation water and fertilizers leave behind a tiny portion of salt after the water evaporates. Furthermore, water used for agricultural practices could experience salinization as the sea level rises and is brought by rivers used for irrigation. This could cause high levels of sodium and stress for the crops because of osmosis, which is poisonous for the crops and makes it hard for them to absorb water, respectively. Additionally, salinization could also slow down plant growth and lower the amount of yield of crops. 

Saltwater farming for the future?

One way to address water waste is by reusing it, although several considerations must be taken into account for its safe reuse. Safe irrigation practices must be implemented by reducing chemicals, using technical and natural water treatment processes (eg, removing chemicals with PBT and/or PMT elements), embracing ethical agricultural practices, and implementing preventive measures, such as via transfer of knowledge to stakeholders involved.

A more innovative approach to reducing the pressure on freshwater from groundwater or surface water is to use desalinated seawater for agricultural activities, particularly irrigation. There has been a discovery that desalinated seawater can be utilized for agricultural purposes, primarily through reverse osmosis technology. Reverse osmosis technology removes all-natural salt present in seawater until it produces unbuffered water that lacks calcium and other important minerals. Initially, reverse osmosis has its limitations due to high costs, high carbon emissions, and a lack of essential minerals needed for agricultural activities, but steps to mitigate these issues have begun to emerge.

For example, Shukla et al. (2022) found a way to reduce the carbon emissions of reverse osmosis technology by powering desalination devices with solar energy. Vanoppen et al. (2018) revealed a concept of assisted reverse electrodialysis (ARED) that dilutes seawater with wastewater stream, which can reduce energy demand and concentration of seawater so that the initial resistance of freshwater sources decline, and thus its investment costs. 

The use of desalinated water has been drawing increasing attention in our quest for new sources of freshwater. In Indonesia, this technology has seen promising results. Using a seawater reverse osmosis (SWRO) plant built by the Indonesian government in 2017, Seribu Islands Regency (Kepulauan Seribu) has successfully desalinated water that has met the quality standard for consumption required by the Ministry of Health and has been applied as a source of drinking water. While local residents are still reluctant to drink the desalinated water due to its high solids content (total dissolved salinity), contextually appropriate technologies such as this merit further investigation in times of climate and water crises.

As an agrarian nation with easy access to marine resources, Indonesia has the potential to explore and implement the use of desalinated seawater for agricultural activities, with the hope of reducing reliance on freshwater sourced from groundwater or surface water.

References:

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2. Martínez-Alvarez, V., Martin-Gorriz, B. and Soto-García, M. (2016) ‘Seawater desalination for crop irrigation — a review of current experiences and revealed key issues’, Desalination, 381, pp. 58–70. doi:10.1016/j.desal.2015.11.032. 

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11. Shukla, A., Agarwal, S. and Narwat, K. (2022) ‘Solar-powered reverse osmosis desalination’, Journal of Physics: Conference Series, 2178(1), p. 012018. doi:10.1088/1742-6596/2178/1/012018. 

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