Agricultural Sector Accounts for Half of Water Consumption in Brazil, Study Shows

Nthe third episode of the special in celebration of World Water Day , March 22, produced by Rádio USP, the theme is the use of water in Brazil. Every second, the country uses, on average, 2.83 million liters of water, according to data from the National Water and Basic Sanitation Agency (ANA).

The sector that consumes the most water in Brazil is agriculture, just over half, that is, 50.5% of the total volume, compared to other demands, such as human supply with drinking water and use in industry, according to the Report of the ANA Water Resources Situation. This is basically due to irrigation, says professor Tamara Maria Gomes, from the Department of Biosystems Engineering at the Faculty of Animal Science and Food Engineering (FZEA) at USP in Pirassununga.

Irrigation, says Tamara, is used with the main purpose of complementing the rainfall regime in agricultural production. “Although in the world it is only present in 20% of cultivated land, it ends up being responsible for 40% of agricultural harvests, which makes this technique an important instrument to meet the global demand for food, mainly to meet population growth estimated at 10 billion people by 2050.”

This search for an increase in food productivity should also lead to an increase in irrigated areas in the country. “Currently, in Brazil, there are 8.5 million hectares irrigated, which symbolically represents 1/3 of the territory of the State of São Paulo ”, he emphasizes.

For Tamara, the estimates reveal a great potential to increase the irrigated area in Brazil by four times, which would make it possible to quadruple agricultural production without expanding the cultivated areas. “The big challenge is to align the increase in crop productivity with the availability of water in the face of climate events, mainly the increase in water scarcity in certain Brazilian regions.”

In this challenging scenario, to avoid compromising the quality and quantity of water resources, the professor emphasizes the importance of respecting the Water Code and adopting technologies that promote efficiency. “In the case of irrigated agriculture, it is crucial to consider issues such as: soil, climate, plant water demand, terrain relief and topography, water availability and quality, energy availability, factors that will influence the choice of irrigation system.”

Another crucial point to be considered in this context, according to Tamara, is the qualification of the workforce, fundamental to raising the technological level of the system to be used. She also cites as factors that contribute to irrigation efficiency the methods that apply water directly to the root of the plant, reducing evaporation loss, especially in regions with strong winds and/or intense heat. Furthermore, systems that allow the application of fertilizers together with irrigation water, a practice known as fertigation, improve the absorption of nutrients by plants and, in many cases, reduce fuel consumption by agricultural equipment.

Water reuse in agriculture

Water reuse is a very common practice in agriculture and this activity is also regulated by specific legislation. In the agricultural area, reuse materializes through the use of effluents from agro-industrial activities, with sugar cane being the protagonist in this process.

Professor Tamara explains that vinasse is a residual by-product of the sugar and alcohol industry during the production of alcohol. On average, each liter of ethanol produced generates around 12 liters of vinasse. In 2021, in Brazil, 24.8 billion liters of alcohol were produced, resulting in a considerable volume of wastewater in this sector. “This has boosted the use of water reuse in agriculture and, currently, approximately 25% of irrigated areas in Brazil use the fertigation technique with vinasse in sugar cane plantations.” Furthermore, according to Tamara, “projections of future scenarios, worsened by climate change, indicate a significant increase in the practice of water reuse in irrigated agriculture”.