Low-cost tools to solve large-scale water problem

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On average, coffee farmers use 60% more water than they need to during the dry season that runs from November to April, across the three to four necessary irrigation rounds, according to research.

Beyond the environmental cost this brings, and the risk water scarcity poses to Vietnam’s coffee industry, farmers also face financial and labour costs. They don’t pay for the water they pump from wells, but must buy petrol to run the pumps, and then spend unnecessary time watering their fields.

Pham Phu Ngoc, the local head of Nestlé’s agri-service team, says that one way to tackle this large-scale water problem quickly is by using low-cost tools that farmers find easy to understand, which they can train their neighbours to use.

In Vietnam, the world’s second-largest coffee producer, 2.6m people rely on the sector for their livelihood. Agriculture in the country’s central highlands, where most of the coffee is grown, accounts for around 96% of the region’s water usage.

But in the coffee fields, everyday objects that are often thrown away are getting a new lease of life, as tools to help farmers save water by scheduling irrigation more effectively. 

Empty condensed milk cans in the fields can be used to measure rainfall. Upturned plastic bottles in the ground can measure soil moisture. These tools are simple to use and cost almost nothing, making it simple to scale-up their use among the nation’s coffee smallholders.

Coffee in Vietnam grows on smallholdings of two to three acres, so large-scale management techniques are hard to implement, but innovative tools inspired by the coffee farmers themselves, show real potential,” Ngoc says.

It’s a concept that Ngoc has helped disseminate among Nestlé’s almost 20,000-strong Farmer Connect network in the country, which supplies the company with coffee directly.

By inserting a plastic bottle upside-down in the soil and observing condensation levels in the bottle, the coffee farmer has an instrument to measure soil water content. When water droplets become scarce, he knows it is time for the first dry season irrigation.

After this irrigation, the farmer can use an empty condensed milk can to show him how much rainwater his trees are receiving—this helps him adjust the amount of water he uses to irrigate throughout the rest of the dry season. 

For example, if a standard milk can is one-sixth full of rain water, he knows his trees nearby have received around 100 litres of water.

The bottle and the can work,” Ngoc says. “It’s more effective than using more complicated tools that could be too scientific for the farmers to master.”

Vietnam’s coffee farmers traditionally used 700-1,000 litres of water per tree for each watering, he explains, but now achieve the same coffee yield using only 300-400 litres – thus, they effect savings of more than 50% in many cases.

While farmers in more developed countries may employ more sophisticated tactics to reduce water use, grassroots activities and education are proving effective in rural Vietnam. The milk can and plastic bottle are good examples of straightforward tools with significant impacts.

The bottle and the can are simple tools to gauge soil moisture content, which tell farmers when it’s the best time to irrigate,” says Carlo Galli, of Nestlé’s water resources team at the company’s head office in Switzerland. “This Vietnam case is not about high tech, it’s mainly about common sense and doing the simple things.”

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