ASARECA debuts Chameleon sensors as Uganda moves to support sustainable water use

November 6, 2024 in Land & Agriculture, Science and Technology by Editor

Michael Wakabi

“The sensors are a decision-support tool designed to help farmers determine when and how much water they need for irrigation, as well as to understand how much nutrient loss occurs due to leaching from over-irrigation,” says Dr. Joshua Okonya, Program Officer for Technology and Innovation at ASARECA.

It is only natural for irrigation-dependent farmers to water their crops at every available opportunity. While this may provide individual farmers with a sense of security, scientists warn that it can be wasteful, as it often leads to over-watering. This not only consumes more water than necessary but also increases the risk of nutrient loss through leaching.

Now, as chameleon soil moisture and nutrient sensors make their debut in Uganda, scientists and policymakers hope their simplified user interface will encourage rapid adoption and efficient water use. Farmers in Kasese, western Uganda, also expect that the sensors will help ease emerging tensions over water sharing.

The introduction of chameleon sensors in Uganda—so-called because they display scientific information using a range of colours rather than traditional numerical displays—is being championed by the Association for Strengthening Agricultural Research in Eastern and Central Africa (ASARECA).

According to Dr. Joshua Okonya, the Program Officer for Technology and Innovation at ASARECA; the sensors are “a decision-support tool designed to help farmers determine when and how much water they need for irrigation, as well as to understand how much nutrient loss occurs due to leaching from over-irrigation.”

The array of tools—including Chameleon field readers, wetting front detectors, Chameleon EC meters, and Chameleon nitrate strips—work together to help farmers assess soil moisture, saturation, and nitrate levels.

These tools assist farmers in deciding when to start and stop irrigation or when to apply fertilizers. They were introduced during a training session for model farmers, who will serve as trainers in sustainable soil moisture management for efficient water use.

The chameleon sensors, featuring two types of readers, are equipped with arrays buried at depths of 15, 30, and 45 centimetres to measure soil moisture levels corresponding to the root zones of different crops. The reader display uses color codes to indicate moisture levels: blue for adequate moisture, green for moderate moisture, and red for insufficient moisture. A simplified card reader, costing USD 20, shows only the color codes, while a more advanced Wi-Fi-enabled reader, priced at USD 148, can log and transmit soil moisture data over extended periods. This advanced reader also displays soil temperature readings alongside the color-coded moisture information.

The Wetting Front Detector is buried in the soil and it is automatically triggered to indicate that the soil is flooded. A farmer can then stop irrigation. A water sample collected from its funnel can be tested to show levels of leaching by indicating salinity and other nitrates in the soil.

Farmers can use that information to decide how to manage fertiliser application and when to take measures to mitigate salinity in the soil.

According to Dr. Okonya, high salinity in the soil impairs plants capacity to absorb moisture and nutrients while leaching washes away essential nutrients. Both conditions result in wilting and death of the plant.

Dr. Isaac Fandika, the Chief Agricultural Scientist in Malawi’s Department of Agricultural Research Services, led a five-day training-of-trainers workshop for model farmers and extension workers in Kasese from October 21-25. He emphasized that the Chameleon sensors are a crucial intervention for promoting efficient water use.

Previously, scientists have had problems communicating with farmers on how to use scientific tools. But that changed after colours were used to replace numerical information.

By relaying complex scientific information through simple color codes, the sensors also enhance communication between scientists and farmers, making it easier for farmers to understand and act on soil moisture data.

These technologies are easy to use because they use colours,” explains Dr. Fandika. “When it’s green, it shows moderate moisture; red indicates no moisture, and blue shows adequate moisture. This allows farmers to easily decide when and how much to irrigate. It saves water and time—time that can be used for other tasks and water that can be shared with other farmers or used for additional crops. In Malawi, it has helped reduce conflicts over water within irrigation schemes.”

The tools were developed by VIA and have been piloted in Malawi and Tanzania among other countries.

“These moisture-measuring tools are climate-smart, helping farmers decide how much and when to irrigate. Many governments across Africa, including Uganda, are promoting irrigation to help farmers adapt to the impacts of climate change by managing water more efficiently,” says Dr Dr. Fandika who also doubles as Virtual Irrigation Academy (VIA) Coordinator for Malawi.

“We believe that if farmers in Uganda adopt this technology, it will help them improve production with limited water resources, despite the impacts of climate change. This will boost productivity and enhance climate change adaptation,” he adds.

With multiple rivers flowing from the vast Rwenzori Mountain catchments on their way to Lake George, Kasese District may not initially appear to be a water-stressed area. However, as climate-induced dry spells become more frequent and prolonged, tensions over water usage are emerging among farming communities.

The 2,000-hectare Mubuku 1 and 2 Irrigation Scheme is home to 377 farmers. Only about half of this land is irrigated using water from the Sebwe and Nyamwamba rivers. The farmers employ a furrow irrigation system, where one field is flooded before allowing the water to flow downstream to other users.

According to officials, the available water should be adequate. However, tensions arise from anxiety over water security, prompting some farmers to block the flow of water to downstream users.

“We are seeing conflict, not due to an actual water shortage but rather the perception that the water is insufficient. Additionally, farmers want to water their crops every two or three days, even when it may not be necessary. We hope these technologies will help farmers know when to irrigate, thereby reducing conflict over water,” says Mr. Julius Baluku, the District Production Officer for Kasese District.

Baluku adds that a misunderstanding of proper irrigation practices has contributed to conflicts over water usage in some schemes and even corruption in water allocation.

“These tools will help farmers, especially those in micro-irrigation schemes, to monitor and determine which field needs water at any given time,” he says.

According to Titus Namanya, a water engineer working with Uganda’s Ministry of Agriculture Animal Industry and Fisheries, the training of model farmers is intended to skill them in efficient application of water resources for agriculture. The project is also intended to create synergies between the public and private sectors in creating sustainable pathways for climate-smart tools to reach user communities.

“Water resources are declining and under stress globally. Kasese is also a water scarce area. We expect that targeted water usage will also help us track changes in output that cab be attributed to this intervention,” he said.

With funding from Australia, ASARECA coordinated research in Malawi and Tanzania to validate the applicability of the tools. After seeing that they have worked well in Malawi and Southern Africa, ASARECA is now coordinating their proliferation in Uganda and other African countries.

In Malawi and Tanzania, farmers registered a 50pc reduction in water usage and other inputs such as time and fertilisers. A corresponding 50pc reduction in the cost of pumping and time spent irrigating resulted in improved margins for farmers. Yields also increased by 10-20pc among farmers who used the tools. Time saved freed farmers to engage in leisure activities, while conflict subsided and social cohesion improved within the irrigation schemes.

Baluku hopes similar benefits will be registered in Kasese.

“We also have other smaller irrigations schemes that we have established as a district,” he says. “But one thing we have discovered is that water rationing is difficult because it is little water being competed for by many farmers. Scheduling it becomes very difficult. We have also seen cases in some schemes where the leaders don’t exercise fairness in water allocation and there’s some element of corruption where water is given to those who have given the scheme head some inducement. This generates a lot of conflict.”

He believed having precise information about soil moisture levels will reduce anxiety and the incentive among farmers to hoard water.

“Being able to know how much water to allocate to the crops and when to irrigate will help us in solving some of these conflicts because water scheduling will be properly guided basing on the requirements in the gardens. Farmers will get water equitably, it will also enhance production and once productivity increases, our people will earn more. This will lift them from the subsistence to money economy,” he adds.

Kabasinguzi Jessica, a farmer and extension worker in Kasese says the training of trainers addresses two major issues. Farmers knowledge of water management will get better and getting farmers to train farmers will address a critical manpower gap in extension services in the district.

“Training lead farmers will facilitate farmer to farmer knowledge transfer. But it is also true that we have been wasting a lot of water here because we just irrigate to see that the water is flooding without putting in mind how much is really needed. This system is very useful because when you see the amount of water and nutrients we have been losing, it is significant,” she says.

“I expect to see a high adoption rate for these tools because they are essential for the many farmers who running small irrigation schemes of their own,” she adds.