How irrigated agriculture can help solve climate change

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Gordon Feller on how climate change is stressing coffee producing water supplies and how irrigated agriculture is a solution worth pursuing. 

In most parts of the Global South where coffee is produced, the impacts of climate change are being felt through changes in water supplies, resulting from increased rainfall variability.

Successive droughts are impacting crop yields in a varied list of countries, including Ethiopia, Kenya, India, and Indonesia.

Professor Dr. Tafadzwanashe Mabhaudhi of the International Water Management Institute (IWMI) and University of KwaZulu-Natal’s School of Agricultural, Earth and Environmental Sciences, says an estimated 70 per cent of land under coffee production belongs to smallholder farmers in climate change hotspots with inherently low adaptive capacity.

Mabhaudhi says access to water for irrigation or supplemental irrigation, is a key “climate adaptation strategy”.

“In many parts of the world where coffee is produced, the major climate risks are water-related, especially decreasing rainfall and increasing incidence and severity of droughts,” he says. “Droughts have become more frequent in Ethiopia and other key coffee growing regions. Access to water for irrigation will ensure that farmers do not lose their crops, enable continued harvests, and help farmers adapt to climate change.”

Ben Faber, an advisor at the University of California Cooperative Extension, specialises in soils, water and subtropical crops, especially those along the subtropical California coast with its Mediterranean climate of winter rain and summer drought. He says water salinity is an obvious sign of water stress.

Faber discovered this early on in field trials when irrigation wasn’t maintained well during the coffee flowering season.

“There were cherries, but where’s the bean? There’s a lot to learn growing coffee in a non-traditional environment. The plants are relatively tough, but susceptible to salt burn (salt damage, tip burn) if they are not irrigated properly. They don’t like heat spells – over 100°C at any time – and they don’t like cold spells – 32°C. They don’t like wind – it dries them out – and during flowering the flowers can dry up. So, they are pretty much confined to growing in a greenhouse in California, or along the coast. They can do well in full sun. But the erratic weather we have had lately has made it more difficult,” Faber says.

“Especially in coastal California, where coffee is most likely to be grown because of the mild climate, the water is often sourced from wells which have salinity issues when high enough. Irrigation is required because of the low rainfall, so applying irrigation water also means applying salts. A grower needs to balance the plant need for water with the need to ensure that the salts from the irrigation water don’t accumulate in the plant root zone and cause toxicity.”

Claudia Ringler, Director, Natural Resources and Resilience at the International Food Policy Research Institute’s (IFPRI) and co-lead of the Nexus Gains Initiative, notes that a few years ago, IFPRI supported Vietnam’s plan to introduce ‘high-efficiency irrigation’ in the country’s highland areas, where much of the coffee in the country is being produced.

“One of the reasons that Vietnam wanted to introduce high-efficiency irrigation was water shortages that could be due to over-expansion of coffee/other crop areas and due to climate extremes (such as drought),” Ringler says.

“All coffee companies procuring coffee from Vietnam have worked on water stress. More extensive adaptations are changes in coffee varieties and moving areas higher up into the mountains. Climate change affects coffee production everywhere in the world, due to heat and water stress, and heat stress is linked to water shortages. However, getting water to the crops does not mean that heat stress can be overcome. It depends on the intensity of the heat.”

Ringler explains that coffee has an ideal growth temperature for day and night, at 23/19°C respectfully for some Arabica varieties.

“If optimal day and night temperatures are substantially exceeded, then coffee plant productivity will decline, regardless if the plant is irrigated or not. Irrigation can slightly lower overall temperatures in the surrounding of irrigation systems, and they can reduce some of the heat stress effects that plants experience. But if the plant is hit with, let’s say, 30°C daytime temperatures, then productivity will go down, and heat-adapted genotypes need to be developed regardless of adequate water supply to coffee plants through irrigation.”

Slow but steady progress using irrigation innovations is highlighted in a report published by the Asian Development Bank: “Quantifying Water and Energy Linkages in Irrigation Experiences From Vietnam”. This research report provides details about the results of a IFPRI pilot study with support from a Vietnam-based consultant, which sought to quantify water and energy use in some of Vietnam’s high-efficiency irrigation systems. The study was linked to an ADB-financed project which provides technical assistance for water efficiency improvements in one of the country’s most drought-affected provinces. In this particular case, high-efficiency irrigation did not seem to be the right solution as water shortages were limited to short periods of time that could be overcome with other water management solutions.

Until this study was conducted, there had been limited information on quantifying energy use in irrigation systems. In the world of plant irrigation, energy is required for ground and surface water pumping, as well as for fueling on-farm irrigation technology and farm machinery.

Solutions for soil sanity

The IWMI continually works with farmers, suppliers and policymakers to understand and adapt to climate-smart agriculture and new sustainable irrigation technologies, such as the introduction of solar pumps; drip irrigation systems, which brings water as close to the roots as possible using emitters; as well as drip lines, sprinklers, and/or sprayers. Solar pumps are particularly urgent given Ethiopia’s recent proposal to end the import of diesel pumps on which many groundwater irrigators currently rely on.

IWMI programs are built on the core idea that there is a need to transition to sustainable irrigation technologies that are water, energy, and food efficient. For example, drip irrigation can be energy efficient and water efficient, as it requires less energy to pump and distribute water. Reducing the wetted area and ensuring water supply to the root zone can minimise unproductive water losses such as soil evaporation and drainage. Depending on the existing systems, such as farrows or sprinklers, a transition to sustainable irrigation technologies could reduce water used for agriculture, and release water to other uses such as environmental flows. However, there is a need for regulation to ensure that water savings are transferred away from agriculture and not used for expanding areas under irrigation.

IWMI’s Mabhaudhi says one such IWMI-led project recommended tax exemption on water-lifting technologies for scaling irrigation in Ethiopia. Ethiopia’s Agricultural Transformation Agency picked up on the idea, and was eventually approved by the government for all agricultural technology. Unfortunately, the policy has faced challenges with implementation.

Mabhaudhi’s research also examines various irrigation technologies which are now being implemented, such as solar-based irrigation, smart water management, irrigation revitalisation and modernisation, and sub-surface and semi-permeable membrane systems.

Solar-powered irrigation systems have been implemented extensively in Asia, with key lessons coming from India. In Africa, the technology is also gaining ground with significant growth in Ethiopia, Ghana and Mali where pilot programs are being conducted. The next steps include scaling and bundling of smart water management with other advisory.

Work on linking irrigation and energy supply is being taken forward by the CGIAR Nexus Gains Initiative where both Ringler and Mabhaudhi are involved in with support to Eastern and southern Africa, and South and Central Asia. While not primarily focusing on coffee, lessons from Nexus Gains’ innovative thinking can be adapted and applied to various contexts, wherever there’s a need to mitigate environmental tradeoffs.

In the coffee context, Nexus Gains is identifying climate smart agriculture practices and clean energy solutions across the coffee value chain, with the potential of solar coffee drying replacing open air drying of coffee beans.

Despite progressive efforts, Mabhaudhi says more holistic solutions are still needed.

“The IWMI is promoting bundled innovations that combine irrigation technologies with other technologies, such as improved varieties, better agronomic practices, access to markets and climate information, and services,” he says. “Bundling innovations assist with developing regionally differentiated and context-specific programs”.

IOT assistance

One of the more modern innovations of smart water management involves planning, developing, distributing, and managing the use of water resources using an array of Internet of Things (IoT) technologies, which is designed to increase transparency, thus making more reasonable and sustainable usage of water resources.

Mabhaudhi says spatial and temporal agricultural water management is critical in irrigated agriculture under water scarcity and climate change to deliver smart water and energy management across multiple scales and users. Possible technologies include soil moisture sensors, such as chameleon soil moisture sensors, remote-sensing and earth-observation, and unmanned aerial vehicles for precision irrigation scheduling and water management.

“These [devices] can be integrated into decision support tools to provide near real-time data for crop-specific irrigation scheduling systems for enhancing water and energy productivity across multiple scales,” Mabhaudhi says. “Given the focus on increasing water scarcity in key coffee growing regions, this is essential.”

Examples of the many IoT applications include monitoring water consumption, checking water levels and quality, detecting chemical leakages, tracking pressure variations along pipes, and use of microcontrollers and sensors, such as ultrasonic sensors, flow sensors, temperature, salinity, conductivity, humidity, pressure, or luminosity sensors. These sensors are placed on pipes or pumps that measure water levels, flow, temperature, and quality of the water in real time.

The sensors transmit message alerts and data over the internet to a cloud server where it is processed, analysed, sometimes with the help of artificial intelligence, and sent to a terminal for the user to consult. The system can control and regulate the usage and quality of water resources, as well as facilitate the maintenance of the default equipment. Such solutions now being implemented in Asian producing regions.

According to the United Nations, global water demand is projected to grow by 55 per cent due to increasing requirements from manufacturing, thermal electricity generation, and domestic use. Thus, while sustainable water access will be key for the future of coffee, it will be equally essential to ensure that precision irrigation techniques are used as the same water is needed for human and planetary health.

This article was first published in the July/August 2023 edition of Global Coffee Report. Read more HERE.

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