Food & Climate
Ganaian Council for Scientific and Industrial Research (CSIR) has launched preparations for new trials aimed at reducing methane emissions from rice production.
Supported by funding from the Climate and Clean Air Coalition hosted by the UN Environment Program, the project focuses on tackling methane emissions, a potent greenhouse gas predominantly emitted during flooded rice cultivation, according to report seen by “Food & Climate”.
By integrating innovative methane reduction technologies, such as alternate wetting and drying (AWD) systems and biochar application among others, the institute aims to mitigate environmental impacts while enhancing agricultural productivity.
Project Lead for the ACE4ES project, Dr. Kwaku Onwona-Hwesofour Asante said: “Reducing methane emissions from rice fields is crucial for sustainable development and climate action in rice producing economies”, according to “B&FT online”.
He added: “Through rigorous experimentation and collaboration with local farmers, we aim to identify practical solutions that balance environmental stewardship with food security”.
Rice fields emit huge amounts of methane into the atmosphere, but alternative means of production could dramatically alter this.
The effect is so powerful that rice production accounts for about 10% of global methane emissions and is responsible for as much as 15% of all emissions in some south-east Asian countries.
For example, in Vietnam, the fifth largest producer in the world, growing rice emits more greenhouse gases than the entire transport sector, according to “DW”.
Rice is a semi-aquatic plant grown in flooded fields under a layer of standing water. This feeds its voracious thirst and suppresses weeds, while also protecting against infections.
Before the advent of synthetic fertilizers, growing rice in floodplains also capitalized on the nutrient-rich sediments washed in by rivers.
But as oxygen levels deplete under that layer of water, microbes that feed on organic matter start emitting vast quantities of the turbocharged greenhouse gas methane —a greenhouse gas vastly more potent than carbon dioxide.
In fact, rice is considered a vital part of nutrition in much of Asia, Latin America, Africa, and the Caribbean, and is estimated to provide more than one-fifth of the calories consumed worldwide by humans, according to “World Economic Forum”.
So, there are many trials seeking solutions. A relatively solution is to drain the fields a few times per season and allow the soil to replenish its oxygen. This suppresses the methane-producing bacteria in the soil, allowing the more climate-friendly bacteria to take over again.
“If you remove the water layer for a few days, methane emissions go down,” said senior scientist at the International Rice Research Institute (IRRI), who is based in Vietnam, Bjoern Ole Sander.
Draining and reflooding the fields three or four times during the growing season can reduce methane emissions by at least 50%, according to Sander.
But this technique doesn’t work during the rainy season of southeast Asia.
“Even if they stop irrigating their fields, there is just a lot of rain, so the fields don’t dry out,” Sander said. “So for those seasons … we need to look for other options.”
Another technique is known as furrow irrigation, in which rice is planted in long rows of dirt mounds and the channels between them are flooded, allowing oxygen into the soil and reducing methane emissions.
The method has become popular in US regions where rice and soy crops are rotated, as it saves labor from deconstructing levees and it conserves water. It has also proven easier to implement in mountainous areas of China, where interconnected farms struggle to use alternate wetting and drying. China is the rice largest producer in the world.
After water management techniques, the most effective strategy is to remove the food the microbes are feeding upon — the leftover straw from the previous harvest.
One way to do this is to burn off the straw, though this has significant air-quality and health impacts. It is far less damaging to physically remove the bulky material that would otherwise be left under the flood water.
Some organizations have been working to incentivize farmers to carry out this laborious task, by finding financially beneficial uses for the material.
Over the past decade, straw balers have sprung up across the Mekong Delta, catering to farmers seeking to sell their straw. It can then be turned into fertilizer for other crops, or used as a growing medium for valuable mushrooms, and can even be turned into a plastic-like material for disposable utensils.