Vietnam farmers are reducing methane emissions by changing the way they grow rice. Here’s how

Rice paddies contribute 8% of all human-made methane in the atmosphere, according to a 2023 Food and Agriculture Organisation report. And in Vietnam, rice is considered a gift from the gods. So it was about time that Vietnam, one of the largest exporter of rice in the world,  realise the necessity of reshaping its rice industry.

Vietnam, ahead of both India and Thailand, signed a 2021 pledge to reduce methane emissions at the annual United Nations climate summit in Glasgow, Scotland. Recent research conducted by Vietnam’s Water Resources Science Institute indicates annual industry losses exceeding $400 million. This alarming figure is not only concerning for Vietnam but also for the global community.

A ray of hope and a new technique

Picture the lush green rice fields of Long An province in southern Vietnam’s Mekong Delta—serene, yet bustling with activity. Here, amidst thousands of emerald fields, 60-year-old Vo Van Van’s rice paddies stand out, not entirely flooded like the rest, but nurtured by a novel approach to farming.

That and the giant drone, its wingspan similar to that of an eagle, chuffing high above as it rains organic fertilizer onto the knee-high rice seedlings billowing below.

Using less water and using a drone to fertilize are new techniques that Van is trying and Vietnam hopes will help solve a this major global problem at the heart of growing rice, reported AP.

Van has been working with one of Vietnam’s largest rice exporters, the Loc Troi Group, for the past two years and is using a different method of irrigation known as alternate wetting and drying, or AWD. This requires less water than traditional farming since his paddy fields aren’t continuously submerged. They also produce less methane.

Using the drone to fertilize the crops saves on labour costs. With climate shocks pushing a migration to cities, Van told AP that it’s harder to find people to work the farms. It also ensures precise amounts of fertilizers are applied. Too much fertilizer causes the soil to release Earth-warming nitrogen gases.

Once crops are harvested, Van no longer burns the rice stubble — a major cause of air pollution in Vietnam. Instead, it’s collected by the Loc Troi Group for sale to other companies that use it as livestock feed and for growing straw mushrooms, a popular addition to stir-fries.

Does this new method cut down costs?

Van benefits in various ways. His costs are down while his farm yield is the same. Using organic fertilizer enables him to sell to European markets where customers are willing to pay a premium for organic rice. Best of all, he has time to tend to his own garden.

“I am growing jackfruit and coconut,” he told AP.

Loc Troi Group CEO Nguyen Duy Thuan told AP that those methods enable farmers to use 40% less rice seed and 30% less water. Costs for pesticides, fertilizer and labour also are lower. Thuan said Loc Troi — which exports to more than 40 countries including in Europe, Africa, the United States and Japan — is working with farmers to expand acreage using its methods from the current 100 hectares to 300,000 hectares.

That’s a long way from Vietnam’s own target of growing “high quality, low emission rice” on 1 million hectares of farmland, an area more than six times the size of London, by 2030. Vietnamese officials estimate that would reduce production costs by a fifth and increase farmers’ profits by more than $600 million, according to the state media outlet Vietnam News.

How does rice cultivation produce green-house gases?

In contrast to other grains, rice is a semi-aquatic plant cultivated in flooded fields, where it thrives under a layer of stagnant water. This method not only satisfies its substantial water needs and prevents weed growth but also provides protection against diseases. Before synthetic fertilizers became prevalent, growing rice in floodplains took advantage of the nutrient-rich sediments deposited by rivers.

However, the oxygen-depleted environment beneath the water layer prompts microbes to produce significant amounts of methane, a potent greenhouse gas even more impactful than carbon dioxide.

This phenomenon contributes significantly to global methane emissions, with rice production alone accounting for approximately 10% of these emissions worldwide. In some Southeast Asian nations, like Vietnam, rice cultivation contributes up to 15% of total emissions, surpassing those from the entire transportation sector.

Addressing the practices within the rice industry could be pivotal for certain countries to fulfill their commitments under the Paris Agreement and mitigate climate change, reports Deutsche Welle (DW).

What additional methods can farmers employ to decrease methane emissions?

Another approach involves utilising furrow irrigation, where rice is planted in elongated rows of soil mounds with flooded channels between them. This method introduces oxygen into the soil, thereby reducing methane emissions.

This technique has gained popularity in regions of the United States where rice and soy crops are rotated due to its labour-saving aspect of avoiding levee deconstruction and its water conservation benefits. Moreover, it has proven easier to implement in mountainous areas of China, where interconnected farms find it challenging to adopt alternate wetting and drying practices.

Following water management strategies, the next most effective method is to eliminate the microbial food source, which includes leftover straw from previous harvests.

One approach is to burn the straw, although this poses significant air quality and health concerns. Alternatively, it is less harmful to physically remove the bulky material that would otherwise remain submerged under floodwater.

Efforts by organisations like the International Rice Research Institute (IRRI) aim to encourage farmers to undertake this labour-intensive task by identifying financially rewarding uses for the straw.

In recent years, straw balers have become prevalent across the Mekong Delta, catering to farmers interested in selling their straw. This straw can then be repurposed as fertilizer for other crops, utilised as a growing medium for valuable mushrooms, or transformed into a plastic-like material for disposable utensils.

The World Bank is championing Vietnam’s endeavors, recognising methane mitigation as a cost-effective strategy.

With inputs from agencies

This article has been republished from The Firstpost.