In Vietnam, ways to reduce the impact of rice on global warming
MISE À DAY
Since he was little, Dong Van Canh has watched the rice paddies of Vietnam's Mekong Delta burn after every harvest, blackening the skies and flooding the air with greenhouse gases.
The cultivation of rice, Asia's staple food, is responsible for around 10% of global emissions of methane, which traps around 80 times more heat than carbon dioxide.
Normally associated with cows, methane is also generated by bacteria that thrive in flooded rice fields and thrive if straw residue is left to rot in the fields after harvest.
The message from the scientists: rice cannot be ignored in the fight to reduce emissions.
Now a rice farmer, Canh, 39, has turned to the production of mushrooms and organic fertilizers with his rice straw, which he no longer lets rot in the fields.
“If we we can sell the straw and make money, all the profit is for us,” he told AFP, running his fingers through a mound of liquid manure that will soon become nutritious food for other crops in the Mekong. .
His transition to cleaner rice cultivation is supported by the International Rice Research Institute (IRRI), a well-established NGO in Asia.
“Everyone here is in favor of this initiative” which aims to recycle straw as an ingredient of nutritious food for other crops, he explains.
Reduce emissions< /strong>
Not new, these initiatives have multiplied over the past two years after a hundred countries pledged to reduce methane emissions by 30% by 2030.
Vietnam, like Indonesia or Bangladesh, is one of the signatories, but not the two biggest producers, India and China.
In Can Tho province, harvest is nearing completion and farmers are pushing small carts overflowing with bales of straw which will then be soaked and spread out to grow mushrooms for sale.
The mixture straw is then transformed into compost, using a machine, before being sold for around 15 cents per kilo.
“In the past, a few farmers did this manually, but it was too labor intensive. We have cut costs in half and will expand to meet market demand,” says Le Dinh Du, local plant protection department manager.
“Rice is having a nice trip . We don't waste anything.”
Reuse rice straw
According to Vietnamese authorities, irrigated rice cultivation has been responsible for almost half of methane emissions in 2019.
The straw reuse technique has been taught “widely to farmers and local agricultural officials” across the country, according to the CGIAR, an international center for agricultural research.
The number of those who actually doing is unclear.
Last year, more than 80% of the rice straw in the Mekong Delta was still burned, according to the World Bank.
According to the researchers, straw management coupled with another method of breaking up the layer of stagnant water in rice paddies to replenish oxygen and reduce bacteria, have “the potential to significantly reduce greenhouse gas emissions. greenhouse”.
In fact, rice, unlike other crops, “has a layer of standing water in the field, which means that there is no exchange of air between the ground and the atmosphere,” says Bjoern Ole Sander, who leads IRRI in Vietnam.
“These bacteria eat organic matter and produce methane.”
According to the Vietnamese authorities, this drying of rice fields has been adopted by a third or a half of the rice land in An Giang province (south) depending on the season, covering more than 200,000 hectares in 2019, twice more than in 2018.
Farmers who have taken the plunge into the Mekong are proud of the way it is grown and of being able to maximize its poten tiel and their income.
At the beginning, “it complicates our life,” says Canh. “But once we figure out how to take advantage of the straw, things are easier.”