In the Mekong Delta of Vietnam, salt seawater is increasingly penetrating into inland areas through rivers and ditches and destroying rice harvests. The problem has become a serious threat, and not just for farmers: as the world's second-biggest rice exporter, Vietnam plays a key role in feeding the world population.
Do Thi Hai lives beside her rice paddies. The rice plants rock back and forth likes waves, bending reluctantly to the side as Do Thi Hai steers her wobbly canoe through the paddy. She is now 62 years old and has never seen much more of the world other than her village and the small farms dotting the landscape. Nor does she want to. There's no place she'd rather live than here, in the mighty Mekong Delta, the southern tip of Vietnam. She was born and raised here, she gave birth to her children and buried her husband here, and year for year she harvested the rice for herself and her family here. Until the salt came.
Salt is currently jeopardizing the livelihoods of millions of rice growers throughout the region. Through the vast network of ditches and canals, seawater is advancing further and further inland from the coast and raising the salt content in the water that flows through the rice paddies. It is damaging to rice seedlings, as their roots are unable to develop properly. The leaves turn yellow, the plants wither away and the harvests are spoiled.
In the first half of this year the El Nino phenomenon reached its peak after 100 years. Heat waves, drought and saline intrusion seriously affected agricultural production and lives of local citizens. It is estimated that agricultural losses in the Mekong Delta amounted round about 4.7 trillion Vietnamese dong (210 million U.S. dollars). According to a latest report by the Vietnam’s Ministry of Agricultural and Rural Development, as of June 2016, the shrimp production area which was damaged by saline intrusion covered some 83,000 ha. At the same time, around 232,000 hectares of rice, 6,561 hectares of crops, and over 10,800 hectares of fruit and industrial trees have been damaged.
The farmers are themselves partly to blame for the situation: to procure building material, they deforested the dense mangrove forests over many years and thus removed a natural barrier to the seawater. They also regulated the rivers and ditches in the coastal areas in order to better direct flowing water to their fields. They have long since been unable to grow rice during the dry season. „Until now, however, the monsoon always came in the rainy season and washed the salt water back into the ocean,“ explains Do Thi Hai.
The Seedlings Thrive in Water
Wet rice cultivation is customary in the Mekong Delta. The farmers first grow seedlings in seed fields for one or two months before replanting them in plowed paddy fields. These plots are flooded beforehand with rainwater or river water in order to keep away weeds and pests. Although rice is not a water plant and must therefore be sown in dry fields, the seedlings also flourish in water.
Over the subsequent months, however, the water level must remain constant to ensure that the plants neither dry out nor rot. This cultivation form requires between 3,000 and 5,000 liters of flowing water for one kilogram of rice. Shortly before the harvest (after 90 to 130 days), the farmer drains the field. This enables the grain to ripen to maturity. Some 80 percent of the world's rice crop is produced using this method.
But the situation in the delta has now deteriorated dramatically. Climate change is to blame: the constant sound of rain that has been the soundtrack to the Vietnamese wet season for millennia was nearly silent last year. The meager rainfall was not sufficient to wash the fields clean. And dams now hold back some of the nutrient-rich water that travels down the Mekong. At the same time, the sea level has risen millimeter by millimeter in recent decades, causing the salt water to move further and further inland.
When salinization first appeared during the dry season about two decades ago, the farmers switched to a rotation principle. They continued to plant rice during the monsoon season and flooded their fields with salt water in the dry season so as to breed shrimps on these land parcels. Do Thi Hai tried it as well. „This method safeguarded our income for more than 15 years.“ Yet with the failed rice harvest last season, her shrimp farm is now also threatened. The animals feed on the plant residues in the paddies – and when there is no harvest, there also is not enough natural food for the shrimps.
The farmers in the Mekong Delta need robust and high-yielding rice varieties that can thrive even in very salty water
Bayer's research helps farmers in the delta: during the development of new hybrid rice varieties, the company modifies the seed's properties to meet the specific needs of rice growers. „Farmers in the Mekong Delta need robust, high-yielding rice varieties that can thrive even in very salty water,“ explains Nguyen Thanh Hoan Hao, a seed specialist in Vietnam. Eight years ago, therefore, Bayer developed Arize hybrid. „It's not just less susceptible to disease and higher-yielding, it also tolerates a higher salt content in water far better than conventional varieties.“ Bayer has already saved countless harvests in the delta with such innovative products, says Thanh Hoan Hao. „Many farmers today rely on Arize hybrid rice seed.“
Phan Van Giang also uses this hybrid. The rice grower was one of the first farmers in the delta to switch to the Bayer rice variety eight years ago. „It was definitely the right decision,“ he says. „While my neighbors had to give up their fields due to salinization, I'm still coping quite well financially.“
Before the end of this year, Bayer plans to launch a new hybrid rice variety with even greater salt tolerance in India, Bangladesh and Vietnam. Phan Van Giang is already excited about the new product. „I'll try it out immediately, of course.“
And what are the plans of Phan Van Giang? „I purchased another rice paddy, on which I plan to grow Bayer Arize rice,” says the farmer. He is still optimistic about the future.