Restoring rice production affected by water shortage and salinity.

Việt Nam•14/06/2024

Over 142 hectares of summer-autumn rice crops in Hoa Phong, Hoa Nhon, and Hoa Tien communes (Hoa Vang district) and Hoa Tho Tay ward (Cam Le district) have been affected by saltwater intrusion into the water sources at pumping stations. Authorities are actively coordinating with local farmers to address the saltwater intrusion, water shortage, and restore production in severely damaged fields.

Da Nang Irrigation Exploitation Company Limited is maintaining the operation of drought-relief pumping stations to increase water supply to rice fields. Photo: HOANG HIEP

Farmers suffered heavy losses.

The Tuy Loan pumping station (Hoa Nhon commune, Hoa Vang district) ceased operation from May 30th to the afternoon of June 10th due to severe salinity contamination of the Tuy Loan River, directly affecting large areas of summer-autumn rice crops in Hoa Nhon commune. The Da Nang Water Resources Exploitation Company Limited coordinated water resources from pumping stations, diverting saltwater intrusion to pump water, building temporary dams, and installing additional pumping stations to combat drought. However, up to 40 hectares of rice in Hoa Khuong Dong, Hoa Khuong Tay, Thach Nham Tay, Phu Hoa 1 villages, and a small area in Phuoc Thai village (the Dua field) lacked sufficient irrigation water. Additionally, 26 hectares of rice in Hoa Tho Tay ward (Cam Le district), irrigated by the Tuy Loan pumping station, were also affected by severe salinity contamination of the Tuy Loan River upstream of the Giang Bridge during those 11 days.

In recent days, hydropower reservoir owners in the Vu Gia River basin have released water downstream at a higher flow rate than before. Combined with thunderstorms and low tides, this has reduced the salinity of the river water at the pumping stations. At 5 PM on June 10th, immediately after monitoring the salinity of the Tuy Loan River upstream of the Giang Bridge and finding it had dropped below 1.2 ppt (1.2‰), the Da Nang Water Resources Exploitation Company Limited immediately put into operation four pumps after 11 days of inactivity. This water was then channeled to Truong Loan Reservoir to mix with the reservoir water, further reducing salinity and providing a water source for the Truong Loan pumping station to irrigate the rice fields. Mr. Phan Thanh Tong, Head of the Tuy Loan pumping station (Da Nang Water Resources Exploitation Company Limited), said: “We continuously monitor the salinity of the river water to avoid pumping water with excessively high salinity. Currently, we prioritize supplying water to the Dua rice field (Phuoc Thai hamlet) and the Gia Tria rice field (Thach Nham Tay hamlet), other rice fields in Hoa Nhon commune, and rice fields in groups 5, 6, and 7 of Hoa Tho Tay ward.”

According to observations on the morning of June 12th, in the fields of Hoa Khuong Tay village (Hoa Nhon commune), many rice paddies had been irrigated from the Tuy Loan pumping station, but many others were still dry, with cracks visible on the surface. Ms. Le Thi Thu Hoa (a farmer from Hoa Khuong Tay village) said: “My family sowed 2.3 acres, but due to the irrigation water being contaminated with salt and then drying up for many days, more than 50% of the rice died. The remaining rice is surviving thanks to the rain. Now that water has returned, people are replanting, adding fertilizer... to help the rice plants recover and grow quickly, but we also hope that the relevant authorities will have solutions to ensure irrigation water so that people can harvest and minimize losses.”

In Hoa Tho Tay ward, water pumped from the Tuy Loan pumping station has flowed into the rice fields, but due to salinity and prolonged drought, many fields have a rice mortality rate of 80-90%. Seeing the water arrive, many farmers are taking advantage of the opportunity to flush out the salt to save the surviving rice and replant. Mr. Vo Hai (a farmer in group 5, Hoa Tho Tay ward) said: “My family’s 2.13 sao (approximately 2,130 square meters) of rice fields have a mortality rate of 80-90% due to salinity and drought, resulting in a loss of nearly 1.5 million VND in seeds, fertilizer, plows, and threshing equipment. People hope that the authorities will provide compensation for the losses if they cannot replant due to the delayed planting schedule, or if they are allowed to replant, they hope for support in terms of seeds, plowing equipment rental costs, etc.”

Residents of Hoa Tho Tay ward (Cam Le district) are taking advantage of the time to replant rice seedlings. Photo: HOANG HIEP

Rinse off the salt 1-2 times, then care for the plants or replant.

In Hoa Tien commune (Hoa Vang district), Da Nang Water Resources Exploitation Company Limited has implemented various solutions to combat drought and ensure irrigation water for 135 hectares of summer-autumn rice crops within the irrigation area of the Duong Son and Mieu Ong pumping stations. Simultaneously, water from Dong Nghe reservoir has been supplemented to mix with water from some pumping stations affected by salinity, creating a water source for drought-relief pumping stations in Hoa Phong commune (Hoa Vang district). Mr. Nguyen Sy, Director of Hoa Phong 1 Agricultural Production Service Cooperative, said that currently, the salinity at pumping stations along the Yen River downstream of the An Trach dam has decreased, allowing them to resume operation. This, combined with water from drought-relief pumping stations installed by local authorities and farmers, ensures irrigation water for rice crops, washes away salinity, reduces salinity in the fields, and restores production. To date, 43 hectares of affected rice fields have had their water shortage and salinity issues resolved, including 9 hectares that required replanting. Currently, the newly replanted rice is growing weakly, so farmers are actively monitoring and caring for it.

According to the Sub-Department of Agriculture (Department of Agriculture and Rural Development), the unit has guided cooperatives and localities on solutions to overcome the problems of saline intrusion and water shortage in the summer-autumn rice crop, especially in areas with high rice mortality rates. Accordingly, for areas with 30-100% rice mortality due to salinity, cooperatives and localities should encourage farmers to replant. Before replanting, flood the fields with fresh water and then drain it to wash away the salt 1-2 times. Only when the salinity level is checked and found to be safe (below 1‰) should replant with short-day rice varieties and ensure adherence to the planting schedule. For areas with less than 30% rice mortality due to salinity, flood the fields with fresh water, then drain and wash away the salt 1-2 times, combined with foliar fertilization to promote rice growth and development, then replant and care for the crop as usual. The unit also requested the Da Nang Irrigation Exploitation Company Limited and the cooperatives to continue monitoring the salinity of water sources at pumping stations before irrigating rice crops and to ensure adequate irrigation water. For newly sown rice fields or those in the replanting stage, the unit recommends ensuring the salinity of irrigation water is below 1‰. For rice fields in the rooting, tillering, and greening stages, it is recommended to irrigate with water with a salinity below 2‰.

HOANG HIEP

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