Tu Ky adapts to saltwater intrusion

Farmers in Nguyen Giap commune switch to growing Malabar spinach to reduce the impact of saltwater intrusion.

In recent years, some riverside communes of Tu Ky district have frequently experienced saline intrusion, affecting agricultural production. Faced with this situation, the locality is implementing many solutions to adapt.

Increased salinity

According to the assessment of the Cau Xe - An Tho Construction Management Station, the water level at Cau Xe and An Tho sluices has recently decreased, and the measured salinity has increased. From 2004 to 2019, the salinity at Cau Xe and An Tho sluices was only 0.3-0.4‰, but from 2020 to now, the salinity has increased and the salinity period has lasted longer.

In the winter-spring crop of 2020, the highest salinity measured in these two sluices reached 3.9‰, in 2021 it was 3.8‰, in 2022 it reached 3.3‰ and the peak at the beginning of this year was up to 6.6‰. The number of days affected by salinity has also increased rapidly. If in 2020, the salinity period lasted only 6 days, by the beginning of 2023 it had reached 43 days.

This saline intrusion has significantly affected agricultural production in some localities in the district. In the 2020 winter-spring crop, An Thanh commune had more than 130 hectares of rice on the riverbank seriously affected, with rice yields decreasing by 15-20% compared to previous crops. Ms. Nguyen Thi Ha (in Thanh Ky village, An Thanh commune) said: “My rice is in the tillering stage, when I went to visit the field, I saw that it was gradually withering, the buds were turning black and rotten. At first, I thought the rice was sick, but later I found out that it was infected with salt. That crop, I only harvested a few dozen kilograms of rice. This crop, more than 2 sao of rice on the riverbank also showed signs of slow growth due to slight salinity.”

In Ha Thanh commune, many areas of rice and winter crops have been affected by saline water, reducing productivity and quality. This winter-spring crop, the locality has about 20 hectares of rice affected by salinity, mainly on high fields.

An Thanh Commune Agricultural Service Cooperative has tested planting Tien Hai 1 rice variety and expanded ST25 rice variety to adapt to saltwater intrusion.

Multiple solutions

Faced with erratic weather developments, especially the increasing and prolonged level of saline intrusion, Tu Ky district has proactively guided farmers to find adaptive solutions.

The family of Mrs. Pham Thi Lan (in An Tho village, Nguyen Giap commune) has converted 2 sao of rice to grow Malabar spinach. Mrs. Lan said: "In recent years, the winter-spring crop has often been contaminated with salt, causing a lot of damage from rats, so I decided to switch to growing Malabar spinach. This plant can withstand drought and salt and can be harvested all year round without worrying about rats damaging it."

In recent years, farmers in riverside communes of Tu Ky district have also changed their crop structure to avoid the effects of salinity. Some farmers have switched to growing bananas and fruit trees to limit the effects. In some areas that cannot be converted to other crops, agricultural service cooperatives have proactively introduced new suitable rice varieties into cultivation. According to Mr. Pham Xuan Luan, Director of An Thanh Commune Agricultural Service Cooperative, adaptation is the best solution to deal with salinity intrusion. The cooperative has tested planting about 10 hectares of Tien Hai 1 rice variety. This is a variety that can withstand salinity well and produces quite good quality rice. In addition, the ST25 variety that is being widely cultivated locally has also been encouraged to expand, because this is a variety that can withstand salinity well, has good quality rice, and is suitable for local soil conditions.

Staff of Cau Xe - An Tho Construction Management Station regularly measure salinity at Cau Xe and An Tho sluices to regulate the irrigation system appropriately.

Having dealt with saltwater intrusion for many years, Mr. Nguyen Trong Tai, Director of the Agricultural Service Cooperative of Ha Thanh Commune, said that it is necessary to understand the rules to adapt promptly. Saltwater intrusion usually occurs from around October of the previous year to March or April of the following year. Therefore, it is necessary to pay attention to monitoring the salinity right from the time of taking water to flood the fields. In addition, according to experience, every 3-4 days when hydroelectric reservoirs release water to flood the fields, the salinity in the water decreases, at which time the sluice under the dike can be opened to take water to store in the canal system in the fields.

According to Mr. Nguyen Anh Tuan, Head of the Department of Agriculture and Rural Development of Tu Ky district, to cope with saline intrusion, the district has directed the riverside communes to closely monitor the salinity situation at the sluice gates, and absolutely not take water into the intra-field canal system when the salinity is high. In the long term, the district has a plan to change the crop structure, testing some suitable plant varieties in areas susceptible to salinity. Another solution is to improve the irrigation system by upgrading the sluice under the dike, proposing to renovate the An Tho sluice to regulate water and effectively prevent saline intrusion.

HAI MINH