During the Winter-Spring rice crop of 2021-2022 farmers from two communes in Tinh Bien district of An Giang province have been trialing a new technique to address water insecurity problems. The irrigation method, known as the “alternate wet and dry”(AWD) technique has been proposed as a way to save water used and reduce field emissions of greenhouse gases from rice cultivation. The research trial was conducted to determine the suitability of this technique and the potential for future expansion to other areas with similar conditions.
In December 2021, project researchers, local officials, and farmers met to discuss trial design and preparation. During this period, local commune and district officials played an essential role because researchers from Kien Giang and An Giang Universities could not go to the research sites due to Covid pandemic travel restrictions, so there was an unavoidable delay. Four study sites were selected in Van Giao and Vinh Trung communes based on the advice of Agricultural and Rural Development Department staff in Tinh Bien and direct observation of main researchers. These are two communes with ecological and soil conditions suitable for the general requirements of running such a trial.
To be ready for the trial, on January 23, 2022, training was given for farmers participating in the trial who were both women and men of the Khmer and Kinh ethnicity, in an area lying close to the border with Cambodia. Dr Duong Van Nha, Dean of Faculty of Agriculture and Rural Development, Kien Giang University, provided technical guidance to farmers. After training, the group moved to the rice field to set up the experiment so that participating farmers understood clearly how this technique worked on in practice, as well as the theory behind it.
During the trial, the project researchers, local farmers and students of Dept. of Rural Development and Natural Resource Management at An Giang University participated in collecting data on soil structure, biological characteristics and rice yield. The data gathering period was from 20 days after sowing until the plants stopped growing (for the biological data[1]) and harvest time (for water levels and yield components). The time to gather water data was every three days, and biological data was observed every seven days. Monitor water holding capacity start when the field is full of water (the water level was higher than the field surface about 5- 10 cm). To measure the water level every three days to check the reduction of water compared to the field surface (for the experimental areas, the level of water reduction from 3-5 cm depending on the terrain). When the water level was 15- 20 cm below the surface, the next water collection was conducted.
The initial experiment concluded at the end of April 2022. Data (soil texture, water holding capacity, biological characteristics, and yield components) are being analyzed to examine the effectiveness of the trial. The field observation results and feedback from farmer interviews and group discussions (the social component of the study) will be analysed to provide conclusions about the effectiveness of the technique, both socially and agronomically. This will help to build understanding about the benefits (as well as any drawbacks or disadvantages) of the AWD technique for potential replication to other communities both locally in Tinh Bien district and other provinces of the Mekong Delta with similar conditions. It is hoped that this will lead to a gradual reduction in water consumption for agriculture without compromising productivity, therefore allowing the water to be available for other uses downstream, including vital environmental flows.
[1] Total number of shoots per plant, and plant height at different periods of the vegetative stage
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