By THE NATION
An estimated over 1 billion cubic metres are expected to be used annually.
“The study is supported by National Research Council of Thailand and Thailand Science Research and Innovation,” said Songsak Phatrawutthichai, Department of Irrigation Engineering, Kasetsart University (Kamphaeng Saen Campus). “The study aims to reduce water usage for agriculture in the EEC by at least 15 per cent by adapting growing plans to climate change and study the real water requirement of economic production, especially of durian.”
Songsak added that there are more than 350,000 rai of farmland in the eastern region, most of which are dedicated to growing durian.
“In Rayong alone, there are over 50,000 rai of durian plantations and the number is continually growing every year,” he added. “This study is the first time that academics have tested the belief shared by local farmers for generations that growing durian requires a lot of water to ensure satisfactory results.”
Durian growers in the eastern region use a lot of water in the six months of the growing period starting from November onward.
“In the first three months they use around 150 litres of water per tree per day, and will increase to 200-300 litres per tree per day in the next three months, which is around the time that durian fruits are ready to harvest,” he added. “We tried to reduce the water usage to 100 litres per tree per day in the first three months, and then increase to 200 litres per tree per day in the next three months, and the result was still roughly the same.”
“The reduction of water has no effect on the quality of durian produce,” Somsak concluded.
The study calculated the water needed by durian tree via sap flow equipment that measures the flow of water from the plant’s xylem. Data was collect every day for months to determine what time the plant needed water the most and what time it did not. The experiment was conducted at Patthaphee Plantation in the Muang district of Trad province.
“A 10-rai durian plantation will normally use around 6,573 cubic metres of water in the six months of growing, whereas the method suggested by the study will help reduce water usage to 4,132 cubic metres, which is greater than the target of 15 per cent water reduction,” said Somsak.
“The challenge, however, is to convince local growers to reduce water usage. As durian is a high value economic fruit that requires steep investment, most farmers do not want to risk jeopardising their output by reducing water usage,” added Somsak. “The researchers are also working on integrating the findings to water resource management strategy among local authorities.”