Water balance assessment in watershed and irrigation block scale for improvement of water use efficiency in paddy fields : A case study of the Pursat river basin, Cambodia

概要

Population growth and rising incomes and urbanization are increasing demand for water. Moreover, increasing agricultural production is needed for food security. Since agriculture consumes the majority of water among other sectors, its increase will put greater pressure on the competition for water. As the balance between water demand and water availability has reached critical levels in many regions of the world, a sustainable approach to water resource management in, agriculture and minimize non-beneficial water losses is essential. In Cambodia, water resources is highly variable due to unpredictable rainfall and uncertainty of duration of the dry season, making a big challenge for especially rice production while it has increased significantly in ·the last decades. Therefore, with the aims of improving agricultural water use efficiency for increasing rice production in Pursat River Basin, three main works were carried out in this research:

• Analysis of water balance in irrigation districts of a river basin of Cambodia, namely Pursat, to evaluate the current condition between water availability of the river and irrigation water demand

• Assessment of discharge process in the river basin to understand the seasonal
variation of the river flow especially low flow in the dry season

• Evaluation of an知tificial Ca])illary Barrier (CB) system in a soil column experiment for optimization of crop water use efficiency under different
irrigation management scenarios.