Abstract
One of the major constraints of agricultural development in the Red river delta is inadequate control of water conditions. The present study aims to clarify the water conditions of agricultural land, analyze their impact on production and labor input, and estimate the effect of the improvement of water control, with emphasis on rice cultivation. Water conditions of agricultural land are closely related to microtopography. Yield and labor input of rice cultivation in the higher and lower areas are affected by insufficient irrigation water supply and inundation, respectively, both in the spring and summer cropping seasons. However, high labor input enables farmers to adopt similar cropping patterns and rice varieties over the whole area, regardless of variation in water conditions. Irrigation and drainage improvement combined with land consolidation are recommended to increase rice yield and reduce labor input, by which 40% to 150% yield increase and 30% to 60% labor saving are expected.
