We studied the effects of applying improved water management technology during the wet season in canalirrigated ricefields for 6 yr (1989-94) in the Jian minor canal of the Tirhut main canal in Gandak command, Bihar, India. We irrigated rice to a depth of 7 cm 3 d after ponded water disappeared. This treatment was compared with the usual farmers’ practice of irrigating according to the availability of water from canals and rain. Farmers generally apply more than 10 cm irrigation water continuously, especially in the head of the minor canal. Six to 18 farms were used in the study each year, with an average field size of 0.4 ha (see table). Soil was silty loam. A stage level recorder at the opening of the minor canal and Parshall flume in each outlet were used to measure irrigation water used.