Irrigation and drainage systems and their impact on land use and rice production after renovation (Doi Moi) in the Red River delta of Vietnam - A case study in Tien Son District, Bac Ninh Province

Abstract

In Vietnam, by the renovation starting in 1988 in the agricultural sector, agricultural production system was shifted from the cooperative-base to the farm-household-base and land was allocated to farmers with division of a large-sized parcel to many small-sized plots. Such changes in the agricultural production system have brought about intensification and diversification of cropping in the Red River delta and made improvement and reasonable management of irrigation and drainage systems necessary. A field survey on changes in the irrigation and drainage systems and their impact on the land use and rice production after the renovation was carried out in 1999 in Tien Son District of Bac Ninh Province, located 20 km apart from Hanoi City. Agricultural environment and production, and existing irrigation and drainage systems of Tien Son District were generally described. In the field survey, three communes having different land elevations, from lowest to upper areas, were selected and data was collected at random from 30 farm households in each commune. Situation of irrigation and drainage, rice production and cropping intensity in 1999 were compared with those in 1990. Total area of rice field was unchanged between 1990 and 1999 at the three communes, but percentage of the irrigated to total field was much higher for 1999 than for 1990. Drought-affected and flooded fields were decreased in 1999. Improvement of the irrigation or water condition led to increase in the rice yield of both spring and summer seasons. Irrigated area increased in 1999, but the irrigation methods were not much greatly changed between the two years. In contrast, drainage by pumping machines considerably increased in 1999 at the three communes with a reduction of the flooded area. As a result, cropping intensity increased and more than 2 crops were cultivated in a year in 1999. Impact of the improved situation of irrigation and drainage on the rice production and cropping intensity was most conspicuous for the commune located in the lowest area.