Studies on Integrated Duck-Rice Systems in the Mekong Delta of Vietnam

Abstract

ABSTRACT Two experiments were conducted on smallholdings in the Mekong Delta of Vietnam to evaluate the ability of growing ducklings to control insect pests and weeds in growing, high yielding rice fields. Experiment 1 was carried out in spring-summer 1998 and included four treatments allocated at random to four 360 m2 (4,308 ft2) plots within each of four blocks of a direct-seeded rice field: (Cd) complete application of chemical fertilizers, insecticides and herbicides, without ducks; (CD) no insecticides or herbicides, 50% of the amount of N fertilizer in (Cd), with ducks; (cD) ducks only, without any chemical applications; (cd) no chemicals or ducks. In total, the study included 160 local Tau ducklings, with 20 birds per plot. Two weeks after the introduction of the ducks most of the common species of weed and insect pests affecting rice had been largely eliminated. Rice yields were 4,240, 3,888, 2,176, and 496 kg per ha (1.72, 1.57, 0.88 and 0.20 tons per acre) (P < 0.05) for the Cd, CD, cD, and cd treatments, respectively. Experiment 2 was conducted in the spring-summer cropping season in 2000 and included the same treatments as in Experiment 1, except that the negative control (cd) was omitted. Three weeks after introduction of the ducklings the important weed and insect pests had been eliminated. Rice yields were 3,898, 3,620 and 2,417 kg per ha (1.58, 1.46 and 0.98 tons per acre) (P < 0.001) for the Cd, CD and cD treatments, respectively. The net economic benefits in both experiments were highest for the CD treatment. It was concluded that completely replacing insecticides and herbicides by growing ducks and reducing nitrogen fertilizer application by 50% reduced rice yields by only 7–8% and increased net economic benefits by 10–13%, not including the profits from duck sales, which were USD 0.45 per bird.