1999 Volume 44 Issue 1 Pages 1-8
In the Aigamo duck farming system, the effect of weeding depends on the sphere of action of Aigamo ducks. The eating habits of this duck and actions related to their weeding were researched, and the effect of weeding using Aigamo ducks evaluated. A survey of the gullets of the ducks showed a tendency to eat insects as well as weeds. This meant that letting the ducks loose would achieve not only the effect of weeding, but also the extermination of harmful insects. Aigamo ducks were vigorously active early in the morning and at dusk, and moved around freely in the paddy fields. A follow-up survey on one individual duck found the distance covered was 3.8km during the period from 3:00a.m.-20:00p.m. (17 hours) in a 20 a (56m×37m) paddy field. The loose period of ducks were usually settled between 40-50 days, from the end of June (3-4 weeks after transplanting of rice) to the beginning of August (heading date). Thus, the area covered during their active hours was adequate for weed control. P. thunbergii, P. hydropiper and S. juncoides remained in following the Aigamo ducks cultivation, but the weeding they achieved was great and was almost the same as that achieved using an herbicide. Weeds were controlled from a week after the ducks were let loose to the beginning of August.
