• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.473-478
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• 2003

This study was conducted to clarify the effects of duck free-ranging time on the growth and behavior patterns of duck, pH and dissolved oxygen of irrigation water, and growth and yield of the rice plants in paddy fields. Two paddy fields with each 5 aye were used for 12 hours duck free-ranging plot (12HFR) and 24 hours duck free-ranging plot(24HFR). Body weight gain of the duck was not different between 12HFR and 24HFR. Eating and feather grooming behavior in the 12HFR were significantly longer than those of 24HFR, but other behavior patterns were not so. Working behavior and activities of duck in paddy fields tended to be longer in the 12HFR than in 24HFR. However, any difference was not found on staying time of duck in paddy fields. Although it was not statistically significant, pH and dissolved oxygen of irrigation water tended to be higher in the 12HFR than in 24HFR. The plant height of rice in the 12HFR was significantly shorter than that of 24HFR during the latter half period. The number of tillers per hill was significantly increased in the 24HFR than in 12HFR. The shoot dry weight of rice in the 12HFR was significantly less than in the 24HFR during the heading stage of rice plant, but the root dry weight was not different. The number of spikelets per panicle was significantly less in the 12HFR than in 24HFR, however the percentage of ripened grains was significantly higher in the 12HFR. The yield of rice was not significantly different between the treatments. In conclusion, the free-ranging time of duck for 12 hours in paddy fields promoted eating and working behavior of the ducks. Free-ranging time did give effects on rice traits such as the number of tillers per hill, plant height, shoot dry weight of the rice plant, and spikelet number and percentage of ripened grain. However, the duck growth, pH and dissolved oxygen of irrigation water, and paddy rice yield were not affected by duck free-ranging time. These results might suggest that almost same effect as in 24 hours of free-ranging can be obtained with only 12 hours of free-ranging in daytime.