Odor and Irrigation Water contamination by Duck-Rice System and its Effect in Weed Control, Rice Growth and Yield

Summary

This study aimed to find out the odor and irrigation contamination by duck-rice farming systems and its weed control, rice growth and yield under the system with hairy vetch cultivation. Rice yield was reached at 4.1t/ha in the plot of duck-rice + hairy vetch cultivation while the plot of duck-rice achieved only 3.9t/ha. The nitrate nitrogen concentration in irrigated water ranged between 0.17 and 0.37ppm and did not show much difference among the treatments until the end of June, but the maximum difference detected was in the duck-rice plot in July, 0.11ppm, compared to the hairy plot and duck-rice + hairy vetch plot, 0.08ppm and 0.09ppm respectively. But the concentration of ammonium nitrogen at the end of July reached 4.07ppm in the plot of duck-rice, but it was 2.83ppm in the plot of duck-rice + hairy vetch and 2.12ppm in the hairy vetch plot respectively. The bio-mass of weed showed the lowest in the plot of duck rice + hairy vetch and highest in hairy vetch plot among the treatments. The plot of duck-rice shows the water contamination in terms of nitrate and ammonium nitrogen in the irrigation outlet and strong odor of duck dung even in the neighboring or surrounding field were detected due to high number of ducks introduced in the duck-rice system, 300 ducklings/ha. Therefore, it is strongly recommended to reduce the number of ducks introduced to the rice field. It was concluded that cultivation of hairy vetch in the duck-rice system is necessary because it shows not only the positive environmental impact such as irrigation water and insect habitats, but also the rice growth and yield.