Effect on Yield of Rice
The rice-duck system enhanced the yield-contributing characteristics of the rice plants, namely, the number of tillers per hill, number of grains per panicle, and average grain weight (Table 1a). Data show that, on the average, the yields of the rice-duck sub-plots are 20% higher than those of the sole rice sub-plots (Table 1b). This echoes similar findings by Ahmed et al. (2004) and Choi Song Yoel et al. (1996). Kang Yang Soon et al. (1995) reported that grain yield (t/ha) was 3% higher in plots with ducks than in sole rice cultivation system. The superiority of the rice-duck system is consistent in all locations and all seasons as can be seen in Table 1a.