Effect of chitin application on growth and yield of rice

Field experiments were carried out in 1994, 1995, and 1996 to study the eff ects of chitin on the growth and yield of rice. The results of experiments in 1994 and 1996 showed that chitin as a basal dressing increased the grain weight, and no difference was noted in the grain weight between chitin 500 g m-a applied plot and the fertilizer plot. In 1995, since rice leaves in the chitin 500 g m(-2) applied plot and the fertilizer plot were infested b y Cnapharocrosis medinalis GUENEE, no difference in grain weight was noted between all chitin-applied plots and the fertilizer plot. positive correlat ions were observed between the number of spikelets per m(2) and the grain w eight. The percentage of ripened grains was about 90% in the nonfertilizer and all chitin-applied plots, whereas the fertilizer plot was low. This res ult may be considered as follows. In the fertilizer plot, LAI at the whole growth stage was high, and light extinction coefficient (K) was increased a fter heading time. As a result, CGR was decreased. On the other hand, the m aximum LAI in the chitin 500 g m-a plot was about 4.5, light extinction coe fficient after heading time was low, and CGR was high. As in the results, g rain weight in the chitin 500 g m(-2) plot was at the same level as the fer tilizer plot.