Effects of organic fertilization and pesticide application on palatability and physicochemical properties of cooked rice

The effects of organic fertilizer (cow and chicken manure) and pesticide on palatability and physicochemical properties of cooked rice (cultivar Nipponbare) were examined for three years from 1996 to 1998 in the paddy field of Okayama University. On the average, the overall eating quality of cooked rice from the plants grown in organic fertilizer-applied & pesticide-free plot and organic fertilizer & herbicide-applied plot were not significantly different from that in the chemical fertilizer & pesticide-applied plot. The palatability in the organic basal fertilizer applied, chemical top-dressed & pesticide-applied plot was inferior to that in the chemical fertilizer & pesticide-applied plot. This suggests that organic fertilization and agricultural chemicals hardly affect the palatability of cooked rice. In 1997, the palatability in each plot without fertilization was superior to that in the corresponding fertilized plot. The overall eating quality was negatively correlated with protein content and hardness/adhesion ratio, and positively correlated with stickiness, maximum viscosity and break down, but not with amylose content. In 1998, the palatability in the organic fertilizer-applied & pesticide-free plot and the chemical fertilizer & pesticide-applied plot without topdressing at the ripening period (amount of total applied nitrogen was equal) was superior to the corresponding plot with topdressing at the ripening period. In order to produce good eating quality rice in organic culture, it is important to restrict the nitrogen absorption of organic fertilizer at the ripening stage.