An ensuring sufficient yield and high-quality farming system
2007
Okabe, M. | Baba, T. | Yokoto, K. | Suyama, K., Tokyo Univ. of Agriculture, Tokyo (Japan)
The rice-duck farming system is an organic agriculture system carried out by about 10,000 rice farmers in Japan. In this system, rice ducks are left in a paddy field for about 2 months(beginning 2 weeks after transplanting to several days before heading). Rice-ducks are effective in weed and insect pest control resulting in a stable yield without the need for using herbicides and insecticides. One of the fluctuating elements of the system is that the rice tends to have a high protein content and a low palatibility compared with commonly cultivated rice. It is possible for rice-ducks feces to stimulate nitrogen absorption of rice plants and affect the palatibility of rice. In this study, the role of rice-duck feces was clarified as a nitrogen source and examined suitable fertilization methods for high-quality rice production in the rice-duck farming system. Inverse correlation was observed between palatibility and soil nitrogen content at harvest. This suggests that the supply of feces from rice-ducks increase soil nitrogen and cause low rice palatibility. Standard application of basal fertilizer with rice-ducks left excess nitrogen in the soil. Since loss nitrogen by denitrification was limited in the paddy field during following(from winter to spring), residual nitrogen was available for rice production the following year. A sufficient yield and a high quality of rice in the rice duck farming system was obtained using a standard bi-annual of basal fertilizer.
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