Abstract
Single application of fertilizer in nursery box (SAFN) using controlled release fertilizer is becoming widespread as a labor-saving rice cultivation technique in Akita prefecture excluding the northern area. We cultivated cultivar Akitakomachi by SAFN to investigate the relationship between tillering and brown rice quality for three years from 2002 to 2004. The cultivation by SAFN was compared with the conventional cultivation in which readily available fertilizer was applied to the plow layer and topdressing at the meiosis stage. In SAFN cultivation, stem number was smaller, but productive tiller ratio was higher than in the conventional cultivation in all years. Therefore, panicle numbers was almost the same in both cultivation practices. The frequency of tillering from the main stem and at the 5-7th nodal positions was higher than that from other positions in both cultivation practices. In SAFN cultivation, however, the development of primary tillers from the 4th nodal position and its secondary tiller were fewer. In SAFN cultivation, leaf color was better than in the conventional cultivation from the end of June to the end of July, and the exudation rate that indicated the root activity was higher at the ripening period. The average brown rice yield for the three years was 570 g m-2 (this is the yield target of cultivar Akitakomachi in Akita Prefecture) in SAFN cultivation practice. The ratio of whole grain was higher and brown rice protein content was lower than in the conventional cultivation. These results showed that rice cultivar Akitakomachi cultivated by SAFN had a high whole grain ratio and low protein content, because the number of panicles on the main stem and primary tillers at the 5-7th nodal positions was high enough even when rice yield was equal to that in the conventional cultivation practice.
