Effects of Nitrogen Application on the Yield and Quality of Later-sown Naked Barley

Abstract

Although the optimal sowing time of naked barley (Hordeum vulgare var. nudum) is mid to late November in Ehime prefecture, it may not be sown whitin that period, depending on the climate and other growing conditions. In this experiment, the effects of nitrogen application on the yield and quality of naked barley sown about 30 days later than the optimal time were investigated. The yield in the later-sown plots was 28% lower than that in the optimal time-sown plot (average of 3 years), due to decreased number of panicles. However, in the plots where the total amount of nitrogen application was increased to 14∼16 g m^-2, decrease in the number of panicles due to later sowing was prevented, and the decrease in yield was only 23%. In later sowing, the number of late emerging panicles due to topdressing at the panicle formation stage, resulting in the deterioration of grain quality (immature grain rate and steely-grain rate was increased and pearled grain whiteness decreased). In order to obtain a higher yield and to prevent deterioration of quality in later sowing, a nitrogen fertilizer should be applied to promote initial growth, and to secure the number of panicles. The suitable nitrogen application rate is 9 g m^-2 for basal dressing, 2 g m^-2 for topdressing at the tiller formation stage is, and 3 g m^-2 for topdressing at the panicle formation stage is.