Effects of the Amount and the Kinds of Fertilizer on the Bleeding Rate and Nitrogen Absorption in a Chinese High-Yielding Cultivar, Yangdao 4

Abstract

Effects of the amount of fertilizer [N, P₂O₅ and K₂O at 0 (Non-F), 6 (L), 12 (M) and 18 g (H) m^-2, respectively], and the kind of fertilizer [conventional fertilizer (CF) and the compound fertilizer containing slow-release fertilizer(SRF, Kumiai-Hifuku Nyoso Iri-Fukugo 444E-80)] on the nitrogen absorption from 23-27 days before heading(EYPF)to heading and bleeding rate from the cut-stem end at meiosis and full heading stages were examined in a Chinese high-yielding indica cultivar, Yangdao 4, in comparison with a Japanese cultivar, Hinohikari. The number of productive stems having four or more leaves per stem increased with increasing amount of applied fertilizer and the ratio of increase was higher in the SRF plot than in the CF plot in both cultivars. The number of productive stems was 1.6-2.3 times higher in Hinohikari than in Yangdao 4 with the same amount of applied fertilizer, while the stem weight was 1.9-2.5 times higher in Yangdao 4 than in Hinohikari. The bleeding rates per hill in CF and SRF plots were higher in Yangdao 4 than in Hinohikari except L-SRF plot at the full heading stage, although it was lower in Yangdao 4 in the Non-F plot. The bleeding rate increased with increasing amount of applied fertilizer in CF and SRF plots in both cultivars, but no significant differences were observed between CF and SRF plots with the same amount of applied fertilizer, and the ratio of increase was higher in Yangdao 4 than in Hinohikari. The average bleeding rate at the both meiosis and full heading stages was closely correlated with the average number of productive stems and the average bleeding rate per stem in Yangdao 4 and the correlation coefficient with the latter was higher than that with the former. In Hinohikari, however, the bleeding rate was closely correlated only with the number of productive stems. The average bleeding rates per hill and per stem were closely related with the amount of nitrogen absorption per hill and per stem during the period 23-27 days before heading, respectively. From the results, it was concluded that Yangdao 4 showed a higher bleeding rate and nitrogen absorption rate per hill than Hinohikari, due to the higher bleeding rate per stem.