(16(2):22-34)肥料分施對水稻產量，產量構成因素，及其他農藝性狀之效果(四)

The effects of time of fertilizer application on yield, components of yield, and some important agronomic characters of rice evaluated in 1965 at the Chiayi Agricultural Experiment Station are summarized. Treatment C with nitrogen fertilizer top-dressed at maximum tillering stage and treatment F, at both maximum tillering and panicle initation stages produced the highest yields in both crops. The yield increases appeared to be due largely to the increase of panicles per hill. Top-dressings of nitrogen fertilizer before maximum tillering stage did not contribute to yield increase. The effects of applying nitrogen fertilizer at heading stage and split application of potassium fertilizer were not evident in this experiment. Early application of nitrogen fertilizer generally produced more tillers per hill and larger leaf area index in the first crop whereas late application of nitrogen fertilizer resulted in better growth of rice plant in the second crop. There was an indication for a tall and late heading plant to be associated with high yielding ability. Significant interactions between treatments and years were observed in panicle length and number of grains per panicle in the first crop, and grain yield and number of panicles per hill in the second one. 本文係報告嘉義農業試驗分所於民國54年第1期作起至民國55年第2期作承辦全省性水稻肥料分施試驗之綜合結果。 在水稻合蘗盛期施用氮肥1次之處理3及在分蘗盛期及幼穗分化期各施用1次氮肥之處理6，其產量在第1、2期作均較其他處理為高，其增產原因為每株穗數之增加。在分蘗盛期前之追施氮肥，效果甚微。又在齊穗期之氮素追肥及鉀肥之分施，在本試驗亦未見成效。 在第1期作早施氮肥能增加每株分蘗及葉面積指數，而在第2期作，則以後期追施氮肥之稻株發育較佳。稻株高，而生育日數長之處理，似較高產。 第1期作之穗長與每穗粒數，其處理與年份之交感作用達顯著水準，而第2期作之產量及每株穗數之交感亦極顯著。餘外性狀，均未見有顯著交感作用之存在