羅正宗、莊志慶。2016。水稻氮素利用效率之研究(I) 氮素施用量對水稻氮素利用效率及其組成分之影響。 臺南區農業改良場研究彙報67：1-12。
本研究藉由不同氮肥施用量探討水稻各生育時期之植株氮素分配、對氮素利用效率及其構成因素之表現。由結果顯示：水稻植體之總氮素含量隨氮肥施用量之增加而增加，提高氮肥施用量相對增加植株總氮素吸收量，總乾物重也上升。第一期作及第二期作兩參試品種在不同氮肥處理下，其氮素利用效率及吸收效率皆呈現隨氮肥施用量之增加而減少的趨勢，且第一期作之氮素利用效率高於第二期作；氮素吸收效率則呈第二期作高於第一期作。臺?9號之氮素利用效率及吸收效率比臺?8 號有較高之表現。第一期作兩品種氮素應用效率皆以每公頃200 公斤氮素處理最低，第二期作臺?8 號之氮素應用效率則隨氮肥用量之增加而減少。第一期作稻株在抽穗期之前所累積於莖、葉的氮素，於榖粒充實期間轉移至榖粒之比例隨氮肥施用量之增加而減少，而第二期作則相反，隨氮肥用量之增加而增加，且第二期作明顯高於第一期作；由此結果亦發現第二期作穀粒充實期間所累積之氮素量與收穫期榖粒氮素總量的比值較第一期作為高，此為追求高品質水稻栽培過程值得注意的問題。
Studies on Nitrogen Use Efficiency of Rice (I)
Effects of Nitrogen Application Rates on Nitrogen Use Efficiency and its Components of Rice
Lo, J. C. and C. C. Chuang
Various nitrogen application rates were used to investigate the distribution of nitrogen on plant during growth periods, nitrogen use efficiency and its components of rice yield. The results indicated that the total nitrogen contents of rice plants increased along with the increase of nitrogen application rates. When the nitrogen application rate was raised, the nitrogen absorbing ability was relatively raised. Under various nitrogen fertilizer treatments, the nitrogen use efficiency and nitrogen uptake efficiency were decreased along with the increase of nitrogen application rate in the first and second crops of TK 8 and TK 9. The nitrogen use efficiency of the first crop was higher than that of the second crop but the nitrogen uptake efficiency of the second crop was higher than that of the first crop. The nitrogen use efficiency and nitrogen uptake efficiency of TK 9 were both higher than those of TK 8. The nitrogen use efficiency of two varieties in the first crop were the lowest under 200 kg/ha nitrogen treatment. The nitrogen use efficiency of TK8 decreased with the increase of nitrogen application rate in the second crop. The ratio of the accumulated nitrogen in the stems and leaves before heading date of the plants in the first crop and the nitrogen transferred to grain in the grain filling period decreased along with the increase of nitrogen application rate. However, it was increased along with the increase of nitrogen application rate in the second crop. In addition, the ratio of nitrogen transferred in the second crop was obviously higher than that of the first crop. Based on the results, the ratio between the total nitrogen amounts of the harvesting period and the accumulated nitrogen contents in the grain filling period of the second crop was higher than that of the first crop. This is a critical and crucial point in the procedure of looking for high quality rice cultivation.
What is already known on this subject?
Nitrogen is the important factor on plant growth, grain yield and grain quality of rice. There were less study focusing on the relationship between nitrogen use efficiency and its components in Taiwan.
What are the new findings?
This is the first report on nitrogen use efficiency and its components of rice in Taiwan.
What is the expected impact on this field?
According to this finding, it can be served as a valuable reference for rice breeding and culture management in the future. The farmer’s profit can be increased by reducing input during rice cultivation.
Key words: Rice, Nitrogen Use Efficiency, Nitrogen
Uptake Efficiency, Nitrogen utilize efficiency, Grain Yield
Accepted for publication: May 3, 2016