Effects of Nitrogen Application Rates on Nitrogen Use Efficiency of Rice

• Main Authors: Chih-Ching Chuang, 莊志慶
• Other Authors: Ching-Ping Liu Ph.D
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/74035384035104733279

碩士 === 國立嘉義大學 === 農學研究所 === 94 === Nitrogen fertilizer functions well in raising the rice yields. The application rate of nitrogen has been increased along with the demands of the high yields from the farmers. However, high nitrogen fertilizer application is harmful to the agricultural ecology. In addition, it is also disadvantaged to maintain the balance between the cost and productivity. Accordingly, this study used different nitrogen application rates to investigate the nitrogen use efficiency and characters of rice yield and quality in every growth period. The results of this study would serve as a valuable reference for the rice breeding and culture management in the future. The results indicated total nitrogen contents of rice plants were increased along with the increase of nitrogen application rates. When the nitrogen application rate was raised, the nitrogen absorbing ability was relatively raised. The total dry weight was also raised and the grain yield was, further, increased. Under different nitrogen fertilizer treatments, the nitrogen use efficiency and absorbing 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 absorbing efficiency of the second crop was higher than that of the first crop. The nitrogen use efficiency and absorbing 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 TK 8 was decreased in the increase of nitrogen application rate in the second crop. All the relations between palatability value and nitrogen use efficiency and uptake efficiency were positive correlated in these two varieties in the first and second crops except the relation between nitrogen use efficiency and palatability value was nonsignificant in the first crop of TK 8. The ratio of the accumulated nitrogen in the stems and leaves before the heading date of the plants in the first crop and the nitrogen transferred to grain in the grain filling period was 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 critical to note in the procedure of looking for high quality rice culture.