農民對於水稻之生產，常依賴增加施用氮素肥來增加產量，而過量使用氮素肥往往加重病害發生，在施用不同氮素肥料量的研究中，紋枯病、白葉枯病、稻熱病、葉鞘腐敗病均隨著氮素肥施用量增加而罹病度上升。而施用控釋型肥料（N：150 公斤/ 公頃）與150 斤/公頃化學氮素肥料比較，紋枯病、白葉枯病、葉稻熱病罹病較為嚴重，而穗稻熱病與葉鞘腐敗病，罹病情形有較為輕微。使用控釋型肥料，除可減少施用肥料之次數與氮素肥量，亦可減輕生育後期病害，如穗稻熱病與葉鞘腐敗之危害程度。
The Effectiveness of Controlled Release Fertilizers for Rice Disease Control
Lin, G. C., W. J. Jiang, Y. F. Wu and A. H. Cheng
Farmers often rely on increased application of nitrogen fertilizer to increase production of rice. Apply high nitrogen fertilizer for rice could often lead to the occurrence of diseases and the lose of yield. In this experiment, after we apply different amounts nitrogen fertilizer and controlled release fertilizers, we investigate the diseased degree of rice sheath blight, bacterial leaf blight, rice blast, sheath rot. Results showed that the application of high amount of the nitrogen fertilizer also increased the severity of diseases. Application of controlled release fertilizers (N=150 kg/ha) increased the disease degree of sheath blight, bacterial leaf blight and rice leaf blast, but the disease degree of rice spike blast and sheath rot were lower than that in the chemical nitrogen fertilizer (N=150 kg/ha). Applying the controlled release fertilizers could decrease the number and amount of applications, and could decrease the disease degree of the rice spike blast and sheath rot in the late growth stage.
What is already known on this subject?
Farmers traditionally use chemical fertilizers for rice growth. And they applied many times to ensure yield and quality. In adversity, cold damage farmers often apply more nitrogen fertilizer to ensure yield. This practice will the degree of rice disease. And the accurate time of panicle fertilizer application is difficult to the precisely controlled.
What are the new findings?
In this experiment, the controlled-release fertilizer was applied only once in the use time of basal fertilizer, and no fertilizer was applied in the later growth stage. therefore, number of fertilization and the occurrence of disease were all reduced.
What is the expected impact on this field?
Fertilization frequency decreased. In the early growth stage, it is necessary to increase disease prevention and control. In the later growth stage, the less occurrence of mild disease can ensure the yield, and reduce the application of pesticide and into residue problems.
Key words: Rice, Controlled release fertilizers,
Sheath blight, Bacterial leaf blight, Rice blast, Sheath rot
Accepted for publication: October 25, 2016