水稻之穗肥效應及診斷研究

Response of Rice Yield to Nitrogen Top-Dressing during Panicle Initiation Stage and the Diagnosis

連深(S. Lian)

《中華農業研究》 21卷1期 (1972/03) Pp. 11-17

https://doi.org/10.29951/JARC.197203.0002

摘要

爲探討穗肥必需性判定之基準，乃進行穗肥效應試驗，以檢討穗肥效果和幼穗形成期水稻營養狀態之關係，結果如下：
1.穗肥之效果和幼穗形成期之植物體全氮含量具有顯著的負相關；第一期作時幼穗形成期之植物體全氮含量如低於1.8~1.9%，則穗肥之效果顯著，反之則否。惟此基準似因環境而稍異，如臺北試驗結果，似較屏東略高，爲2.0%左右。
2．穗肥之效果和葉鞘之澱粉堆積程度大致成正相關關係。即澱粉堆積愈明顯者，穗肥效果亦愈大。但其判定之基準仍因環境而稍異，如據臺北第一期作試驗結果，第四葉葉鞘之1/2部位，若有澱粉堆積則穗肥有效，若完全無碘反應則穗肥無效。但據屏東第一期作試驗結果，所觀察之判定基準則以四葉葉鞘之3/4部位（由底部量）爲適合，即第四葉葉鞘之譽部位如有澱粉堆積，則穗肥有效。
3．由以上試驗測定結果，可獲初步結論，即穗肥之效果和幼穗形成期之植物體氮素濃度或葉鞘之澱粉堆積程度有關。惟此等穗肥需要性判定之基準則因環境、品種而稍異，應就區域別環境、品種相似者，加以試驗制定。

並列摘要

To develop a simple scheme for diagnosing the demand of nitrogen topdressing during panicle initiation stage (the stage when panicle primordium of about 1-2mm long appears in the sheath), a study on relationship between the nutritional status of rice plant and its response to the fertilizer application has been conducted. The results are as follows:
1. The response of rice plant to panicle fertilizer was observed well correlated with the nitrogen content in the plant during panicle initiation stage, i.e., the lower the nitrogen content in the plant, the higher the response of the plant to the topdressing. In the first crop, the critical nitrogen content for obtaining positive yield response as observed in the Pingtung expeirment (l933) was abut 1.8-1.9%. However, as environmental condition varies, some fluctuation seems inevitable, e.g., the critical level observed in the Taipei expeirments (both 1968 and 1969 first crop) was about 2.0%.
2. The iodine reaction of sheath during panicle initiation stage was also correlated with the response of the rice plant to panicle fertilizer, although the criteria for determining the necessity of top dressing differ considerably among localities. For instance, in the Pingtung experiment (1968 first crop) the iodine reaction on the 3/4 position (as measured from the bottom of the sheath) of the fourth leaf sheath (the sheath attached to the fourth leaf as counted from the top, including the needle leaf) was observed critical for the diagnosis, i.e,, if the reactions are mostly negative (90/100), the application of panicle fertilizer is not recommended and vice versa. However, in the Taipei expeirment (1968 and 1969 first crop) the examination of the 1/2 position was observed more adequate for the diagnostic purpose.
3. Since the criteria for the diagnosis vary somewhat according to environmental conditions and to rice varieties, it is recommended that the exact figure should be determined locally where environmental conditions and varieties are similar.