氮型態對木荷苗木生長及形質之影響

Effects of Nitrogen Sources on Seedling Growth and Quality of the Chinese Guger Tree (Schima superba Gard. et Champ.)

許原瑞(Yen-Ray Hsui) ； 郭幸榮(Shing-Rong Kuo) ； 洪富文(Fu-Wen Horng)

《林業試驗所研究報告季刊》 10卷3期 (1995/09) Pp. 353-367

https://doi.org/10.7075/BTFRI.199509.0353

摘要

本試驗係以木荷單株母樹苗木，經由穴植管育苗作業體系，進行不同比例氨態氮與硝酸態氨營養液之施肥灌注，分析經五個月施肥及三個月短期健化後之苗高生長、根頸直徑生長、光合色素含量、菌木形質及培育介質之變化，以瞭解穴植管育苗作業下氮型態對苗木生長及形質之影響。試驗結果顯示混合氮源可獲得較佳之高生長、根頸直徑生長及苗木形質。以氨態氮/硝酸態氮之比為4/2者最佳。就單一型態氮肥之效應而言，則氨態氮優於硝酸態氮。僅施用硝酸態氮將使木荷苗木體內離子不平衡，影響苗木生長並產生葉脈間黃化及苗木弱小等病徵。適當之氮源供應，苗木健化期間生物量增加達2.5倍，並以根部為主，改變苗木形質，有助於苗木品質之提昇。人工介質養分含量低，無法供木荷苗木生長之需，必須添加肥料以促進苗木生長。氮肥型態影響育苗介質pH值，氨態氮引起介質酸化，硝酸態氮則具鹼化效應。混合氮源有平衡離子之功能。且可避免不適當pH值所引起之生理問題。人工介質與穴植管之應用，宜注意介質性質變化，以免影響木荷苗木生長。

關鍵字

氨態氮 ； 硝酸態氮 ； 木荷 ； 苗木生長 ； pH值

並列摘要

Seedlings of Schima superba Gard. Et Champ. were
raised in dibbling tubes containing a mixed medium of vermiculite, peat, pearlite and forest soil (V/V, 1:1:1). Liquid fertilizers composed of different ratios of ammonium and nitrate were applied to the dibbling tubes twice a week for five months and then the tubes were hardened by reducing water supply for three months. Seedling quality was determined according to its morphological attributes (seedling height and root collar diameter) measured periodically, and physiological attributes (chlorophyll and nutrient content) measured in October 1993 (at five months) and January 1994 (at eight months). Changes in the chemical properties of the medium (pH and concentration of N. P. K. Ca, and Mg) were examined at the end of the fertilization (at five months) and hardening (at eight months) periods.
The early growth in height and root collar diameter, and physiological attributes of seedlings fertilized with a combines nitrate and ammonium mixture appeared better than those with only a single nitrogen form alone. Of the single nitrogen forms, ammonium had a better effect on growth than nitrate. When nitrate us was as the sole nitrogen source, seedlings grew slowly and showed interveinal chlorosis, which may have been induced by a nutrient imbalance. In late autumn, hardening induced increased accumulation of nutricnts which sould benefit and improve seedling quality.
Since the nutrient content of the medium was too low to support seedling growth, fertilization was required for the dibbling tube system. As to nitrogen sources, ammonium acidified the medium, while nitrate alkalized the medium. For raising healthy seedlings, the medium in dibbling tubes should be monttored for changes in pH and nutrient status.

並列關鍵字

ammonium ； nitrate ； Schima superba ； seedling growth ； medium pH