施肥時期對香茅草產量及油分品質之影響

The Effect of Timing of Fertilizations on Yield of Fresh Grass and Oil Content and Quality in Citronella Grass

徐原田(Y. T. Shyu) ； 楊永裕(Y. Y. Yang)

《中華農業研究》 21卷4期 (1972/12) Pp. 280-289

https://doi.org/10.29951/JARC.197212.0009

摘要

爲探求香茅草生育期中適當的三要素肥料施用時期，以提高香茅草之含油率及油品質，舉行本試驗。自民國57年(1968)7月至60年(1971)6月，連續3年。供試材料爲本省一般栽培之爪哇型香茅草(Java type citronella grass)，分5個施肥期處理。全年施肥量爲N:P2O5:K2O=120:60:60kg/ha。茲將試驗結果摘述如下：
1.就香茅草生育特性言，其株高與分蘖數隨香茅草生育而顯著遞增。但在生育中受氣候、施肥期與肥料之影響爲最。在嚴冬季節香茅草倍受影響，鮮草收量銳減。
2、3年中鮮草收量以第2年爲最多，而3年總收量（表2）則以(B)處理（N, P2O5及K2O肥料分三份在7月中旬，10月中第一割及2月中第二割後分別施用）爲最高，有顯著增產之效，而以(C)處理（P2O5及K2O肥料分三份，施法同(B), N肥以1/2施於7月中旬，餘1/2分三份，於每次收割前2個月施用）爲最低，共他處理間鮮草量差異不顯著，表示鮮草量受各種不同施肥期之影響，氮肥分次在收割後立即施用較佳，而磷、鉀肥分次施用與否，對鮮草產量影響不大。
3.各處理收油量與含油率隨年度、氣候及施肥期而互異，資料顯示3年收油量及含油率（表3、4）以(E)處理（P2O5及K2O肥於7月中旬一次施用，N肥分三份，施法同(B)）爲最高，(B)處理次之，而以(D)處理（N肥施法同(B), P2O5及K2O肥分三份，於收割前2個月分別施用）最低。顯示P2O5及K2O肥於每次收割前2個月施用有降低油量及含油率之趨勢。
4.香茅油(Citronella oil)之香茅醛(Citronellal)量之多寡與施肥期不同有關（表5），以(E)處理最高，顯示P2O5及K2O肥宜早期施用，N肥宜分次施下，均可提高香茅醛含量。
5.各處理間香茅草之含油量及油品質受P2O5及K2O肥施用時期是否適當之影響較大。

並列摘要

The purpose of this study was to investigate the effects of the timing of fertilizations on the yield of fresh grass as well as oil content and quality of citronella oil. The experiments were conducted at Taipei for a period of three years, from July of 1968 to June, 1971. The variety, Java type of citronella grass was used. There were five different timing of fertilizations in this study. The total amount fertilizers of N, P2O5 K2O were 120,60 and 60 kg/ha, respectively. The results are summarized as follows:
1. The plant height and the number of tillers of citronella grass increased with the plant growth. However, the plant growth was not only influenced by timing of fertilizations, hut also by climate conditions. The yield of fresh grass was significantly decreased during the winter.
2. In the period of three years, the second year yielded the highest fresh grass. Comparing the treatments of three years average, the treatment B (split the N, P2O5 and K2O fertilizer into three parts, each part of them applicated at middle July, middle Oct. (1st harvest) and middle Feb. (2nd harvest) ) obtained the highest fresh grass, and the treatment C (applicated the P2O5 and K2O fertilizer as treatment B did, the 1/2 amount of N fertilizer applicated at middle July, split the remains into three parts, applicated each of them at two months before each harvest) harvested the lowest yield. The yields among other treatments were not significantly different. The results indicated the timing of nitrogen fertilizations affected the yield of fresh grass, the yields increased when nitrogen applied following harvesting. However, the effects of potassium and phosphorus fertilizers on fresh grass were limited.
3. The yield of oil and oil content of citronella grass varied with seasons, years and timing of fertilizations. According to the three years data, the treatment E (applicated N fertilizer as treatment B did, applicated P2O5 and K2O fertilizer at middle July once) obtained the highest yield of oil and percentage of oil content, followed by the treatment B, the treatment D (applicated N fertilizer as treatment B did, Split P2O5 and K2O fertilizer into three parts, applicated each part at two months before each harvest) yielded the lowest. The results showed fertilizers of potassium and phosphorus applied two months before harvest decreased the yield of oil and oil content.
4. The timing of fertilizations affected the content of citronellal in citronella oil. The treatment £ showed the highest in citronellal content indicating that the quality of citronella oil can be improved by applying potassium and phosphorus fertilizers at the early stage of growth and applying nitrogen fertilizers two months before harvest.
5. The oil content of citronella grass and the quality of citronella oil was mainly influenced by the timing of potassium and phosphorus fertilizations.