種植期、收穫期及品種對青貯玉米發酵品質的影響

The effect of planting date, harvest date and variety on fermentation characters of corn silage

王紓愍(Shu-Min Wang) ； 陳嘉昇(Chia-Sheng Chen) ； 游翠凰(Tsui-Huang Yu) ； 劉信宏(Hsin-Hung Liu)

《畜產研究》 40卷1期 (2007/03) Pp. 37-47

摘要

為了解不同種植期及收穫時期對青貯玉米發酵品質的影響，本研究以推廣品種台農3號、台南19號及台南21號為材料，分別於2月、3月及4月種植，再於吐絲後7天、14天、21天及28天收穫，進行實驗規模青貯，青貯40天後開封測定青貯品質。試驗結果顯示，種植月份與收穫時間明顯影響青割玉米青貯前組成、青貯發酵與青貯品質的表現。三個品種的表現相當一致，青貯前材料以台南21號之水溶性碳水化合物含量略低，台南19號的乾物含量略低，而青貯結果，除台南21號之乳酸含量略低外，其餘性狀均無顯著品種差異。青貯前乾物率均隨成熟度增加而增高，而水溶性碳水化合物含量則隨之下降，但不同種植月份之變動幅度與速率不一。2月種植之水溶性碳水化合物含量較高，4月份種植者收穫時已進入雨季，初期乾物率較低。青貯發酵後，乙酸含量明顯隨收穫成熟度之增加而降低；乳酸含量則相反，以較晚收穫者較高，但無遞增現象；丁酸含量均極低，各處理無顯著差異；丙酸含量亦低，但有隨收穫成熟度增加而降低之趨勢。2月種植者各收穫期之青貯料pH值均低於4、青貯品質評分均高於90；3月種植與4月種植，吐絲後14天前收穫之青貯品質評分較差。本試驗結果說明青割玉米可調製為優良青貯料的割期範圍廣，但由於不同環境條件導致之植體成分差異，提前收穫有不利青貯發酵之風險。此外，植體成分與各項青貯指標的關係亦在本文中討論。

關鍵字

青割玉米 ； 水溶性碳水化合物 ； 乾物率 ； 青貯料

並列摘要

The purpose of this study was to investigate the effect of variety, planting date and maturity stages on fermentation characters of corn silage. Three extension varieties of forage corn, Tainung no. 3, Tainan no.19, and Tainan no.21 were used in this study. Forage corns were planted in February, May and April, and were harvested at 7, 14, 21, and 28 days after silking, and then ensiled in laboratory scale for 40 days. Comparing the ensiling characters, except that water-soluble carbohydrates content of Tainan no.21 and dry matter content of Tainan no.19 were lower, the other performances of these three varieties were similar. With regard to silage quality, there was no difference among varieties, except the lower lactic acid content in Tainan no.21. Chemical components of pre-ensiling plants, fermentation situations and silage quality were affected by planting month and maturity. Contents of moisture and water-soluble carbohydrates of ensiling materials decreased with maturity by different ranges and rates. Forage corn planted in February had higher watersoluble carbohydrates, while those planted in April, harvested early had lower dry matter content due to the rainfall. Acetic acid contents decreased and lactic acid contents increased as maturity increased. Butyric acid contents of all treatments were very low and there were no difference among them. Propionic acid contents were low and decreased as maturity increased. The pH value of all treatments planted in February were below 4 and their Fleig's score were above 90. The silage quality of which planted in May and April and harvested younger were worse than those harvested later. Our results showed that the maturity for good quality ensiling ranged widely. However, advancing harvest might be detrimental for ensiling owing to the difference of plant composition under different environment. Correlations among plant component and each ensiling character were also discussed in this study.

並列關鍵字

Water-soluble carbohydrates ； Dry matter ； Silage quality