黃麻收穫期對於纖維產量與品質影響之研究

Abstract

(一)本省黃麻適當收穫期，過去認為乃在結有小蒴果時，?蒴果乳熟期。如收穫期提早，必使產量減低。延遲收穫，產量增加，但品質不佳。近年推廣之品種多遲熟，為配合輪作，常有不待結實而急收之趨勢，是否影響產量及品質，實有作比較研究之必要。 (二)黃麻收穫期對於纖維產量與品質影響之研究，自56年起至57年止連續舉辦2年，所用品種為臺農1號，試驗計分"播種及生長日數為準"及"花期為準"收獲者兩部份。一則探知黃麻播種後生長日數以何時為提高纖維產量與品質之最適當時期，再則探求以花期後收獲是否對纖維產量與品質有提高之效。比較二者之優劣，以確定黃麻之最適當收穫期以供實用推廣，生產價廉物美產品，充裕本省製麻原料，剩餘產品進而拓展外銷。 (三)就黃麻增產之適當收穫期而言，收穫期處理間差異極顯著，顯示黃麻最適當收穫期應為播種後生長120天至140天或始花期至始花後10天，?生育期128天至138天而其每公頃產量順序為始花後10天>始花期>播種後生長130天>播種後生長140天>播種後120天>始花後30天>始蕾期>始花後20天>播種後生長110天>播種後生長100天收穫。 (四)黃麻過遲收獲，纖維產量未必增加，黃麻生長後期，?始花後30天收獲者，因氣候及環境影響，枯死株高達20.2%影響纖維產量甚大，疏不正常。 (五)黃麻纖維品質以播種後生長120天至130天或始花後20天至30天收獲者，拉力負荷較高，結節力、耐磨力、耐屈力亦佳，惟黃麻纖維品質優劣，對於浸練時間之長短有顯著影響，?浸練愈久，拉力、結節力、耐摩力、耐屈力則愈低下。故欲提高黃麻纖維品質對縮短浸練日數(5~6日在濕熱天氣下)，為提高精洗麻品質之最有效方法。 (六)年度與處理間交感效應，差異剛顯著，顯示黃麻播種後，生長100天及110天收獲者或始花後30天收獲者，56年較57年產量高，係56年生長前期雨量較少未遇雨害，57年生長後期雨量豐沛黃麻生長旺盛影響不大所致，但其他延長收獲日數處理蓋因57年8、9兩月雨量過多，而罹病株達20.2%故產量減低。 由此獲知黃麻播種後120天及130天或始花期、始花後10天及20天收獲者，收獲株數整齊，產量穩定，無論年別皆具效果。 1. During the past, it was generally agreed that the good yield of high quality jute fiber were usually obtained if plants were harvested by the milky stage. It was found that jute harvested before this stage gave lower yield, and the higher yield but tow quality retted fiber was expected if plants were harvested after this stage. Due to the highly intensive cropping system in Taiwan, jute plants are often harvested far before this right stage. Therefore, information is needed as to the point in maturation at which retted fiber of high quality can be obtained by the suitable harvesting periods. 2. This study was conducted at Tainan, Taiwan in 1967 and 1968 to evaluate the effects of harvesting periods on fiber yield and quality of jute. Highly significant (% level) differences among harvesting periods for fiber yield were found in both years. The order of fiber yield per hectare by jute plants harvested at the different growing periods or flowering stage was 10 days after the initial flowering >the initial flowering > 130 days after sowing >140 days after sowing > 120 days after sowing >30 days after the initial flowering >20 days after the initial flowering >110 days after sowing >100 days after sowing. 3. High percentage of dead plants caused by the weather conditions appeared to be greatly associated with lower yield in late harvesting periods when results from 1967 and 1968 were compared. 4. Jute fiber of high physical properties was obtained by harvesting plants in 120 to 130 days after sowing, or 20 to 30 days after the initial flowering. Data showed that the long period of retting of fresh fiber had a detrimental effect on the fiber quality. If the fresh fiber was left in retting for longer than 6 days under the warm humid conditions, low quality of jute retted fiber was expected. 5. The field experimental data suggested that year to year variation in yield increase was small. The difference in fiber yield increase on jute between the 1967 and the 1968 season was the result of differences in harvesting periods. The increase in retted fiber yield, as the quality of jute fiber was improved, was greater when jute platns were harvested in 120 to 130 days after sowing or 20 to 30 days after the initial flowering, as compared with other harvesting.