品種、種植期與收穫期對青割玉米產量與品質的影響

為了解品種、種植月份及不同收穫期對青割玉米產量與品質的影響，本研究以台南19號、台農3號及台南21號等三個青割玉米推廣品種為材料，於91年春作2、3、4月種植並分別於吐絲後7天、14天、21天及28天收穫調查。種植月份對株高、產量有較大影響；收穫期影響穗／桿比例、產量及乾物率；品種僅在穗／稿桿比例有顯著差異。隨著收穫期延後，苞穗／槁桿之乾重比由0.49提高到1.11；乾物率每日約提高4%，鮮重產量由每公頃45公噸降至40.6公噸，乾重產量由7.8公噸上升至12.0公噸。全株之營養成分方面，中洗纖維、酸洗纖維、中洗纖維消化率（NDFd）及澱粉受收穫期的影響較大；粗蛋白質及試管真消化率（IVTD）則受種植月份的影響較大；品種僅在中洗纖維有顯著效應。種植月份與收穫期在多個營養成分有顯著交感，月份間的趨勢並不一致，以主效應的平均值而言，4月份種植者之粗蛋白質含量高，NDFd與IVTD較低；隨著收穫期粗蛋白質、酸洗纖維、水溶性碳水化合物降低，澱粉提高，IVTD48（48小時培養）在後期降低1.4%。台南21號的中洗纖維顯著較高。不同於全株之狀況，槁桿在多個成分有顯著的品種差異；槁稈之中、酸洗纖維在各收穫期間變動幅度小，IVTD48僅在後期小幅下降。苞穗的IVTD48約較槁桿高12%，隨著成熟，苞穗的WSC降低、澱粉升高，但IVTD30（30小時培養）在前期下降、IVTD48無顯著變化。全株的營養價值是槁桿與苞穗的組合，部分營養成分在種植月份間的變動趨勢不一，推論是環境效應影響植株供源與積儲比例及其成分所造成。

關鍵字

成熟度；營養成分；中洗纖維消化率；試管真消化率

並列摘要

In order to understand the effects of variety, planting date and harvesting time on yield and nutritive value of forage corn, three cultivars in Taiwan, i.e.; Tainung no. 3, Tainan no. 19 and Tainan no. 21, were planted monthly from February to April 2002 and harvested at 7, 14, 21, and 28 days after silking, respectively. The results showed that planting date had much more effective on plant height and yield, while harvest time did more on the ear/stover ratio, yield, and dry matter. The variety affected only the ear/stover ratio. The ear/stover ratio kept increasing with maturity from 0.49 to 1.11 and dry matter rose by 4% per day, with the maturity. At the same time, fresh weight dropped from 45 to 40.6 tons per hectare, but dry weight rose from 7.8 to 12.0 tons per hectare. From the aspect of nutrition of whole plant, neutral detergent fiber (NDF), acid detergent fiber(ADF), digestibility of NDF(NDFd), and starch were more affected by harvest time, while crude protein(CP)and in vitro true digestibility(IVTD)were obviously affected by planting date. Variety effect was found only on NDF content. There are significant interaction effects of planting dates and harvest time on several components. Comparing the means of main effects, plants planted on April had higher CP contents and lower in NDFd and IVTD. Crude protein, ADF, and WSC decreased and starch increased with maturity. On the other hand, IVTD48(IVTD of 48 hour's incubation)dropped by 1.4% during the later stage. Tainan no. 21 had the highest NDF content. As contrast to those in whole plant, significant effects among varieties were found in several components in stover. Changes in ADF, NDF of stover are little in range with harvest time and IVTD48 dropped slightly only at later stage. IVTD48 of the ear was higher by about 12% than that of stover. WSC decreased and starch increased apparently with harvest time in the ear. IVTD30(incubated for 30 hours)dropped in earlier stage, while IVTD48 didn't show significant change. The nutritive value of whole plant is the mean value of ear and stover, and the inconsistent changes in some components are referred to the consequences of environmental effects that altering the plant sink and source ratio and their chemical contents of forage corn.

並列關鍵字

Maturity ； Nutritional content ； Neutral detergent fiber digestibility ； In vitro true digestibility

主題瀏覽