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2025-03-22 12:17 本頁(yè)面
【正文】 important nutrient affecting tobacco yield and quality. As nitrogen rate increases, the following occur:? Yield increases to a point then decreases.? Leaf size increases, but leaf thickness decreases.? Total alkaloids, including nicotine, increase and sugars decrease in the cured leaf.? Maturity and ripening are delayed. ? Cured leaf darkens.? Sucker growth increases and sucker control decreases.? Leaf drop and leaf break increase. ? Blue mold is more severe.? Hornworm and aphid populations increase.氮肥的施用量和施用時(shí)間 氮素是影響煙草產(chǎn)量和質(zhì)量的最重要的營(yíng)養(yǎng)元素。隨著氮用量的增加，將會(huì)出現(xiàn)以下情況： ●產(chǎn)量增加到一定值，然后下降。 ●葉面積增大，但葉厚度減小?！裨谡{(diào)制后葉片中，總生物堿、煙堿增加，糖減少。 ●成熟延遲。 ●調(diào)制后葉片變黑。 ●腋芽數(shù)增加，腋芽控制效果降低。 ●殘傷增加。 ●霜霉病更加嚴(yán)重。 ●天蛾幼蟲(chóng)和蚜蟲(chóng)的蟲(chóng)口增加。Many growers spend considerable time choosing among sidedressers such as calcium nitrate, sodium nitrate, 30 percent UAN liquid, and 24S UAN liquid. However, the data indicate that in the southeastern United States the rate and time of application are more important than the sidedresser. Unless leaching occurs, nitrogen should not be applied after layby. Late season application delays ripening and results in variegatedunripe grades. 許多種植者花費(fèi)了相當(dāng)多的時(shí)間選擇側(cè)施肥料，比如硝酸鈣、硝酸鈉、30％的UAN(尿素硝銨)液體肥料和24S的UAN液體肥料。然而，數(shù)據(jù)表明：在美國(guó)東南部，氮肥的施用量和施用時(shí)間比側(cè)施肥料更重要。除非發(fā)生淋洗，氮肥不應(yīng)在煙草側(cè)施肥后施用。后期施用延遲煙葉成熟，導(dǎo)致雜色未熟等級(jí)的產(chǎn)生。9 / 9Topping and Sucker ControlTopping tobacco in the button stage (soon after the flower begins to appear) rather than later increases yield and body if suckers are controlled. When tobacco plants are not topped for three weeks after reaching the button stage, yields are reduced by 20 to 25 pounds per acre per day, or about 1 percent per acre per day when normal yields are in the 2,000 to 2,500poundsperacre range. 打頂和腋芽控制如果控制腋芽，煙草在現(xiàn)蕾期打頂比現(xiàn)蕾期之后打頂能夠提高產(chǎn)量、增加身份。如果煙株在現(xiàn)蕾期后三周不打頂，則每天每英畝減少產(chǎn)量20～25磅，或者在正常產(chǎn)量在每英畝2000～2500磅的范圍內(nèi)時(shí)每天減少l％的產(chǎn)量。Higher yields reduce perpound production costs for acreagerelated inputs such as chemicals, fertilizers, and some labor expenses. Topping early also improves chemical and physical qualities of the leaf by stimulating root development and alkaloid production and by reducing buildup of insects.高產(chǎn)減少了與面積相關(guān)的生產(chǎn)成本，如農(nóng)藥、肥料和一些勞動(dòng)力支出。早打頂還通過(guò)刺激根系的發(fā)育、生物堿的生成以及減少害蟲(chóng)的危害而提高煙葉的化學(xué)和物理品質(zhì)。Control of sucker growth is critical to maximizing yield because it allows the plant to concentrate resources on the production of leaves instead of suckers. Suckers can also interfere with mechanical harvesting and bee a significant source of foreign matter in cured leaves. The key to successful sucker control is proper timing of suckercide application and u
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