Seasonal and annual changes in stubble characteristics can affect the regrowth of warm-season perennial grasses. Understanding these changes and their effects on forage accumulation rate (FAR) can improve defoliation management. Our objective was to describe and relate variations in stubble characteristics with FAR during regrowth of four palisadegrasses [Brachiaria brizantha (Hochst. Ex A. Rich.) Stapf. syn. Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster], genotypes Marandu, Xaraés, Arapoty, and Capiporã, and one signalgrass [Brachiaria decumbens (Stapf.) syn. Urochloa decumbens (Stapf.) R.D. Webster] cultivar Basilisk, in southeastern Brazil. Plots were harvested at 15-cm stubble height every 28 d during the warm season and 42 d during the cool season of years 2005–2006 and 2007–2008. Stubble mass was ∼1,070 kg DM ha⁻¹ greater in the cool than warm season, whereas FAR was less in the cool season. Arapoty and Basilisk showed generally less FAR (∼45 kg d⁻¹) and stubble leaf, stem, dead material, and total mass during the warm season than more productive grasses Capiporã and Xaraés (∼63 kg d⁻¹). Leaf and canopy photosynthesis varied over seasons and years, but they were similar among grasses despite differences in stubble characteristics and FAR. Marandu accumulated more leaf in the stubble than other grasses, resulting in greater residual leaf area index, but it did not increase FAR. Under less favorable growth conditions, grasses increased stubble herbage mass (SHM). More productive grasses generally present greater SHM and leaf mass, indicating that stubble characteristics play an important role in the regrowth of brachiariagrasses.

中文翻译：

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施氮灌溉条件下与留茬特性相关的臂草再生长

留茬特征的季节性和年度变化会影响暖季型多年生草的再生。了解这些变化及其对草料积累率 (FAR) 的影响可以改善落叶管理。我们的目标是描述和关联四种栅栏草再生过程中残茬特征与 FAR 的变化 [ Brachiaria brizantha (Hochst. Ex A. Rich.) Stapf。同义词 Urochloa brizantha (Hochst. ex A. Rich.) RD Webster]，基因型 Marandu、Xaraés、Arapoty 和 Capiporã，以及一种信号草 [ Brachiaria decumbens (Stapf.) syn。尾草(Stapf.) RD Webster] 品种 Basilisk，在巴西东南部。在 2005-2006 年和 2007-2008 年的暖季每 28 天和冷季每 42 天收割 15 厘米留茬高度的地块。冷季的留茬质量比暖季高约 1,070 kg DM ha ^-1，而冷季的 FAR 较少。Arapoty 和 Basilisk 在温暖季节通常表现出较少的 FAR (~45 kg d ^-1 ) 和留茬叶、茎、死物质和总质量，而不是更高产的草 Capiporã 和 Xaraés (~63 kg d ^-1). 叶片和冠层的光合作用随季节和年份而变化，但它们在草类之间是相似的，尽管留茬特征和 FAR 存在差异。Marandu 比其他草在茬中积累了更多的叶子，导致剩余叶面积指数更大，但它没有增加 FAR。在不太有利的生长条件下，草类增加了留茬牧草量 (SHM)。更高产的草通常具有更大的 SHM 和叶质量，表明茬特征在臂形草的再生中起着重要作用。