Morphogenesis of stockpiled Marandu, Piatã, Xaraés and Paiaguás brachiariagrass cultivars

ABSTRACT The objective this study was to identify differences in the morphogenic patterns of four Urochloa brizantha cultivars (marandu, piatã, xaraés and paiaguás grasses) during the stockpiling period. A completely randomized design was used, with three replications, in experimental plots of 9m². The evaluations took place over 2 years. The grasses were stockpiled for 92 (Year 1) and 95 (Year 2) days. The leaf appearance rate of paiaguás grass was higher, compared to other grasses. In Year 1, the stem elongation rate of xaraés grass was higher than other grasses. At the end of stockpiling period of Year 1, the tiller population density (TPD) was higher in the paiaguás grass, intermediate in the xaraés and marandu grasses and lower in the piatã grass. At the end of the stockpiling period in Year 2, TPD was higher in the paiaguás grass canopy, intermediate in the marandu and piatã grasses canopies, and lower in the xaraés grass canopy. Paiaguás grass has greater leaf growth during the stockpiling period and is therefore suitable for use under stockpiled grazing. Xaraés grass has high stem elongation during the stockpiling period, which is why its use under stockpiled grazing must be accompanied by adjustments in pasture management.

摘要 本研究旨在明确4个臂形草（Urochloa brizantha）品种（马兰杜草、皮塔草、沙拉耶斯草与帕亚瓜斯草）在牧草蓄积期的形态发生模式差异。本试验采用完全随机设计，设置3次重复，试验小区面积为9平方米，试验周期为2年。供试牧草的蓄积时长分别为第1年92天、第2年95天。相较于其余品种，帕亚瓜斯草的叶片出现速率更高。第1年，沙拉耶斯草的茎秆伸长速率高于其余品种。第1年牧草蓄积期结束时，帕亚瓜斯草的分蘖种群密度（Tiller Population Density, TPD）最高，沙拉耶斯草与马兰杜草次之，皮塔草最低。第2年牧草蓄积期结束时，帕亚瓜斯草冠层的分蘖种群密度最高，马兰杜草与皮塔草冠层次之，沙拉耶斯草冠层最低。帕亚瓜斯草在牧草蓄积期的叶片生长量更大，因此适配蓄牧放牧模式。沙拉耶斯草在蓄积期的茎秆伸长速率较高，因此在蓄牧放牧中应用时，需配套调整牧场管理措施。