In order to utilize alfalfa (Medicago sativa L.), alone or in mixtures with grasses, defoliation management practices must be evaluated to assess their performance. The objective was to determine the forage accumulation (FA) and nutritive value of alfalfa grown as a monoculture (ALF) and in mixtures with tall fescue [Lolium arundinaceum (Schreb.) Darbyish] (ATF) or bermudagrass [Cynodon dactylon (L.) Pers] (ABG) subjected to four harvest intervals (clipped every 21, 28, 35, and 42 d). The study was conducted in Crossville, TN, and Charleston, OH, during the 2016 and 2017 growing seasons, and in Salisbury, NC, during the 2017 and 2018 growing seasons. Harvest intervals of 35 d or greater showed optimal FA, with greatest productivity in spring. In summer, the plot productivity of ATF was not different from ABG. The ATF mixture was superior to ABG in FA for the entire season. Although tall fescue can be very competitive with alfalfa in mixtures, it results in greater FA while reducing weed competition. Botanical composition indicated greater weed infestation in ALF than in mixtures. Growing alfalfa–grass mixtures can increase sward crude protein compared with grass monocultures (average of 128 g kg^–1 for ATF and 161 g kg^–1 for ABG). We conclude that harvest intervals of 35 d or longer should be adopted to provide greater FA, and the ALF and ATF treatments resulted in superior FA compared with ABG in the southern United States.

中文翻译：

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苜蓿与高羊茅和狗牙根混合对牧草积累、植物成分和营养价值的比较

为了单独或与草混合使用苜蓿 ( Medicago sativa L.)，必须评估落叶管理实践以评估其性能。目的是确定作为单一栽培 (ALF) 和与高羊茅 [ Lolium arundinaceum (Schreb.) Darbyish] (ATF) 或狗牙根 [ Cynodon dactylon(L.) Pers] (ABG) 经历四个收获间隔（每 21、28、35 和 42 天修剪一次）。该研究在 2016 年和 2017 年生长季节期间在田纳西州克罗斯维尔和俄亥俄州查尔斯顿进行，在 2017 年和 2018 年生长季节期间在北卡罗来纳州索尔兹伯里进行。35 天或更长的收获间隔显示最佳 FA，春季生产力最高。在夏季，ATF 的小区生产力与ABG 没有区别。在整个赛季中，ATF 混合物在 FA 中都优于 ABG。尽管高羊茅在混合物中与苜蓿具有很强的竞争力，但它会在减少杂草竞争的同时产生更大的 FA。植物成分表明 ALF 中的杂草侵染程度高于混合物中的杂草。与单一栽培草相比（平均 128 g kg ^–1ATF 和 161 g kg ^–1 ABG）。我们得出结论，应该采用 35 天或更长的收获间隔来提供更大的 FA，并且与美国南部的 ABG 相比，ALF 和 ATF 处理导致更好的 FA。