We evaluated Italian ryegrass (Lolium multiflorum Lam.) establishment in a factorial of grazing intensity (intense, moderate, moderate-light, light, and no grazing, with target average sward heights of 10, 20, 30, and 40 cm in the grazed plots) and additional seeding (self-seeding with or without additional seeding) in an integrated soybean-beef cattle system in southern Brazil. Grazing treatments were imposed in winter (June–July) and followed by a direct-seeded soybean crop (November). The establishment was quantified prior to the stocking periods in 2017 and 2018, corresponding to self-seeding from 2016 and 2017. Intense grazing impaired ryegrass re-establishment, resulting in larger individual plants (0.54 vs. 0.15 g dry matter plant⁻¹) but lower population density (57 vs. 1,355 plants m⁻²) than in the other treatments. Additional broadcast ryegrass seeding did not fully compensate for the reduced natural reseeding in this treatment. The addition of seeds under intense grazing increased plant population density to values comparable to moderate grazing intensities but reduced individual plant mass, limiting herbage mass attained by the end of the pasture establishment phase. Contrastingly, the various combinations of individual plant mass and population density were sufficient to maintain herbage masses in moderate to light grazing intensities that were comparable to that in the ungrazed treatment, regardless of seed addition (63 vs. 180 g DM m⁻² for intense grazing vs. the average of other treatments over the whole establishment phase). Moderate grazing, e.g., target sward heights of 20 cm or greater, is necessary to achieve a system that can sustain itself without seed addition.

中文翻译：

---

密集的冬季放牧损害了随后意大利黑麦草在大豆牧场轮作中的重建

我们以放牧强度（强烈，中度，中度轻度，轻度和不放牧）的因子对意大利黑麦草（黑麦草）进行了评估，放牧的目标平均草皮高度为10、20、30和40 cm地块）和额外播种（带或不带额外播种的自种）在巴西南部的综合大豆-牛肉牛系统中。在冬季（6 月至 7 月）实施放牧处理，然后是大豆直播（11 月）。在 2017 年和 2018 年的放养期之前对建立进行了量化，对应于 2016 年和 2017 年的自播。强烈放牧损害了黑麦草的重建，导致更大的单株植物（0.54 与 0.15 克干物质植物^-1) 但种群密度低于其他处理（57 对 1,355 株 m ^-2）。额外的广播黑麦草播种并没有完全弥补这种处理中自然重新播种的减少。在强烈放牧下添加种子将植物种群密度增加到与中等放牧强度相当的值，但减少了单个植物的质量，限制了牧场建立阶段结束时达到的牧草质量。相比之下，无论种子添加量如何（63 对 180 g DM m ^-2），个体植物质量和种群密度的各种组合足以将牧草质量保持在与未放牧处理相当的中等至轻度放牧强度集中放牧与整个建立阶段其他处理的平均值）。适度放牧，例如目标草坪高度为 20 厘米或更高，对于实现无需添加种子即可维持自身的系统而言是必要的。