Integrated farming systems are promising strategies towards land-use efficiency and sustainable agriculture. The integrated crop-livestock-forestry (ICLF) system stablish complex interactions were synergies or competition depend on the arrangements throughout time and space. Fine root (≤2 mm) growth dynamics of crops, pasture and trees remains unclear when these species are integrated. We aimed to assess root growth dynamics after Eucalyptus urograndis introduction into an integrated crop-livestock (ICL) system. Previous ICL area was used as a reference. We assessed ICLF 1.9, 4.3 and 7.5 m distances from tree rows, starting the study when trees had three years of age. Eucalyptus rows were spaced 15 m apart and integrated to annual crops and pasture. We evaluated the root growth under two different successional periods: (i) corn cultivation interspaced with palisade grass (Urochloa brizantha); and (ii) a pasture, when palisade grass was grazed. We tracked fine root length using the minirhizotron technique, capturing 3200 images scanning up to 70 cm soil depth. Data of photosynthetically active radiation (PAR) transmission, soil bulk density, rainfall and air temperature were used as complementary information to support the discussion. Our results showed that Eucalyptus trees impaired root growth of annual crops cultivated in the interrow position, regardless of distance from the row. From 31 to 80 days after corn germination, root length production in ICLF was reduced by 120–179 cm m⁻².d⁻¹ along the tree interrow space. For the pasture period, total produced root length density reduced 6% at 1.9 m but increased 25% at 4.3 and 7.5 m, when compared to ICL. Shade of Eucalyptus trees at ICLF 1.9 m position, with PAR transmission mainly below 60%, sharply impaired root growth. Eucalyptus roots represented 12% from total root length produced in ICLF system, and 38% of these roots had positive ectomycorrhizal status. In conclusion, under Eucalyptus trees higher than 20 m, pasture of palisade grass is more adaptable than corn when considering the root growth dynamics of our studied ICLF arrangement. Based on our findings, corn intercropped with palisade grass should not be introduced in future management of the ICLF system, unless part of the trees is chopped to reduce light competition. However, implemented pasture of palisade grass showed belowground synergies with Eucalyptus, increasing root growth in intermediary interrow positions and emerging new fungal symbiosis, which could be playing important functions in soil, as soil carbon storage and nutrient cycling.

综合农业系统是实现土地利用效率和可持续农业的有前途的战略。综合作物-畜牧-林业（ICLF）系统建立复杂的相互作用是协同或竞争取决于整个时间和空间的安排。当这些物种被整合时，作物、牧场和树木的细根 (≤2 毫米) 生长动态仍不清楚。我们的目的是评估将Eucalyptus urograndis引入综合作物 - 牲畜 (ICL) 系统后的根生长动态。以前的 ICL 区域被用作参考。我们评估了 ICLF 距树行 1.9、4.3 和 7.5 m 的距离，并在树木年满三年时开始研究。桉树行间距为 15 m，并与一年生作物和牧场融为一体。我们评估了两个不同演替时期的根系生长：（i）玉米种植与栅栏草（Urochloa brizantha）；(ii) 牧场，当栅栏草被放牧时。我们使用 minirhizotron 技术跟踪细根长度，捕获 3200 幅图像，扫描深度达 70 厘米。光合有效辐射 (PAR) 传输、土壤容重、降雨量和气温的数据被用作支持讨论的补充信息。我们的结果表明，桉树无论距行的距离如何，树木都会损害在行间位置种植的一年生作物的根系生长。从玉米发芽后 31 天到 80 天，ICLF 中的根长产量沿着树的行间空间减少了 120-179 cm m ^-2 .d ^-1。在牧场期间，与 ICL 相比，总生产根长密度在 1.9 m 处减少了 6%，但在 4.3 和 7.5 m 处增加了 25%。ICLF 1.9 m 位置的桉树树荫，PAR 传输主要低于 60%，严重影响根系生长。桉树根占 ICLF 系统产生的总根长的 12%，其中 38% 的根具有阳性外生菌根状态。总之，在桉树下考虑到我们研究的 ICLF 布置的根系生长动态，对于高于 20 m 的树木，栅栏草的牧场比玉米更具适应性。根据我们的研究结果，在 ICLF 系统的未来管理中不应引入与栅栏草间作的玉米，除非部分树木被砍伐以减少光竞争。然而，栅栏草的实施牧场显示出与桉树的地下协同作用，增加了中间隔行位置的根系生长和新的真菌共生，这可能在土壤中发挥重要作用，如土壤碳储存和养分循环。