Roots of 'BRS Princesa' banana fertigated with humic substances and saponin-based plant extracts

ABSTRACT. This study aimed to evaluate the effects of fertigation with humic substances, with and without the addition of plant extracts, on the root system of the 'BRS Princesa' banana cultivar. The banana crop was cultivated at a spacing of 2.0 x 2.5 m and fertigated using a drip system in a dystrocohesive Yellow Latosol. The experimental design was randomized blocks, in a split-split-plot scheme with five replicates, for the following factors: humic substance doses and presence of a plant extract formulation. The treatments consisted of five doses of humic substances, based on a reference dose of 14.14 L ha-1 cycle-1, in the presence and absence of plant extract. The variable root length (cm) was subjected to variance analyses to evaluate the effect of the humic substances, either isolated or in interaction with plant extract and soil depth. The use of the plant extract increased the effect of the humic substance on root length but overshadowed its effect for the different doses of humic substance. Root length was not sensitive to increasing humic substance dose with plant extract for doses of up to 42.42 L ha-1at 0 - 0.40 m depth.

摘要。本研究旨在评估施加腐殖物质（humic substances）并添加或不添加植物提取物时，对'BRS Princesa'香蕉品种根系的影响。试验以2.0×2.5 m的株行距种植香蕉，采用滴灌系统在黏结性贫养黄色砖红壤（dystrocohesive Yellow Latosol）中实施水肥一体化管理。试验采用裂裂区布置的随机区组设计，设置5次重复，试验因素包含腐殖物质施用量与植物提取物制剂的添加与否。处理组设置为：以14.14 L·ha⁻¹·周期⁻¹为基准剂量，设置5个腐殖物质施用量梯度，分别搭配添加与不添加植物提取物两种组合。以根长（cm）为观测指标，通过方差分析评估腐殖物质单独施用，或其与植物提取物、土壤深度的交互作用效应。结果表明，添加植物提取物可增强腐殖物质对根长的促进效应，但掩盖了不同腐殖物质施用量间的作用差异。在0~0.40 m土层深度范围内，当腐殖物质施用量不超过42.42 L·ha⁻¹且添加植物提取物时，根长对腐殖物质施用量的提升无显著响应。