【摘要】 土壤养分供给能力显著影响甘蔗产量及品质。中国蔗区普遍存在土壤酸化、养分失衡等问题，严重制约甘蔗产业可持续发展，揭示土壤–植物系统养分互作机制对优化田间管理策略具有重要科学价值。本研究旨在解析区域土壤化学计量特征对甘蔗叶片养分吸收的驱动机制，明确土壤酸化与养分限制的关键阈值，为精准施肥与土壤改良提供理论依据和技术支撑。采用网格布点法系统采集121个典型蔗田的土壤（0～30 cm）及对应甘蔗叶片样品，测定土壤pH及养分，包括有机质、全氮、全磷、全钾、碱解氮、有效磷、速效钾、有效态微量元素含量。叶片样品经H₂SO₄-H₂O₂消解后，测定全氮、全磷及全钾含量。基于结构方程模型（SEM）构建土壤肥力（有机质、全氮、全磷、速效钾等）、微量元素（有效铁、锰、铜、锌）及环境因子（pH）对叶片养分的多路径驱动网络，采用最大似然估计法优化模型参数，并通过标准化路径系数（β）和决定系数（R2）量化各因子贡献度。结果表明：（1）土壤呈显著酸化特征（pH均值5.07）,78.23%样点pH≤5.5;84.75%样点有效锌匮乏（<1.5 mg/kg），而全钾（2.27%）、有效铁（59.90 mg/kg）及有效铜（1.04 mg/kg）含量较高。（2）有机质与全氮(r=0.929^**)、全磷(r=0.614^**)、碱解氮(r=0.847^**)、速效磷(r=0.642^**)、速效钾(r=0.399^**)等呈极显著正相关。（3）土壤酸化（pH<5.5）导致阳离子交换量降低26.7%，并与碱解氮(r=–0.290^**)呈显著负相关；中性微酸条件（pH 6.0～6.5）可提升磷、钾有效性。（4）土壤有效养分是驱动叶片养分的关键。本研究系统阐明滇西南甘蔗区土壤化学计量特征对甘蔗叶片养分的多路径驱动机制，量化酸化与养分失衡的定量关系。建议该蔗区施肥采用“改酸–补锌–控氮–增碳”作为甘蔗高产优质栽培与土壤可持续管理的综合方案。更多还原

【Abstract】 Sugarcane（Saccharum officinarum L.）, a crucial sugar crop in China, faces yield and quality constraints due to soil nutrient limitations. Severe soil acidification and nutrient imbalances in the southwestern Yunnan sugarcane-growing areas hinder the sustainable development of the industry. This study aimed to clarify the driving effects of soil stoichiometric characteristics on sugarcane leaf nutrient uptake, identify critical thresholds for soil acidification and nutrient limitations, and provide theoretical and technical foundations for precision fertilization and soil improvement. Soil（0-30 cm depth） and leaf samples were systematically collected from 121 sugarcane fields across nine townships in Lianghe County, Yunnan Province using a grid-based sampling strategy. Soil parameters analyzed included pH, organic matter, total nitrogen, total phosphorus, total potassium, alkaline nitrogen, available phosphorus, available potassium, and DTPA-extractable micronutrients. Leaf nutrients（total nitrogen, total phosphorus, total potassium） were analyzed after H₂ SO₄-H₂O₂ digestion. Structural equation modeling（SEM） was employed to construct multi-path networks linking soil fertility（organic matter, total N/P/K, available nutrients）, micronutrients（Fe, Mn, Cu, Zn）, and environmental factors（pH） to leaf nutrient dynamics. Model parameters were optimized via maximum likelihood estimation, with standardized path coefficients（β） and determination coefficients（R2） quantifying factor contributions. Soils exhibited pronounced acidification（mean pH=5.07）, with 78.23% of samples ≤pH 5.5. Zinc deficiency（<1.5 mg/kg） occurred at 84.75% of sites, while TK（2.27%）, available Fe（59.90 mg/kg）, and available Cu（1.04 mg/kg） remained relatively high; Organic matter correlated strongly with TN(r=0.929^**), TP(r=0.614^**), AN(r=0.847^**), AP(r=0.642^**), and AK(r=0.399^**), indicating its central role in nutrient retention. Soil acidification（pH<5.5） reduced cation exchange capacity by 26.7% and negatively correlated with AN(r=–0.290^**). Neutral to slightly acidic conditions（pH 6.0–6.5） enhanced phosphorus and potassium availability. Soil available nutrients emerged as pivotal drivers of leaf nutrient assimilation. This study systematically illustrated the multi-path regulatory mechanisms of soil stoichiometric traits driving sugarcane leaf nutrient uptake in southwestern Yunnan’s sugarcane belt, quantitatively linking acidification with nutrient dysregulation. It is proposed that an integrated fertilization strategy—“ameliorate acidity-supplement zinc-regulate nitrogen-enhance carbon” should serve as the technical paradigm for high-yield sugarcane cultivation and sustainable soil management, which also could be universally referred by the agricultural ecosystems in tropical and subtropical acidic soils.更多还原