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Background and aims <p>In highly weathered soils of central Amazonia, where nutrients such as phosphorus (P) and base cations are scarce, fertilization experiments have demonstrated above- and belowground effects on total net primary productivity (NPP). This study examined how fine root stocks and turnover responded to added nutrients over a two-year period. We predicted that adding a limiting nutrient would decrease fine root stocks and increase turnover, with the strongest effects from P, followed by base cations, and no response to N.</p> Methods <p>Fine roots (&lt; 2&#xa0;mm diameter) were sampled from the 0–30&#xa0;cm soil layer in a low-fertility primary forest in central Amazon subjected to a large-scale factorial experiment adding P, base cations, and N over two years. Fine root turnover was calculated as the ratio between fine root productivity, measured with in-growth cores, and fine root stock.</p> Results <p>Fine root stocks remained unchanged with nutrient addition. However, P increased root turnover by 23% and 48% in the first and second years, respectively, while base cations addition reduced turnover by 24% in year two. N had no significant effect, though a trend toward reduced turnover was observed in the second year.</p> Conclusion <p>The results of this study show that fine root standing stock and turnover in the central Amazon are regulated by soil nutrient availability, especially P and base cations. The contrasting responses observed suggest distinct belowground resource-use strategies for different nutrients, shaped by the nutrient specific mobility in the soil and physiological role in the plant.</p>

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Phosphorus and base cations drive contrasting root dynamics in a central Amazon forest

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年2月2日

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  • Jéssica Schmeisk-Rosa,
  • Kelly M. Andersen,
  • Amanda L. Cordeiro,
  • Anna Carolina Martins Moraes,
  • Ana Cláudia Francisco Salomão,
  • Rafael Leandro de Assis,
  • Raffaello Di Ponzio,
  • Renata Vilar de Almeida,
  • Maria Pires Martins,
  • Hellen Fernanda Viana Cunha,
  • Nathielly Pires Martins,
  • Sheila Trierveiler de Souza,
  • Gyovanni Augusto Aguiar Ribeiro,
  • José Augusto Salim,
  • Érick Oblitas,
  • Sara Deambrozi Coelho,
  • Adriana C. Conceição,
  • Bruno Takeshi Tanaka Portela,
  • Oscar J. Valverde-Barrantes,
  • José Luís C. Camargo,
  • Patrick Meir,
  • Anja Rammig,
  • Iain P. Hartley,
  • Carlos Alberto Nobre Quesada,
  • Laynara F. Lugli

摘要

Background and aims

In highly weathered soils of central Amazonia, where nutrients such as phosphorus (P) and base cations are scarce, fertilization experiments have demonstrated above- and belowground effects on total net primary productivity (NPP). This study examined how fine root stocks and turnover responded to added nutrients over a two-year period. We predicted that adding a limiting nutrient would decrease fine root stocks and increase turnover, with the strongest effects from P, followed by base cations, and no response to N.

Methods

Fine roots (< 2 mm diameter) were sampled from the 0–30 cm soil layer in a low-fertility primary forest in central Amazon subjected to a large-scale factorial experiment adding P, base cations, and N over two years. Fine root turnover was calculated as the ratio between fine root productivity, measured with in-growth cores, and fine root stock.

Results

Fine root stocks remained unchanged with nutrient addition. However, P increased root turnover by 23% and 48% in the first and second years, respectively, while base cations addition reduced turnover by 24% in year two. N had no significant effect, though a trend toward reduced turnover was observed in the second year.

Conclusion

The results of this study show that fine root standing stock and turnover in the central Amazon are regulated by soil nutrient availability, especially P and base cations. The contrasting responses observed suggest distinct belowground resource-use strategies for different nutrients, shaped by the nutrient specific mobility in the soil and physiological role in the plant.