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Potassium, phosphorus, or nitrogen limit root allocation, tree growth, or litter production in a lowland tropical forest

Research output: Contribution to Journal/MagazineJournal articlepeer-review

  • S. Joseph Wright
  • Joseph B. Yavitt
  • Nina Wurzburger
  • Benjamin L. Turner
  • Edmund V. J. Tanner
  • Emma J. Sayer
  • Louis S. Santiago
  • Michael Kaspari
  • Lars O. Hedin
  • Kyle E. Harms
  • Milton N. Garcia
  • Marife D. Corre
<mark>Journal publication date</mark>1/08/2011
Issue number8
Number of pages10
Pages (from-to)1616-1625
Publication StatusPublished
<mark>Original language</mark>English


We maintained a factorial nitrogen (N), phosphorus (P), and potassium (K) addition experiment for 11 years in a humid lowland forest growing on a relatively fertile soil in Panama to evaluate potential nutrient limitation of tree growth rates, fine-litter production, and fine-root biomass. We replicated the eight factorial treatments four times using 32 plots of 40 × 40 m each. The addition of K was associated with significant decreases in stand-level fine-root biomass and, in a companion study of seedlings, decreases in allocation to roots and increases in height growth rates. The addition of K and N together was associated with significant increases in growth rates of saplings and poles (1–10 cm in diameter at breast height) and a further marginally significant decrease in stand-level fine-root biomass. The addition of P was associated with a marginally significant (P = 0.058) increase in fine-litter production that was consistent across all litter fractions. Our experiment provides evidence that N, P, and K all limit forest plants growing on a relatively fertile soil in the lowland tropics, with the strongest evidence for limitation by K among seedlings, saplings, and poles.