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

作者：Wright S Joseph^*; Yavitt Joseph B; Wurzburger Nina; Turner Benjamin L; Tanner Edmund V J; Sayer Emma J; Santiago Louis S; Kaspari Michael; Hedin Lars O; Harms Kyle E; Garcia Milton N; Corre Marife D

来源：Ecology, 2011, 92(8): 1616-1625.

DOI：10.1890/10-1558.1

• Barro Colorado Nature Monument, Panama
• fertilization
• fine litter
• fine roots
• nitrogen
• nutrient limitation
• phosphorus
• potassium
• tree growth
• tropics

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 40x40 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.

• 出版日期2011-8