NUTRIENT LIMITATIONS TO PLANT-GROWTH DURING PRIMARY SUCCESSION IN HAWAII-VOLCANOS-NATIONAL-PARK

We determined the effects of nutrient amendments on plant growth in three tropical montane rainforest sites representing a sequence of soil ages (<30, 200, and similar to 2000 y). Factorial fertilization with nitrogen, phosphorus, and all other essential nutrients (combined) was applied to the two younger sites; only nitrogen was applied to the oldest one. Nitrogen supply represented the most important limitation to plant growth in the two younger sites; additions of nitrogen caused significant increases in tree diameter increment, height growth, litterfall, and most other growth-related parameters. In contrast, nitrogen additions had no significant effect on plant growth in the oldest site. Phosphorus additions increased extractable soil phosphorus and plant tissue phosphorus, but did not increase plant growth at the young sites. The results are consistent with Walker and Syers' (1976) model for the control of nutrient limitation during soil development.