Why are Nutrient Constraints Important?
Mineral nutrients, such as nitrogen and phosphorus, are essential for plant growth in tropical forests, which primarily grow on highly weathered soils. Nutrient deficiencies can constrain photosynthesis and growth, and may limit how much forests can benefit from rising CO2 or how fast they recover following anthropogenic disturbance. Nutrient uptake by plants is associated with how their roots are distributed and function, as well as interactions between roots and soil microbes. Phosphorus (P) is considered to be the limiting nutrient in many tropical lowland forests. Co-limitation by nitrogen (N) can also play a large role in regulating the tropical forest carbon cycle.
The carbon cycles in Earth system models that incorporate nutrients are highly sensitive to nutrient uptake. Yet, data and theory for how nutrient limitations play out in tropical forests is still developing. Improving understanding of how environmental conditions, plant strategies and plant-microbe-soil interactions determine N and P uptake in tropical forests is essential to better simulating the tropical forest carbon cycle and its response to global changes. NGEE-Tropics is advancing understanding and model representation of the factors that control nutrient availability, nutrient uptake, and plant nutrient controls on carbon uptake, allocation and turnover, and post-disturbance recovery rates.
NGEE-Tropics is advancing understanding and model representation of the factors that control nutrient availability, nutrient uptake, and plant nutrient controls on carbon uptake, allocation and turnover, and post-disturbance recovery rates.
In Phase 1 of NGEE-Tropics, we address NUTRIENT CONSTRAINTS by:
- Quantifying and assessing relationships between plant physiology, traits, and allocation as influenced by soil nutrient availability
- Developing pantropical soil fertility maps
- Developing a conceptual framework for dynamically linking P availability, uptake, and N-P interactions to plant carbon uptake and allocation
- Developing a version of the NGEE-Tropics ACME-FATES model that simulates vegetation N and P dynamics