Research Highlights

Multiple soil nutrient competition between plants, microbes, and mineral surfaces

January 18, 2016


  • Develop, calibrate, and test a nutrient competition model that accounts for multiple soil nutrients and abiotic consumers.
  • Calibrate and test model against N and P fertilization experiments.
  • Predict dynamic competitive regimes.


  • Model includes three primary soil nutrients (NH4+, NO3-, POx) and five competitors (plant roots, decomposing microbes, nitrifiers, denitrifiers, and mineral surfaces).
  • Competition modeled with the Equilibrium Chemistry Approximation (ECA).
  • Calibrated at a tropical forest site (Tapajos) and tested at two other tropical forest sites (Hawaii and Puerto Rico).


  • Model accurately replicated the experimentally manipulated forest responses that were not used in model calibration.
  • Relative competitiveness of consumers was dynamic. For NH4, nitrifiers and decomposers were comparably competitive and out-competed roots.
  • These mechanisms are being integrated in ALM and tested against >80 field studies.

Zhu, Qing, William J. Riley, Jinyun Tang, and Charles D. Koven. January 18, 2016. “Multiple Soil Nutrient Competition Between Plants, Microbes, and Mineral Surfaces: Model Development, Parameterization, and Example Applications in Several Tropical Forests.” Biogeosci., 13(1):341–363. doi:10.5194/bg-13-341-2016.