Data from: A new theory of plant-microbe nutrient competition resolves inconsistencies between observations and model predictions

Terrestrial plants assimilate anthropogenic CO2 through photosynthesis and
synthesizing new tissues. However, sustaining these processes requires
plants to compete with microbes for soil nutrients, which therefore calls
for an appropriate understanding and modeling of nutrient competition
mechanisms in Earth System Models (ESMs). Here, we survey existing
plant-microbe competition theories and their implementations in Earth
System Models (ESMs). We found no consensus regarding the representation
of nutrient competition and that observational and theoretical support for
current implementations are weak. To reconcile this situation, we applied
the Equilibrium Chemistry Approximation (ECA) theory to plant-microbe
nitrogen competition in a detailed grassland 15N tracer study and found
that competition theories in current ESMs fail to capture observed
patterns and the ECA prediction simplifies the complex nature of nutrient
competition and quantitatively matches the 15N observations. Since plant
carbon dynamics are strongly modulated by soil nutrient acquisition, we
conclude that (1) predicted nutrient limitation effects on terrestrial
carbon accumulation by existing ESMs may be biased and (2) our ECA-based
approach may improve predictions by mechanistically representing
plant-microbe nutrient competition.