Croplands cover 12% of the ice‐free land surface and play an important role in the global
carbon cycle. Light use efficiency (LUE) models have often been employed to estimate the
exchange of CO2 between croplands and the atmosphere. A key parameter in these models
is the maximum light use efficiency (ɛ*), but estimates of ɛ* vary by at least a factor 2. Here
we used 12 agricultural eddy‐flux measurement sites in North America and Europe to
constrain LUE models in general and ɛ* in particular. We found that LUE models could …

Croplands cover 12% of the ice-free land surface and play an important role in the global
carbon cycle. Light use efficiency (LUE) models have often been employed to estimate the
exchange of CO2 between croplands and the atmosphere. A key parameter in these models
is the maximum light use efficiency (ε*), but estimates of ε* vary by at least a factor 2. Here
we used 12 agricultural eddy-flux measurement sites in North America and Europe to
constrain LUE models in general and ε* in particular. We found that LUE models could …