EVALUATIONS OF DIFFERENT LEAF AND CANOPY PHOTOSYNTHESIS MODELS: A CASE STUDY WITH BLACK LOCUST (ROBINIA PSEUDOACACIA) PLANTATIONS ON A LOESS PLATEAU

To evaluate the applicability of leaf and canopy photosynthesis models, we compared performance of 6 leaf models and validated 1 canopy model of photosynthesis based on field data of black locust (Robinia pseudoacacia L.) plantations on a Loess Plateau in northern China. Leaf photosynthetic light response curves and diurnal canopy photosynthetic rates were observed in the field in August 2009. Leaf photosynthesis was then fitted with Non-rectangular hyperbolic model, Rectangular hyperbolic model, Bassman exponential model, Prado exponential model, Binomial regression model, and Rectangular hyperbolic correction model, and canopy photosynthesis was fitted with an atmosphere-vegetation 2 way interaction model (AVIM). At the leaf scale, the different photosynthesis models demonstrated significant differences in calculating photosynthetic parameters of black locusts, and the Rectangular hyperbolic correction model performed better compared to other models, the limitations and merits of leaf photosynthesis models are also discussed. At the canopy scale, the AVIM model can well simulate the canopy photosynthesis for black locusts on the Loess Plateau. Although this is a case study, our findings may help to better understand the fitting capacity and applicability of these leaf and/or canopy photosynthesis models.