Gas exchange and growth/decline model of C3 turfgrass fields under various light conditions

Abstract We developed a predictive model based on the mechanisms of photosynthesis and growth/decline in C 3 turfgrass, which has applications for turfgrass management plans over a wide range of environments, including shaded growth conditions, such as turfed football stadiums. The numerical formulas, algorithms, and parameters for defining photosynthesis and the growth/decline in a turfgrass community are presented. The parameters that were optimized to simulate photosynthesis and growth/decline were included in the multilayer model for gas exchange and the vegetation growth/decline model. The model was validated using data collected on leaf biomass, root biomass, leaf area index, cumulative mowing, cumulative root growth, and litter (leaf and root) over a 2-year period in a stadium in which Japanese Professional Football League games are played. We also developed an algorithm to simulate and map the growth conditions in two dimensions. To fit the simulated and observed data better, we varied the parameters by season and irradiance conditions. The results showed that changes in leaf and root biomass over intervals that were less than annual affected gas exchange and the balance between respiration and assimilation rates and, in turn, caused changes in leaf and root biomass.