Assessing energy balance closure over maize canopy using multiport system and canopy net storage

It is documented that measurements of CO₂ and H₂O concentrations using eddy covariance measurements from a single point height proved that the computed storage term for short ecosystems like agricultural crops is expected to be small as compared to the large ecosystems, e.g., forest. Large scale maize cultivation studies reported that storage term computation using a single height has some inaccurate estimations during turbulent periods. The role of canopy storage as result of inside canopy CO₂ and H₂O concentration is very small in the estimation of energy balance closure of crops by default single point method. Therefore, it is important to account for storage terms (CO₂ and H₂O) whenever CO₂ and H₂O fluxes are under consideration to study the energy balance closure. We developed a novel multiport system having four points profile and deployed in rural Philadelphia Tennessee to estimate the energy balance closure over a 22.6 ha maize field. The 15 min average data from the multiport system have been used to evaluate whether storage terms have enhanced or reduced the effects on the energy balance closure of the maize. In this study, we are also investigating soil heat storage along with heat storage by water contents and maize biomass. Our results showed that when the canopy storage term was considered, the overall 1:1 slope between partitioned fluxes (storage, ground, latent, and sensible) and net radiation increased by 2%, and r² value increased by 0.03 as compared to without considering canopy storage. Furthermore, it was recorded that the increase in the overall storage term was due to maize biomass water contents instead of air water contents.