Estimating the light conversion efficiency by sugarcane: the segmented approach

Abstract

The classical method to estimate the light conversion effi ciency (ε c ) gives a single value for the whole crop cycle (ε co ) but does not reveal any variation along the growing season. We proposed the segmented approach to uncover such variations along sugarcane (Saccharum sp. hybrid) growth cycle. Our analyses revealed that longer sampling intervals could overestimate ε co and that the segmented light conversion effi ciency (ε cs ) varied between 0.09 and 5.39 g MJ -1 during the crop cycle. The ε cs would provide insights on how the environment affects ε c and how to increase biomass production through crop management practices.

Evidence of photosynthetic acclimation to self-shading in sugarcane canopies

“…In theory, about 6% of global solar radiation is converted into biomass by C4 plants (Zhu et al 2008), determining crop growth and yield (Lawlor 1995, Long et al 2006, Marchiori et al 2010. Light conversion efficiency in sugarcane may reach ~ 5.39 g MJ -1 (Cruz et al 2021(Cruz et al , 2022, and such efficiency is driven by canopy photosynthesis and respiration, with high photosynthetic rates and low respiration (mainly maintenance respiration) enhancing biomass production (Zhu et al 2010). Light interception efficiency is determined by the speed of canopy development, light absorption by leaves, longevity, size, and architecture of the canopy (Zhu et al 2010, Davey et al 2017, and is dependent on genotype and planting density (Robertson et al 1996, Tejera et al 2007.…”