Quantifying the effects of aerosols and cloud radiative effect on rice growth and yield

Abstract

Radiative Effect (RE) caused by aerosols and clouds significantly impacts crop growth by altering both the spectral distribution and the amount of diffuse light reaching the crop canopy. Traditional crop models often fail to account for these variations in photosynthetically active radiation (PAR), leading to biases in crop growth simulations. To address this, we modified the ORYZA2000 crop model to improve the accuracy of radiation assessment. Using the RTM LibRadtran, we evaluated the effects of aerosol and cloud RE on rice growth and yield, utilizing data from Jiangxi Province, China (2011–2016). The results indicated that aerosols scatter PAR more effectively, with a scatter intensity 1.42 times greater than that of Shortwave Radiation (SW). Clouds increased the ratio of PAR in SW (FPAR) from 0.437 ± 0.01 to 0.448 ± 0.01. Ignoring PAR assessment in the crop model led to a 25.55 % overestimation of rice yield. When accounting for the diffuse fraction of PAR (PARDF) and FPAR, aerosol direct radiative effect (ADRE) increased rice yield by 18.58 %, cloud radiative effect (CRE) decreased yields by 16.13 %, and combined aerosol and cloud radiative effect (ACRE) resulted in a 31.71 % decrease in yields. Although aerosols alone increased yield by enhancing diffuse PAR, the combined effect of clouds and aerosols resulted in a lower overall PAR and caused a greater reduction in yield than clouds alone. Early rice exhibited more sensitivity to RE, allocating more biomass to the panicle in the early stages, while late rice increased leaf biomass during late stages under RE. This study underscores the importance of accurate PAR estimation in crop modeling and highlights the need to integrate the diverse impacts of RE into future crop yield predictions.