The negative effects of simulated acid rain on maize physiology, grain quality and yield in a field trial

Abstract

Acid rain is a global environmental problem that negatively impacts plant physiology and hinders crops growth and yield. However, most researches on acid rain have mainly focused on pot experiments, while in-situ research on maize is still rare. Therefore, this study conducted two-season field experiments to investigate the effects of three simulated acid rain treatments with three pH levels (2.0, 3.5 and 4.5) on maize growth compared with control (pH_6.0). The results showed that simulated acid rain inhibited the growth and yield of maize. At pH_2.5, the plant height and stem diameter of maize decreased by 8.55% and 11.49%, and the leaves were irregularly damaged. Under pH_2.5, actual photosynthetic efficiency decreased by 23.55%, the growth and development of plants were directly affected. As a result, maize yield decreased by 17.64% at pH_2.5. Moreover, at pH_4.5, fructose content in the kernels decreased by 16.95%, while the glucose content increased significantly by 79.22%. At pH_4.5, the activity of superoxide dismutase (SOD) increased by 37.63%. In summary, acid rain affected the physiological characteristics of maize, resulting in a decline in grain quality and yield. And maize could respond to acid rain stress by adjusting carbohydrate metabolism and enhancing antioxidant mechanisms. These findings depict the response of maize to acid rain and provide a reference for alleviating the impact on maize growth through sustainable agricultural practices in an acid rain environment.