Acid Rain Formation and Its Direct Impacts on Plants: Wheat and Rice

Abstract

Acid rain is a serious environmental problem that occurs in many places around the world. Acid deposition can form as a result of the oxidation of sulfur dioxide and nitrogen oxide gases that are released into the atmosphere. These gases (SO2, NOx) are the primary causes of acid rain, and physically and chemically react with water, oxygen, and other chemicals to form other acidic compounds such as sulfuric acid (H2SO4) and nitric acid (HNO3). Acid rain can form in the presence of ozone and carbon dioxide as well. Sulfuric acid (H2SO4) and nitric acid (HNO3) affect biological systems like plants directly. This paper provides information about acid formation and the direct impacts of acid rain on plants. Through a survey of the literature, we assessed the direct effects of acid rain on leaf chlorophyll, growth, and yield parameters on crops that have the highest economic importance in Afghanistan. (e.g., wheat, rice). For the analysis of the data, linear regression was applied. The results showed that plant parameters (dependent variables) such as leaf length, leaf area, chlorophyll content, leaf dry weight, and weight of 1000 seeds of wheat; leaf area; net-photosynthetic rate; and leaf dry weight of rice can be significantly affected by pH treatments (pH 5.5–2.5) (independent variables). The trends of the analysis determined significant negative effects of acid rain on plant parameters. To reduce the impacts of acid rain on plants, it is necessary to apply adaptation and mitigation strategies.