Soil Acidification and its Impact on Plants

Abstract

Acidic soils are widespread covering nearly 40% of the world’s total arable land area. However, soils of certain regions are naturally acidic but an increase in soil acidification as a result of accelerating anthropogenic activities is becoming a global issue. High emissions of acid precursors (nitrogen, sulfur, and carbon dioxide) in the atmosphere are chiefly responsible for acid precipitation, which in turn is a pre-eminent factor for soil acidification. Long-term application of nitrogen fertilizers is a major contributor in acidification of agricultural soil. Soil acidification is an important edaphic stress, which leads to cation leaching, instability in the soil aggregate structure, increases metal toxicity, lowers the soil nutrient availability, and consequently affects the soil biological properties and plant performances. The present chapter aimed to assess the consequent effects of soil acidification on plants and the plant community structure. It includes causes, processes, plants’ responses, and remedial measures to combat soil acidification due to increasing pollution. Different plants may show different sensitivity to acidity and have diverse an optimal pH range for nutrient uptake. Besides, depletion of basic cations (Na, Ca, Mg, and K) due to leaching and increased solubility of toxic metals (Al and Mn) in soil restrict the plant’s access to water and nutrients, thereby causing severe injury to roots, a reduction in crop yield, and an increase in plant susceptibility to pathogens. Plant diversity, species richness, and occurrence of species are significantly influenced by acidification of soil. Alteration in the plant community structure, in turn, may affect the ecosystem structure and functions. Acidification of soil could plausibly be ameliorated by nutrient management practices and by addition of acid-neutralizing substances.