Redox reactions and their influence on the nutrient availability of plants

Redox reactions are critical processes in soil systems, influencing nutrient availability, microbial activity, and overall soil health. This chapter explores the intricate dynamics of redox reactions and their pivotal role in shaping the nutrient environment for plants. Redox potential (Eh) governs the oxidation and reduction of key nutrients, including nitrogen, phosphorus, sulfur, and micronutrients like iron, manganese, zinc, and copper. Under aerobic conditions, oxidized forms of nutrients are more stable, whereas anaerobic conditions enhance their solubility, often through microbial mediation. For example, nitrogen undergoes transformations such as nitrification and denitrification, while phosphorus availability fluctuates due to iron and aluminum redox dynamics. Microbial communities play a significant role in nutrient cycling by driving key redox-dependent processes, such as sulfur oxidation and phosphorus mobilization, often facilitated by root exudates. Redox fluctuations also impact heavy metal mobility, raising concerns about toxicity and environmental contamination. Agricultural practices, including water management, organic amendments, and precision irrigation, influence soil redox conditions and nutrient dynamics. Advanced monitoring tools, such as real-time Eh sensors and redox-sensitive dyes, provide innovative approaches for managing soil health and nutrient efficiency. The chapter emphasizes the environmental and agronomic implications of redox processes, presenting case studies on nutrient deficiencies in waterlogged soils and urban environments. Future research directions include integrating biomolecular tools, standardizing measurement protocols, and exploring under-researched elements like phosphorus. By understanding and optimizing redox reactions, this knowledge supports sustainable agricultural practices and enhances soil fertility.