Potassium-solubilising bacteria: A sustainable approach for enhancing global potassium nutrition in agriculture

Potassium (K) is the third most essential macronutrient after nitrogen and phosphorus. It is vital for plant metabolism, yield, and stress tolerance. In India, the absence of indigenous potash reserves and a heavy reliance on expensive imports have resulted in significant potassium depletion in soils. Additionally, the high cost of potash fertilizers discourages farmers from applying the necessary amounts, leading to nutrient deficiency. This paper provides a comprehensive overview of potassium dynamics in soil, current constraints on potash fertilizers in India, and the global potash market situation. It also highlights the role and mechanisms of potassium-solubilising bacteria (KSB) in transforming insoluble mineral potassium into plant-available forms through processes such as organic acid production, chelation, and enzymatic action. The paper stresses the importance of incorporating KSB as a biofertilizer to improve nutrient-use efficiency, enhance soil fertility, and promote sustainable crop production. Future prospects include developing effective microbial consortia, standardising field applications, and utilising genomics-based approaches for large-scale use of KSB, aiming to reduce dependency on potash fertilizers and encourage sustainable agriculture.