Potassium (K) is essential for plant growth and vital for soil health. However, despite high crop demand, K fertilization continues to be ignored or severely inadequate in Indian agriculture. Over time, this could lead to severe depletion of soil K reserve, irreversibly alter K-bearing minerals, and adversely affect soil fertility and crop productivity. Hence, we should comprehensively assess the alarming situation of soil K mining in India and come up with appropriate solutions. Keeping the above in mind, here we review the soil K pools concerning plant availability, their contents in major soil orders of India, reasons and status of soil K mining under major crops and cropping systems in India, and the impact of long-term K mining on soil K pools and clay minerals. We also address various aspects of sustainable K management in agriculture and suggest future action courses focusing on India. Our main findings are: (i) farmers in India mainly apply nitrogen and phosphorus, but little or no K; consequently, (ii) net K balance continues to be negative for most crops and cropping systems across India (e.g., -3.29 million tonnes [Mt] in 2000-01, -7.2 Mt in 2015-16); (iii) long-term K mining primarily depletes the exchangeable and non-exchangeable K pools in soil, and alters clay minerals to various extents; and (iv) the existing K fertilizer recommendations need an upward revision. We further enlist indigenous non-conventional alternatives of K fertilizers to meet the agricultural K demand. This is the first comprehensive review to simultaneously address the ongoing soil K mining in India, its impact, and its potential mitigation strategies. The points raised here would help reduce soil K mining, plan research work, and make policy decisions on K fertilization and residue management with the ultimate goal to prevent soil health deterioration and ensure sustainable crop production.
