Sustainable Nutrient Management in Calcareous Soils for Improved Nutrient Use Efficiency and Crop Productivity

Abstract

Calcareous soils occupy nearly one-third of the global land surface, predominantly in arid and semi-arid regions, and are characterised by high calcium carbonate (CaCO₃) content, alkaline pH, low organic matter, poor aggregate stability, and multiple nutrient-related constraints that limit crop productivity. High CaCO₃ concentrations strongly influence nutrient dynamics through fixation, precipitation, adsorption, and volatilisation processes, thereby reducing the availability and use efficiency of both macronutrients and micronutrients. Major constraints include nitrogen losses through ammonia volatilisation, phosphorus fixation as calcium phosphates, potassium imbalance, sulfur deficiency, and deficiencies of zinc, iron, boron, manganese, and copper. Poor physical properties, including soil crusting, hardpan formation, low infiltration, and restricted root growth, further reduce nutrient-use efficiency. The severity of these constraints varies with climate, soil mineralogy, cropping systems, irrigation practices, and management history, making nutrient deficiencies a major challenge in countries such as India, Pakistan, China, Egypt, Iran, and Australia. Sustainable management of calcareous soils requires integrated and site-specific nutrient management strategies rather than reliance on conventional fertiliser application alone. Recent advances show that combining inorganic fertilisers with organic amendments, biochar, compost, crop residues, microbial inoculants, conservation agriculture, foliar fertilisation, controlled-release fertilisers, and precision nutrient management can enhance nutrient availability, soil fertility, and crop productivity. Organic amendments improve soil organic carbon, aggregation, microbial activity, and nutrient buffering, while biochar enhances nutrient retention and water-use efficiency. Technologies such as site-specific nutrient management (SSNM), nano-fertilisers, and microbial-assisted nutrient mobilisation further improve nutrient-use efficiency under alkaline conditions. This review synthesises recent global research on the distribution, characteristics, nutrient dynamics, and sustainable management of calcareous soils, with emphasis on integrated nutrient management, climate-resilient technologies, and future research priorities for improving nutrient-use efficiency, soil health, and long-term agricultural sustainability.