HUMIC ACID: INSIGHTS ON MAXIMIZING CROP YIELD, NUTRIENT USE EFFICIENCY AND SUSTAINING SOIL HEALTH

Abstract

The increasing demand for food production and the decline in soil fertility highlight the need for sustainable strategies to improve the crop productivity while maintaining soil health. Humic acid (HA) is a complex organic material formed during the decomposition and transformation of plant, animal and microbial residues. Its diverse functional groups and biological activity enable HA to influence soil properties, nutrient dynamics and plant growth. This review provides insights into the role of HA in maximizing crop yield, improving nutrient use efficiency (NUE), and sustaining soil health. The sources, formation, extraction protocols are discussed. Particular emphasis is given to its influence on soil physical, chemical and biological properties, including aggregation, water retention, cation exchange capacity, nutrient availability and microbial activity. The potential of HA to improve nitrogen, phosphorus and potassium use efficiency through enhanced nutrient retention, reduced losses, improved root development and nutrient uptake is also examined. Its effects on crop growth, yield and quality and its potential for mitigating soil degradation are summarized. However, HA effectiveness varies with its source, composition, application rate, formulation, soil properties, crop and environmental conditions. Therefore, standardization of HA products, optimized application strategies and long-term field evaluation are required. Overall, HA offers a promising approach for integrating crop productivity, efficient nutrient management and sustainable soil health.