SOIL ORGANIC MATTER AND NUTRIENT CYCLING IN AGRICULTURAL SYSTEMS: MECHANISMS AND MANAGEMENT PERSPECTIVES

Abstract

Soil organic matter (SOM) is pivotal for maintaining soil fertility and agricultural productivity by governing the nutrient cycling processes crucial for plant growth. Comprising various organic components, from new plant debris to extensively decomposed humic materials, soil organic matter (SOM) affects the behavior of macro- and micronutrients via processes such as mineralization, immobilization, complexation, and sorption. These mechanisms regulate the availability, movement, and retention of essential nutrients such as nitrogen (N), phosphorus (P), sulfur (S), and potassium (K) within the soil matrix. Furthermore, soil organic matter (SOM) augments cation exchange, regulates pH variation, and fortifies soil structure, thus enhancing the ability of soil to retain nutrients and moisture. This review examines the composition and classification of soil organic matter (SOM), its biochemical interactions with nutrients, and the microbiological and physicochemical mechanisms that facilitate SOM-mediated nutrient cycling. It further investigates the impact of agricultural practices, such as cultivation, crop rotation, residue management, and organic amendments, on soil organic matter dynamics and, subsequently, nutrient availability. Conventional techniques may hasten SOM depletion and disrupt nutrient cycling efficiency, whereas conservation-oriented approaches present effective solutions for increasing SOM levels and maintaining nutrient balance. This review emphasizes novel management strategies, such as integrated nutrient management, biochar application, and precision farming techniques, designed to sustain soil organic matter and enhance nutrient-use efficiency. This review emphasizes the significance of SOM-centered techniques in augmenting soil fertility, bolstering agroecosystem resilience, and facilitating sustainable agricultural intensification through the synthesis of current evidence.