SOIL ORGANIC MATTER AND NUTRIENT CYCLING IN AGRICULTURE: MECHANISMS AND MANAGEMENT

Abstract

Soil organic matter (SOM) plays a vital role in maintaining soil fertility and supporting nutrient cycling essential for plant growth. Through processes like mineralization, immobilization, complexation, and sorption, SOM regulates the availability and retention of key nutrients such as nitrogen, phosphorus, sulfur, and potassium. It also enhances cation exchange capacity, buffers pH, and improves soil structure and moisture retention. This review explores the composition, classification, and nutrient interactions of SOM, along with the microbiological and physicochemical mechanisms driving SOM-mediated nutrient cycling. It also examines how agricultural practices—such as crop rotation, residue management, and organic amendments—affect SOM dynamics. While conventional practices can deplete SOM and disrupt nutrient cycles, conservation strategies like integrated nutrient management, biochar application, and precision farming can sustain SOM and improve nutrient-use efficiency. Overall, SOM-centered management is key to enhancing soil fertility, promoting agroecosystem resilience, and advancing sustainable agriculture.