The significance of the nitrogen cycle in agriculture lies in its role in maintaining soil fertility and plant growth. Nitrogen is essential for synthesizing proteins and nucleic acids in plants. The nitrogen cycle involves processes such as nitrogen fixation, nitrification, and denitrification, which convert atmospheric nitrogen into forms usable by plants, and then back to atmospheric nitrogen. Proper management of the nitrogen cycle is crucial in agricultural practices to enhance crop yield while minimizing environmental pollutants, ensuring sustainable food production and ecosystem health.