Chemical fertilizers add nutrients to the soil, but they don’t add anything else. Plants needs more than just nutrients to survive. They also need organic matter and living organisms. Synthetic fertilizers do not support microbiological life in the soil. The application of a synthetic fertilizer actually kills a significant percentage of beneficial microorganisms. These tiny creatures are responsible for breaking down organic matter into a stable amendment for improving soil quality and fertility. Some convert nitrogen from the air into a plant useable form.