How do soil organisms contribute to the well-being of turfgrass?

• A. They improve soil texture by physical action.
• B. They immobilize nutrients preventing uptake.
• C. They break down organic matter, making nutrients available for absorption by turf roots.
• D. They produce toxic compounds harming roots.

Answer: (C)

Soil organisms support turfgrass health mainly by breaking down organic matter and turning it into nutrients the roots can absorb. Microbes like bacteria and fungi decompose plant residues, composted organic matter, and root exudates. As they digest this material, they mineralize nutrients—releasing forms such as nitrate and ammonium for nitrogen, as well as phosphorus, potassium, sulfur, and other micronutrients—that turf roots can take up. This ongoing nutrient cycling helps the grass grow vigorously, maintain color, and recover from wear or stress.

In addition, beneficial partnerships enhance this effect. Mycorrhizal fungi intimately associate with turf roots, expanding the effective root surface area and improving access to water and nutrients. Earthworms and other soil engineers mix and aerate the soil, boosting root growth and overall soil health, which further supports nutrient uptake and resilience.

While immobilization can occur temporarily—microbes may hold onto nutrients during decomposition—this is usually a short-term effect and, overall, the nutrient supply to roots improves as mineralization proceeds. Conversely, producing toxic compounds that harm roots is not a typical or desirable contribution of soil organisms to turf health.