Although you might not see them, there are a multitude of tiny critters in your lawn. The soil food web starts with the sun, travels through plants into the ground, passes through numerous soil-dwelling organisms, and continues up through larger predators such as humans.
Plants convert water and carbon dioxide into plant material via photosynthesis, and decomposers (fungi and bacteria) digest fallen leaves and other organic matter. Secondary consumers, such as mites and nematodes, feed on the fungi and bacteria, releasing nutrients that can be absorbed by the plants and contributing to the soil’s organic matter. They are then eaten by higher level predators, such as earthworms and ants. The larger predators release nutrients through waste that spur plant growth.
The diversity and abundance of the soil food web that contains these tiny critters is highly dependent on the organic matter content of your lawn.
Fertilizer and its associated salts cause mortality in soil organisms and decrease the overall organic matter content of the soil. Less soil organic matter disrupts and impairs the soil food web, which is detrimental to your lawn. A fully-functioning and robust soil food web is essential to fertile soil and a healthy lawn.