JoAnne Skelly: Soil is a living thing

Often, gardeners focus on the plants in their landscape. However, successful plants rely on healthy soils to support them; hence, the old saying “Feed the soil, not the plant.” In Northern Nevada, soils are extremely variable and often challenge the gardener. Learning more about soil and about improving it, will help you develop a beautiful and productive garden or landscape.

A good soil is alive. Healthy soils are full of living creatures, such as earthworms, insects, mites and other arthropods (insects, spiders, crustaceans), nematodes, and microscopic plants and animals including fungi and bacteria. Together these living creatures are called the soil biota.

Soil biota play an important role in infiltration, water-holding capacity, pollutant processing, nutrient retention, nutrient cycling and plant growth. Soil biota contribute to soil productivity and fertility. They transform and cycle carbon, nitrogen and other mineral nutrients in plant and animal residues into forms that can be used by plants. Soil bacteria in particular have a wide range of abilities to break down pollutants into less harmful components, purifying water as it moves through the soil. Soil microbes secrete sticky substances that help organic matter and clay particles bind together to make soil aggregates, which create pore spaces for retention and exchange of air and water. Beneficial soil organisms suppress plant disease organisms allowing plants to thrive.

The population of soil biota is directly related to the amount of organic material in the soil. Low soil organic matter content reduces the biological component of the soil. Compaction reduces pore space, decreasing the habitat available for soil biota. Maintaining or improving the porosity and organic matter content of a soil helps to provide a good home for soil organisms. Otherwise, as the number of living organisms in a soil decreases, soil fertility also decreases, limiting plant growth.

Many Nevada soils are low in organic matter. Increasing the organic matter content of a soil, increases the water- and nutrient-holding capacity, improves the porosity and permeability and increases the likelihood of adequate soil biota. Using composted organic material will limit the introduction of undesirable insects, weeds and diseases into the soil.

For more information on soils go to the University of Nevada Cooperative Extension website www.unce.unr.edu/publications.

Just a reminder, January is National Radon Action Month. Radon is a naturally occurring radioactive gas that raises the risk of lung cancer. For a radon test kit, contact your local Cooperative Extension office or go to www.RadonNV.com.

JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at skellyj@unce.unr.edu.