By Todd Lorenz

In production agriculture, soil health can be broadly defined as the ability of the soil to perform to its agronomic potential. For hundreds of years, many societies failed to consider soil as the foundation of an environmentally sound sustainable web of life. Ignoring the essential roles of millions of species of soil organisms (fungus, algae, bacteria, nematodes, earthworms, etc.) was another critical oversight in understanding soil as a living, breathing organism. While physical properties and chemical nutrients were extensively studied, little consideration was given to the soil biological component until most recently.

The introduction of chemical fertilizers following World War II and the subsequent replacement of draft animals by mechanization, followed by synthetic pesticides, provided major changes in U.S. production management strategies.

Eventually, crop diversity was replaced by monocultures or short-term crop rotations for temporary improved economic gain. This change in management strategies provided considerable neglect to soil biological impact, reductions in soil health potential and the subsequent negative long-term legacy effect.

Studying soil health
Soil health research and understanding continues to improve through scientific interest and newer methodologies and technologies. Now management strategies should focus on the benefits of utilizing new soil tillage and crop management practices, such as cover crops, specifically designed to more closely imitate natural ecosystems.

The resulting effect has shown reduced need for herbicides, pesticides and fertilizers, thus reducing farming costs while improving environmental quality. The scientific challenge is quantifying the impact of various management decisions and their impact on building soil health potential.

Studies like the one from USDA Agriculture Research Service (see below), indicated that soil health potential is a continuum, which improves with
• perennial vegetation including grasses and legumes
• reduced tillage and soil disturbance
• incorporation of livestock grazing and manure into the system
• increased rotation diversity, including cash crops and forages
• cover crops for increased soil cover and diversity of the microbial population.

In the battle of perennial vs. annual systems, soil with cover over the years appears to be healthier than those without. This chart shows the continuum of soil health in various systems as researched by Kristen Veum, an ARS soil scientist.

Using all of these options for improving soil health may not be practical in every management scenario. However, implementing some of these considerations in an integrated and diversified systems-management approach will likely improve soil health potential and benefit production agricultural overall. Predicting soil performance requires a better understanding of the relationship between various soil properties and the potential for improved management decisions.

Change for the future
Research has confirmed that biologically diverse systems are much more resilient in the face of environmental stresses. Reliance upon current production system during times of increased weather variability, especially increased frequency and duration of drought, is a potential recipe for economic and environmental disaster.

Building soil health is a legacy that can be passed on through the generations. It is expected that along with the new interest in soil health, increased rigorous research will help guide producers in best management practices to improve our nation’s food security while increasing environmentally sustainable agriculture production for generations.

Lorenz is a MU Extension agronomy specialist, who writes from Booneville, Mo.