At the heart of soil health

Authors: Lehman, R - Michael

Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 5/3/2017
Publication Date: 6/1/2017
Citation: Lehman, R.M. 2017. At the heart of soil health. Farm Journal, June 2017.

Interpretive Summary:

Technical Abstract: Soil health is receiving resurgent attention with a number of recent national soil health initiatives which are sponsored by cooperators from diverse sectors including agribusiness, commodity groups, governmental organizations, and non-profits. The health of the soil is dependent on its biology. At the heart of soil biology are soil microorganisms – the microscopic organisms that dominate the soil with their numbers and diversity. Soil organic matter is the foundation for a robust and diverse soil microbial community that serves as a healthy soil’s heart. Fortunately, there are many management tactics that have been shown to increase soil organic matter such as reduced tillage, elimination of seasonal or annual fallow using cover crops or perennials, retention of crop residues, and diverse crop rotations. Depending on the type and location of your operation, there should be one or more tactics that can be used to build the soil organic matter foundation for a flourishing soil microbial community. Most commonly, the combination of organic matter-building practices will result in the greatest gains in soil organic matter, an example of synergy in complex systems. It is equally important to provide a diverse and consistent input of organic materials by providing year-around vegetation that leaks a variety of plant-synthesized organics like sugars into the soils to support soil microorganisms. The organic inputs from living plants are then augmented by their residues when the plants senesce. A strong foundation of soil organic matter with consistent and diverse inputs will support a diverse soil microbial community that maintains an elevated, but relatively stable level of activity. Sustained levels of microbial activity are important to produce a steady supply of plant-available nutrients during the growing season and reduce their loss from the system. Maintenance of a diverse microbial community increases the levels of pest and pathogen protection provided by native soil microorganisms to the plants. Practices like no-till, cover cropping, rotation, and judicious use of fertilizations can promote a robust soil microbial community that maintains a high, but relatively even level of activity of the year fueled by soil organic carbon, plant exudates and plant residues. A steady, slightly elevated level of activity turns over soil organic matter and mineralizes nutrients in concert with the remainder of carbon and nutrient cycling in the soils, making nutrients available to plants at a rate that doesn’t promote their loss from the system. Management practices that improve soil health result in favorable levels of microbial activities which results in improved soil properties like the formation of stable soil aggregates. In turn, improved soil aggregation will promote microbial activities by permitting air and water to move through the soil. So improvements in soil health promote further improvement in soil health, just like improving your own heart’s condition by regular exercise promotes your ability to maintain the fitness of the rest of your body. So, if you are interested in improving soil health on your land, simply incorporate as many soil-building practices as your operations allow, and minimize use of practices that degrade soil. And, as importantly, continue to do so each year. Remember, building soil health is like building human health, it’s a lifestyle choice that requires life-long commitment.