Marie Vicksta - The ground beneath your feet
“A nation that destroys its soil destroys itself.”
— President Franklin D. Roosevelt
After the crisis of the Dust Bowl in the 1930s, conservation of soil and water resources became a national priority. Our country recognized the massive economic, environmental and cultural impacts caused by poor farming practices. The catastrophe spurred the creation of the Federal Soil Conservation Service, now the Natural Resources Conservation Service (NRCS) as well as local soil and water conservation districts. These agencies were expected to educate landowners about building soil health and fertility, or tilth, thus preventing disasters like the Dust Bowl.
Since the Yamhill Soil & Water Conservation District’s beginnings in 1953, we’ve been educating people about the importance of healthy soil. The soil beneath your feet may appear static, but it’s actually dynamic, complex and full of life. Millions of species and billions of organisms make up a complex, diverse mix primarily composed of microscopic life.
Bacteria, algae, tiny insects, earthworms, beetles, ants, mites and fungi live in soil. Creatures in the soil represent the greatest concentration of biomass anywhere on the planet. Altogether, their value has been estimated at $1.5 trillion a year worldwide. They recycle nutrients, create the soil and give it structure. The healthiest soils are those containing the most diversity and quantity of life.
Like other living creatures, organisms in the soil need food and shelter. Some feed on dead organic matter; some eat other microbes. Keeping soil covered with living plants or plant residue throughout the year provides the necessary shelter.
A living plant maintains a rhizosphere, an area of concentrated microbial activity close to its roots. The rhizosphere, where the easiest-to-eat food is available for microbes, is the most active part of soil biology. It’s also critical for plant growth and health, because these microbes, in turn, make essential nutrients available for crops.
Providing good habitats for these organisms increases residue decomposition and improves nutrient abundance.
The most important component of soil health is organic matter, which links the biological, chemical and physical properties of soil. Organic matter stabilizes soil particles, improves soil tilth and increases the soil’s ability to infiltrate and store water, which reduces runoff and erosion.
Carbon in organic matter is the main source of energy for soil microbes and the key for making nutrients, such as nitrogen, available to plants. Cover crops, green manure crops and perennial forage crops add organic matter, as do compost and manure, which will be consumed and decomposed by microbes and create more fertile, nutrient-rich humus.
The NRCS’s Plant Materials Center in Corvallis is involved in a three-year national study considering the effects on soil health of various cover-crop mixes and seeding rates. Conservation Agronomist Annie Young-Mathews reported first-year results: using cover crops increased organic carbon levels, decreased soil compaction and yielded cooler, wetter soils — all components of healthier soils — compared to plots without cover crops.
In Burleigh County, N.D., farmers are taking cover cropping and managing for soil health to the next level. In test plots there, NRCS reviewed the results of cover crops with mixes of one, two, three and eight species planted before one of the driest seasons on record. They found the eight-species mix withstanding the extreme drought stress far better than the other species mixes or the single-species cover crop, which failed. Now, some of the farmers there are planting cover-crop mixes with up to 20 species, which will enhance the diversity of subsoil biosphere, improve drainage and reduce field inputs.
What can I do to keep my soils healthy?
To maximize soil health and minimize erosion, consider the following when managing your land or garden:
1. Manage more by disturbing less
Soil disturbance can result from physical, chemical and biological activities. Physical soil disturbance, such as tilling, creates a hostile, destructive and disruptive environment for soil microbes when it produces bare or compacted soil. All forms of soil disturbance reduce habitat for soil microbes and result in a diminished soil-food environment.
2. Diversify soil biota with plant diversity
An assortment of plant carbohydrates is required to support a greater diversity of soil microorganisms. In order to achieve a high level of diversity, different plants must be grown. The key to improving soil health is ensuring that food and energy webs consist of several types of plants or animals rather than just one or two.
3. Keep a living root growing throughout the year
Healthy soil is dependent upon how well the soil food-web is fed. Providing plenty of easily accessible food to soil microbes helps them cycle nutrients that plants need for growth. Sugars from living plant roots, recently dead plant roots, crop residues and organic matter all feed the many and varied members of the soil-food web.
4. Keep soil covered as much as possible
Cover, living or not, provides a multitude of benefits: moisture retention, lower soil temperatures, erosion prevention and weed suppression. It also adds to the organic matter of the soil.
Through good land stewardship, managing land for soil health and continued landowner education, the national tragedy of the Dust Bowl may never be repeated. For more information about soil health or building soil tilth, visit the district office at 2200 S.W. Second St., McMinn-ville. We can supply you with free educational literature, and our staff can offer free technical assistance to county residents on managing natural resources.
Guest writer Marie Vicksta is a conservation planner with the Yamhill Soil and Water Conservation District, where she has worked for four years. Her work is primarily establishing farm projects to improve water quality and reduce erosion. In her free time, she enjoys getting outdoors and working with friends in their gardens.
Courtesy of Natural Resource Conservation Service in Corvallis
In May 2013, cover crops including these radish, turnip, crimson clover, hairy vetch and cereal rye plants were growing in the community garden at Physicians Medical Center Cover in McMinnville.
Photo courtesy of Natural Resource Conservation Service in Corvallis
A tester uses a soil probe to collect a core sample. The Yamhill Soil & Water Conservation District educates landowners about building soil health.