Soil Armor
Soil Health Principle Descriptions by Jay Fuhrer, Menoken Farm Conservationist
Principle 1
Agriculture has a long history of bare soils, even contributing to the downfall of past civilizations. Bare soils come with several challenges, such as prone to wind and water erosion, temperature extremes, moisture extremes, rainfall compaction, salinity, and many times reflect the losing end of the carbon cycle. The soils we enjoy today were not built by this management type. Instead, our soils were primarily built over geological time by perennial grasslands and forests, along with microbes, ruminant animals, and predators, while throwing in an occasional glacier and volcano. Soils are the interface of the Atmosphere (soil air), Biosphere (organic matter and biomass), Lithosphere (soil particles), and the Hydrosphere (soil water): The Nature and Properties of Soils - 14th Edition, page 11. The importance of soil cannot be overstated.
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Brown armor - Farms which moved into no-till systems started leaving crop residue or brown litter on the soil surface, usually from a recently completed harvest. This management change moderated erosion, temperature, moisture loss, compaction and even salinity. The soil microbes could now adjust back to something they were used to, residue on the soil surface. After a few years into the no-till system the microbes were usually adjusted, which meant they were no longer tying up nutrient for residue decomposition. For many farms soil cover or armor meant the soil could hydrate again and support more life.
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Green armor – Farms which provide green armor found as young green plants evolve, they emit carbon into the soil, so now we reflect the gaining end of the carbon cycle. Green cover crops can be provided in the spring or fall, and sometimes used as companion plantings. The same bare soil challenges addressed by brown armor, can also be addressed by green armor. When we combine brown and green armor together, we get the best of both worlds. For instance, brown is giving off carbon dioxide and green is taking in carbon dioxide. Brown feeds saprophytic fungi and green feeds mycorrhizal fungi. Combining a no-till system with green armor allowed us to limit the release of carbon dioxide from our soils while simultaneously maximizing carbon into our soils, a good combination as explained to the agricultural community by Dr. Don Reicosky, Retired Soil Scientist, ARS, Morris, Minnesota.
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We need to manage the bare soil challenges if our goal is soil health. Soil Armor is listed as the first Soil Health Principle for this reason. With cover on the soil as a foundation, we have now set the stage for additional soil health principles. How to achieve cover on our soil varies across the US from west to east and north to south. A good starting point is to write a description of what Soil Health Principle 1 – Soil Armor looks like on your landscape. Arid regions tend to use more brown armor, especially at the start of a new no-till system. Higher rainfall regions tend to use more brown and green armor. Both regions start to benefit from an increased ability to hold more soil water, a benefit from increased soil aggregates and carbon levels.
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Farmers, ranchers, and gardeners continually manage soil cover, using both brown and green armor. Soil Armor is not an easy process, as soil biology consumes more residue as it improves, creating the need for still more cover. Soil Armor should be evaluated by looking straight down at the soil surface and asking yourself, “What percent of the soil is protected by cover?” The goal is 100% soil cover with brown and/or green armor. Let’s armor up!
Featured Farm
Menoken Farm
1107 171st Street NE
Menoken, ND 58558
Farm Manager, Seth Boechler
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The Menoken Farm is an educational site consisting of 150 acres of cropland owned and operated by the Burleigh County Soil Conservation District, located just east of Bismarck, North Dakota. The indigenous language interprets Menoken as “you reap what you sow”. A very fitting name for a conservation demonstration farm. The Burleigh County Soil Health Team identified several resource concerns across the Northern Plains landscape after the 2009 initial startup. These included a lack of soil surface armor, minimal biological diversity, poor nutrient cycling, slow infiltration, collapsed soil aggregates, carbon deficient soils, and little beneficial insect habitat and food. The five Soil Health Principles were then set into motion to address the resource concerns.
Menoken Farm Manager, Seth Boechler, shared a few armor observations: “Armor is an important first step. You really can’t set the system into motion until this principle is applied. When I walk a cropland field the armor usually isn’t perfect, occasionally there are still some areas with little or even no cover. Providing armor is a continual process. The Menoken Farm surface residue amounts vary from field to field and when managed properly have not hindered successful seed soil contact. The armor benefits are obvious at the Menoken Farm during spring planting. The fields are well protected and stable, even during strong windstorms”.
The Menoken Farm uses all 5 Soil Health Principles in a systems approach, with Soil Armor as the first principle applied. A diverse plant community was used to cover the soil, both green plants and brown dead litter. Initial observations included the reduction and eventual elimination of erosion, followed by soil hydration. Cropland fields across the world struggle with forming enough armor to create an O (Organic) Horizon, which covers the soil surface and consists of decomposing dark plant material. O Horizons contain high amounts of organic matter and are nutrient rich. Bare soils have little to no O Horizon. Consequently, the crops are missing the soil fertility, temperature, and moisture management benefits provided by the various layers of decomposing organic material. Seth went on to say; “Wherever the armor is adequate you can physically see the life under the residue. The diversity of life varies within the residue decomposition stage, eventually creating a fertile, dark, well aggregated soil”. While the O Horizon is more prevalent in our prairies and forests, providing cropland armor helps mimic the original O Horizon benefits.
Going forward, let’s open our minds to what plants and microbes may achieve. Armor will continue to be important, both green and brown. The Menoken Farm has used various systems to cover the soil. Using green covers and/or brown dead litter during the spring window, summer companion window, and fall windows. Seth gave a few recent Menoken Farm examples: “Winter Wheat/Clover, Buckwheat/Alfalfa, Sunflower/Multi Species, Corn/Multi Species, and Soybean Planted Green/Mowed. These are used before, during, and after a cash crop whenever a window presents itself. We use annual, biennial, and perennial plants; and always move toward the elusive goal of no-tillage, and no pesticide use.”