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Fatty acid levels = healthy soils
With his Ph.D. in plant science and a long history spent soil-testing with the government and private companies, when Ray Ward speaks about building up soil capacity, people listen.
Ward is still involved with soil testing. In 1983, he and his wife, Jolene, established Ward Laboratories in Kearney, Nebraska, which analyzed 263,000 soil samples and an additional 66,000 samples of livestock feed, forage plants, water, and manure. In his spare time, Ward manages the family farm located near Western, Nebraska.
“There’s a relatively new emphasis in soil testing,” Ward says. “We’re beginning to use the term soil health. Now, we look for more than just the chemical analysis of nutrients like nitrogen, phosphorus, potassium, and trace elements. Soil health can be defined as the soil’s ability to thrive as a living system, while sustaining healthy plant, animal, and human populations.
“Soil is our most important agricultural resource. It’s an ecological system composed of inorganic minerals, particulate substrates, organic compounds, and living organisms. Healthy soil has numerous species of bacteria, fungi, protozoa, algae, and earthworms – few of which thrive in tilled soil,” says Ward, who is also a no-till consultant to farmers.
Testing soil for fatty acid levels
A relatively new soil-testing technique is the analysis of fatty acid levels in soils, Ward says. “Fatty acids are components of living organisms, and the test can be used to estimate the total living microbial biomass in fresh soils. Microorganisms produce an organic glue that aids in the formation of soil structure. Organic matter also stores nutrients that can’t be directly absorbed by plants. Microbes consume organic matter as a carbon source and make the nitrogen therein available to plants. Organic matter is probably the most important component of soils and indicator of soil health,” he says.
Ward explains that tillage causes an influx of oxygen, which leads to the rapid breakdown of organic matter.
“Although there’s a short-term increase in fertility, it will quickly drop,” Ward acknowledges. “The slower breakdown of organic matter with no-till is ultimately more beneficial.”
Building up organic matter is one of the huge benefits of cover crops, Ward says. Cover plants add diversity to what’s become a monoculture; they also absorb nutrients and release them during decomposition. Their residues reduce soil and wind erosion, inhibit soil moisture evaporation, and improve water retention, all of which contribute to overall soil health.
“I’m an advocate of using a mixture of cover crops,” Ward says. “I call it a cocktail mixture of grasses and broadleafs, such as pearl millet, sudan, oats, buckwheat, turnips, milo, sunflowers, flax, and spring peas. When you plant a mixture of cover crops, the seed depth is set for the larger seeds. When they sprout, the ground is cracked, allowing the smaller seedlings to emerge. Such a cover crop mix would be used, for instance, in a five-year crop rotation of corn-corn-soybeans-wheat (a cover crop planted into the wheat stubble)-beans.”
Cover crop stories
Ward points out the cropping plan used by Robin and Kelly Griffeth of Jewell, Nebraska, who double-crop sunflowers in wheat stubble. At the same time, the Griffeths plant a companion crop mix of buckwheat, cow peas, common or hairy vetch, red clover, and millet.
“Another good example for cover crop experience as well as seed is the Berns brothers of Bladen, Nebraska,” Ward says.
“One of the advantages of a cover crop mixture is that it doesn’t require as much water as an individual cover crop, and the mix will produce more forage,” he explains. “It’s an interesting phenomenon. We’re not sure why this is the case. Cover crops also provide excellent grazing. We really need to add something new to the corn and bean rotation in the Corn Belt.”