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ARCF applications are now being accepted year round with projects being funded as funds become available.

Grow Life in the Soil

Grow Life in the Soil

The need is critical to grow more life in the soil, and it starts by treating it as you would your own body.

Raylene Nickel

Soil is filled with living, breathing, hardworking creatures – it’s a natural commodity more important than any cash crop. When soil is alive, it’s teaming with macro- and microorganisms, ranging the gamut from highly visible beetles and worms to microscopic viruses, bacteria, and fungi. Each of these soil citizens provides a service to the healthful functioning of the broader community.

Having lots of healthy and diverse organisms in the soil creates a self-sufficient cropping system that becomes less dependent upon synthetic fertilizers and pesticides.

The system itself produces fertility for robust plant growth, resistance to pests, and water-stable soil aggregates that enhance soil porosity to permit rapid water infiltration and to resist erosion.

In a nutshell, such a system produces resilient crops. In today’s uncertainty of climate, the need for plant resilience is growing more urgent by the day.

“The need to think about and work toward soil health is becoming extreme,” says Kris Nichols, a soil scientist-consultant from Kutztown, Pennsylvania. “Plants need resilience in order to withstand stressors such as adverse weather. One thing that you can count on is a continuing increase in the uncertainty and variability of climate.

“During the span of just one week here in Pennsylvania last winter, we had historic lows and historic highs in temperature,” she says. “We had a swing in temperature of 70°F. That doesn’t make any sense. Yet, it’s happened multiple times. How does a plant respond to such variability in conditions?

“We need a production system that is resilient,” she says. “A healthy soil that is alive with organisms keeps the system resilient. It does that by promoting diversity of life in the soil and above ground.”

Soil loss

Along with the growing need for resilience in cropping systems, there is a need for the kind of stable soil structure that resists wind and water erosion.

“We lose nearly 2 billion metric tons of topsoil annually in the U.S.,” says Nichols. “Most of that ends up in lakes, rivers, and estuaries. In the Gulf region, for instance, dredging is needed to remove the soil in order to keep shipping lanes open. Much of it is piled in that area, clogging the estuaries and exacerbating drainage problems.”

Eroding topsoil typically carries nitrates and phosphates from synthetic fertilizers with it, notes Nichols. These nitrates and phosphates end up in ground and surface waters, creating conditions such as the Dead Zone in the Gulf of Mexico.

“In some communities now in places such as the Midwest, it’s hard to get good drinking water without having to do costly filtration,” she says.

Limited supplies of phosphorus (P) fertilizers are yet another reason to build communities of healthy soil critters that can meet the plants’ need for P by extracting it from the soil and delivering it to plants.

“Globally, we’re running out of phosphorus fertilizer,” says Nichols. “Phosphorus fertilizer is mined and shipped into this country. A supply of about 20 to 30 years is about all we have left. Then we’ll have to figure out a different way to get it. Furthermore, when we apply it, much of it is wasted because, if it is not lost via erosion, it becomes readily unavailable in soil and can only be made available again by soil biology.”

These symbiotic relationships between plants and soil organisms permit natural pathways to fertility, disease resistance, soil stability, and whole-system resilience to weather variabilities.

All this while sidestepping much of the need for intervention with synthetic inputs.

When functioning in a healthful, whole-system framework, these relationships between plants and soil organisms, says Nichols, exist in an “elegantly complex” balance grounded in simple processes.

“We need to think about caring for the soil in the same manner that we take care of our own bodies,” she says.

With that in mind, following are the three cornerstones she suggests putting in place to grow life in the soil.

1. A healthy diet. “Carbon is the building block for every cell and every molecule for nearly all life on planet Earth,” she says. “Soil needs an influx of carbon through the process of photosynthesis occurring in living plants. It’s important to keep living plants growing in the soil.”

Diversity of diet is critical, too. “Feeding the soil a continuous diet of corn or wheat crops provides a lot of carbon, but it won’t be that healthy,” says Nichols. “Like us, the soil needs carbon in the form of protein or more complex carbohydrates. That’s why it’s important to have legumes and oilseeds in the system.

“All the different crops and crop types provide different compounds and different concentrations of these compounds for the soil life to eat,” she says. “Different consortia of different organisms consume different root exudates and crop residue from different plants.”

Growing diverse crops, cover crops, and perennials provides the soil life with the diverse diet needed to thrive and increase in population. Increasing diversity of cover crops can compensate for decreased diversity in cash crops.

2. Plenty of exercise. Providing the soil critters with work gives opportunity for exercise. “Their work involves breaking down and releasing nutrients in organic matter and minerals in the soil,” says Nichols. “In this process, they provide water and nutrients to the plants. Like us, they need a little bit of stress in order to best manage their food.”

A supply-and-demand payment system exists between plants and soil life. The application of synthetic fertilizers interferes with this delicate balance.

“Applying fertilizers outsources the work of the soil organisms,” says Nichols. “They buy carbon from the plant by giving the plant something.”

Outsourcing of their work happens, she says, when applications of synthetic fertilizers cause a lockdown in the plants’ natural mechanisms to work with soil organisms.

Thus, the soil organisms are bypassed, preventing them from having enough food to live on.

One example of this is roots that won’t allow arbuscular mycorrhizal fungi to colonize them.

3. A stable home. The soil organisms engineer for themselves homes in the soil known as soil aggregates. “The aggregates are like microbial villages, giving the fungi and bacteria a safe place to live,” says Nichols. "Tillage breaks apart the aggregates. It’s like taking a wrecking ball or a bomb and blowing up the village.”

The displaced organisms become more vulnerable to predatory organisms. “They were safe in their village, but now they’re exposed to larger organisms that eat them,” she says.

This predator/prey relationship is always going on in the soil, but the loss of soil aggregates permits an unhealthful balance of species.

Reducing tillage preserves habitat for the soil life, as does keeping the soil covered by residue or mulch.

“Even the impact of raindrops hitting the soil surface can blow up aggregates,” says Nichols.

Over the long term, growing life in the soil offers the priceless benefit of building a production system that is more resilient to wide swings in weather. Economic resilience could come hand in hand with healthier soil.

“You could expect to reduce costs, which could improve the bottom line,” says Nichols. “With a more resilient system, you could also expect to reduce year-to-year fluctuations in income.”

Alternative Forages: Specialist looks at different options

By Kylene Scott

Kansas State University’s Beef Systems Specialist Jaymelynn Farney is investigating how cattle choose what to eat.

Farney, who is at the Southeast Research and Extension Center in Columbus, Kansas, has been performing studies on what forages cattle prefer. She’s using summer cover crops, or annual forages, in re-purposed protein tubs. They’re then offered to cattle to determine preference.

“I have grown eight plant species in each growing period and offered the plants to the cows in two 24-hour sessions,” she said. “We recorded their behavior for the first hour after introduction to the plants and they were video recorded through the remainder of the time to see which plants they completely consumed and in which order.”

The study wants to help producers make decisions about which cover crops to plant when incorporating grazing.

“There is a laundry list of plants that contain useful cover crop benefits and it becomes daunting to select the species that will meet your operation’s objectives,” Farney said.

When deciding what plant species to sow, Farney said there are two trains of thought.

Purposefully plant only those species that cattle will consume to maximize land usage or gains along with capturing some cover crop benefits; or

Strategically plant species that cattle are averse to in order to leave appreciable biomass in the field for soil health objectives.

“With these two things in mind I was interested in seeing how cattle that were completely naive to cover crops consumed these plants,” Farney said.

Initially, Farney has found the most preferred plants include: Barley, Austrian winter pea and Graza forage radish (tie), mustard, Impact collard, Trophy rape, and purple top turnip (all fairly the same in preference). Last was Bayou kale. Her preference information was collected prior to a freeze.

“Stay tuned to next year to find out what their preference to these same species are when grazing after a killing freeze,” Farney said.

For summer grazing, in order from most preferred to least includes: Brown mid-rib forage sorghum and sorghum-Sudan (tied for first), pearl millet, Black oil sunflower and sun hemp (tied for third). Least favorite with little to no difference (strongly objected) were mungbean, okra and safflower.

Farney said there is some learning in both the cattle and the researchers associated with these summer grazing plants.

“The first day exposed nearly all the cows did not even try the okra, but the second day they consumed them before mungbean and safflower,” Farney said. “Another interesting comment about the summers, all grazing occurred when the sorghums were 2 feet tall to minimize prussic acid issues.”

For the sorghums, grazing occurred 35 days after planting. The sunflowers in that time frame were very small and immature (6 to 8 inches tall at the most) while the mungbean and okra had leaves that were over 7 inches in diameter.

“Preference studies become difficult to quantify as cattle do learn and modify grazing behavior especially after that first introduction to new plants,” she said.

When in drought

Farney suggests spending some time to determine the plant species with more drought tolerance.

“I would stay away from really expensive components of mixtures because there is a greater chance of crop failure with no moisture,” she said. “There is some literature that shows that a few different plant species as a cover crop have some environmental lee-way.”

For stocker cattle

Farney leans heavily on the grass component of a stocker cover crops plan.

She limits brassicas to a 1 pound per acre with maximum of 1.5 pounds of brassica seed per acre. Amounts over this can cause the brassicas to outcompete the grass species and reduce grass tonnage. For fall forages, the grass and brassica species offer enough protein to the animal.

“Younger calves have a stronger aversion to the broadleaves and brassicas than cows do and this can potentially hamper gains for a short duration until they begin to consume these plants,” Farney said

“In Kansas, from my research and measuring producers fields, we rarely get any fall growth of legumes,” she said. “This is an expensive component of the mixture and with the combination of low to no-growth and no need for additional protein to meet calf requirements, I do not include legumes in fall covers.”

Farney suggests oats and barley—both spring and winter varieties—to those looking to graze something other than native grass as they offer the earliest, quickest growth. Triticale is intermediate and wheat and rye will have the majority of their growth late winter and early spring. Turnips and radishes have a very rapid growth rate, but once a freeze happens, they don’t generate any more dry matter. Grass species continue to have some growth as the season goes on.