Hardin County SCD

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Hardin Co. Soil & Water Conservation District

APPLY TODAY! DEADLINE FOR COVER CROPS IS AUG. 31st

. AECF Flyer

NRCS Dictrict Conservationist, Martha Griffin

Soil Conservation District Secretary, Elizabeth Gibbs

Office Hours are 8am - 3pm M-F

731-412-3106

NRCS/ Hardin County S&WCD

1035 C Wayne Road

Savannah, TN. 38372

Why should farms use cover crops?

Farmers across the country are looking at ways to boost soil health, manage crop nutrients and nutrient retention, and perhaps raise more feed for cattle. In each case, cover crops could play a valuable role. The idea of “farming green” isn’t new, with farmers using fall-seeded crops to hold soil in place for some time.

However, the planned use of cover crops can bring key benefits to soil fertility and water conservation. Yet getting started can be a challenge. With good management they can make a difference on the farm. In this section, you’ll find insight into their value including:

Protecting soil from erosion
Moderating soil and air temperature by shading the soil surface.
Preventing soil nutrient loss and increase soil carbon

Cover crops represent an effective in-field practice, and investment account, for the farm by protecting soil, extending the grazing season and reducing the need for stored forages. And they can be grown in any farming system.

Cover crop benefits

The list of benefits is longer than simply adding carbon to soil. In this section there’s a look at how the practice provides added value.

Organic farms have found they can suppress weeds, but it’s a benefit for conventional farms too. With the rise of resistant weeds, producers are finding a healthy fall cover crop can offer weed control in the following year crop.

Cover crops improve water quality. In one study in Michigan researchers found that on average they reduce sediment 1,840 pounds/acre from wind erosion and decrease sediment 340 pounds/acre from water erosion.

They can also boost fertility in some cases replacing a portion of applied nitrogen to the following crop. The same crop can boost soil microbes, earthworms and other organisms by boosting soil structure. And cover crops can help break up soil compaction.

Farmers using cover crops have seen a yield increase. In Kentucky, winter cover used with no-till planting showed a significant increase in corn yield. Similar results were found at Iowa State University.

Some types, such as tillage radishes, can “do the tillage for you” providing improved soil tilth and breaking up soil compaction. They can also facilitate drainage.

Winter cover crops can significantly reduce soil erosion with reductions reaching 50% when winter cover is available. Keeping soil on the farm is an investment in the future of the operation. There’s extensive work showing how impactful they are for reducing erosion.

Some species can be used to help restore storm damaged fields. And for many that’s part of a planned rotation of crops and cover crops that offer an added benefit. Tillage radish has been shown to offer a significant benefit, if it can be worked into the rotation.

Cover crops can also cut your nitrogen cost. In some cases, they can replace nitrogen applications, or at least supplement nitrogen for the crop. Given today’s fertilizer prices, figuring the cost of added nitrogen from cover crops helps pay for the practice.

They can also boost organic matter. Raising OM levels in a field offers other benefits from improved nutrient mineralization, better moisture retention and the opportunity for higher yields.

Using cover crops during drought

There’s a concern that cover crops might not be appropriate in drought conditions, yet these post-crop covers may have added benefits. For example, after the 2012 drought agronomists advised planting them to capture unused nitrogen before it leached below the tile zone.

They can also act as a moisture trap which may counter some who worry that the winter planting might reduce subsoil moisture further. Work in North Dakota has shown them to help conserve moisture, in part because they keep soil covered. Bare soil gives up more moisture than ground protected by a cover crop, researchers found.

Cover cropping plan

What’s the old sayin? Failure to plan is planning to fail. Adding cover crops to your farm’s planting program isn’t done lightly. The key to success is to work through the potential challenges before you engage the first field.

We ask some simple questions to help you determine the best approach to adding cover crops for your farm. From changing crop choices to add a little more fall establishment time to identifying the best fields for cover crop use.

This section also digs into the questions surrounding cover crop planting choices. A tillage radish may not be right for your farm, but what about annual ryegrass or cereal rye? And what is the difference between those two crops?

There are also “variety mixes” that may be priced lower. They offer both opportunities and challenges. Knowing the mix of seed in a variety cover crop can help you determine the best practices for burndown.

Cover crop guide to varieties

This section pulls together a wide list of cover crop choices available to farmers. While not all are best suited for every operation, this comprehensive guide provides added information about potential uses on the farm.

The list of varieties with a deeper look at their key benefits includes:

Grasses

Annual/Italian ryegrass
Reed Canarygrass
Birdsfoot Trefoil
Kentucky Bluegrass
Forage Chicory
Tall Fescue
Smooth Bromegrass
Barley
Proso Millet
German/Foxtail Millet
Pearl Millet
Oats
Rye/Cereal Rye Grain
Sorghum/Sudangrass
Teff
Triticale
Wheat

Legumes

Alfalfa
Austrian Winter Peas
Crimson Clover
Fava Bean
Berseem Clover
Field Peas
Hairy Vetch
Kura Clover
Medics
Mungbean
Red Clover
Cowpea
Soybean
Velvetbean
Sunn Hemp
Subterranean Clover
Sweet Clover
White Clover
Woollypod Vetch

Brassicas

Black Mustard
Brown Mustard
Spring Mustard
Fall Mustard
Kale
Forage Radish
Arugula
Rapeseed
Turnip
Winter Canola

Non-legume broadleaves

Buckwheat
Flax
Marigolds

How and when to seed cover crops

Just when should you plant cover crops? And how? For many, seeding is becoming the biggest post-harvest activity. And it’s a process that each farmer needs to work out for their specific management approach.

Some farmers turn to air-drills right behind the combine, then turn to aerial-applied seed when time runs short. Others turn to high-clearance applicators that can move through a standing corn crop to apply cover crop seed. The key is timing that planting to get solid emergence before first frost.

This section looks at aerial application and its costs, explores how different cover crops get started with fall seeding and provides some tips and insight on best practices for establishing them no matter what planting method has been used.

Establishing a cover crop requires some key practices that can help get the crop established, and in this section there’s even an answer to a key question: What if a cover crop doesn’t germinate?

Grazing and forage options

If you’ve got cattle on the farm, they can be a perfect pairing for a cover crop program, provided you have the right crop. Certain types can be grazed if established in time, and provide an extended grazing season while reducing your need for stored forages.

This section explores the use of winter cover crops for grazing and how best to deploy the practice in your operation. The use of winter cover for early spring grazing is popular in the Southwest, but is gaining popularity farther north as more growers turn to this technique.

Using the practice can help with cattle feed economics too buy saving feed costs, keeping cows cleaner during mud season and you spread manure nutrients with no added fuel or labor.

There’s also a discussion of fall-grazing covers and how best to use that practice.

How to terminate cover crops

This section of the cover crop guide deals with one of the more challenging issues for farmers on their first time – terminating them to make room for the spring crop. There are different ways to approach termination from the timing to the approach (chemical or mechanical), which can impact your farm.

There’s a discussion of how herbicide carryover impacts your plan, which can be challenged since cover crops aren’t usually listed on many herbicide labels.

And there are termination tips to maximize your approach to clearing covers for the new-season crops.

Calculating almond orchard crops

Cover crops aren’t just for corn, soybeans and cotton fields. Orchards are finding new ways to protect soil between the trees and boost soil health too. This section digs in on the practice offering insight for this key orchard crop, but also provides help for farmers with orchards of other types from applies to cherries.

A healthy cover crop in an orchard can offer improved soil health and structure, boost fertility and reduce erosion. While many almond orchards moved away from cover crops, many are returning to the practice, which can also help reduce the need for herbicides.

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.

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.”