Prevent Plant? Maintain Soil Health with These Useful Tips

When fields are open during late spring/summer, whether part of a planned system or created by unfortunate weather, it’s critical to keep soils covered, taking advantage of the longer seeding window and maintaining soil health benefits.

Keep these items in mind if prevent plant is a possibility within your operation:

1. DO SOMETHING. Leaving ground fallow greatly increases risk of erosion and improves the likelihood of leaching nitrates, sulfates and other nutrients that could be used by the following year’s crop. Bare ground also encourages risk of “Fallow Syndrome” the following year. Fallow Syndrome occurs when there’s no plant growth in an area for an extended period. Populations of “good fungi”, called active mycorrhizae, are reduced because they need actively growing roots to survive. These fungi depend on host plants to complete their life cycle. Adding a grass (ryegrass, oats, etc.) or legume such as peas or hairy vetch are extremely beneficial and will better support the good fungi in the soil.

2. DETERMINE YOUR GOALS. There are many “cover crop” options available to use. The crop rotation goals of the producer should help steer the decision. Normally, crop harvest can often limit the time we have available to plant a cover crop, but because our planting window is now early, just about everything can be considered. Again, this should depend on what the producer wants to accomplish with the cover crop planting.

3. UNDERSTAND THE GUIDELINES. If taking the full prevented plant option, haying or grazing is not allowed until after Nov. 1 (or other dates in the Midwest, depending on state or region). Check with your state or county FSA office for further info on grazing restrictions with this program.

4. THINK ABOUT HERBICIDE RESTRICTIONS. Consider herbicides already applied on acres not yet planted. In many cases, cover crops and other non-traditional crops will not be listed on the herbicide label. Many universities are doing more work on this topic to determine what options farmers have in the case of “prevent plant” or other cropping systems that offer quick seeding windows. If a cover crop is being planted for erosion control and won’t be harvested, the grower then assumes the risk if that cover crop doesn’t appear on the herbicide label. However, if that cover crop will be harvested as forage, either mechanically or by livestock, then rotational restrictions on the label must be followed. For more information on herbicide rotational restrictions, refer to FAQ #5 in the Soil First® Management Guide.

5. USE MIXES. Cover crop mixes allow for diversity and opportunity to spread out risk. Mixes also allow for reduced weather risks, help break pest cycles and prevent erosion that some monoculture species are vulnerable to. Added benefits include nitrogen fixing and improved soil health as well.


As always, double check your plans with your crop insurance agent to ensure compliance. For late planting dates and other information for your state, see below:
Iowa, Minnesota, Wisconsin:
Illinois, Indiana, Michigan, Ohio:
Kansas, Missouri, Nebraska, Colorado:
Montana, North Dakota, South Dakota, Wyoming:

For more info on insurance programs, including early and final planting dates by county and state, visit:

Spring Cover Crop Reminders

Cover crops typically mean additional residue in spring, which brings about additional management considerations, detailed below.

Cover crops and green manure can harbor insects, diseases and nematodes harmful to subsequent cash crops. Armyworms, cutworms and other pests present additional management considerations after grass cover crops (i.e., annual ryegrass), cereal grains and even legumes (crimson clover, hairy vetch) due in large part to soil surface residue.

Armyworms can lay eggs in grassy cover crop fields, and young caterpillars attack corn mid-spring through early summer. Armyworms also move into corn from surrounding wheat fields, causing damage primarily along field edges.

There are labeled armyworm insecticides available and many growers include this with burndown application, however, armyworm populations may not yet be sufficient to warrant the cost.

Instead, scout fields often after corn planting. While it may be difficult to find armyworms, inspecting their damage is easier. Refer to local threshold recommendations to determine if and when to apply insecticide (foliar applications have proven successful).

Slugs & Voles
Slugs and voles may increase with introduction of cover crops and no-till. Many growing practices that leave surface residue can lead to enhanced habitat for these pests. For growers practicing no-till or reduced tillage, have solutions that don’t result in added deep tillage (minimal tillage may be necessary in some situations).

Below are steps to help cover croppers minimize occurrence of slugs and voles, especially in fields where it’s been a problem previously:

  • Plant cash crop early. Faster establishment = less feeding from slugs as crop will be too large to feed.
  • Keep roadsides & ditches/waterways mowed. This will decrease vole protection, especially when breeding is heavy and numbers are growing.
  • Control or terminate cover crops 3-4 weeks before planting to decrease residue.
  • Ensure seed slot is closed and firm. This will reduce direct feeding on the seed (may require deeper seed placement than usual).

Early cover crop termination and residue management at planting can reduce risk of pest damage. Insecticide may be required if planting into standing cover or within 3-4 weeks of termination. However, remember that surface residue creates a more diverse soil ecosystem versus conventional tillage systems and often attracts beneficial insects too. For nematodes and diseases, select products to meet your goals, plan early and manage accordingly.

How much and when nitrogen (N) will be available after grass cover crops is a common question with no easy answer. The rate and extent of N release from decomposing grass cover crops depend on many factors, including plant stage at termination, carbon to nitrogen (C:N) ratio and weather.

Plants in the vegetative stage have higher N concentration than those in the reproductive stage and decompose faster. The C:N ratio determines timing of N release from these residues. High C:N cover crop residues (>25:1) will first use and deplete N from soil or recent fertilizer N additions. Only after some time will N begin to release back to the soil.

For grass cover crops, terminate in the vegetative stage if the following cash crop is a grass, such as corn. If the cover crop reaches the reproductive phase before termination, more N will be used after termination and an additional starter N fertilizer application will be needed. This is crucial for the health of newly seeded cash crops.

Not all N scavenged by the cover crop will be available the next season, so fertilizer N rate should not be reduced by the amount of N kept from leaching (some scavenged N goes toward building soil organic matter). Grass cover crops, while in the vegetative stage, have C:N ratios around 10:1-15:1 and release N rapidly after termination. Roughly 50% of N in the above-ground biomass will be available over a window of 1-2 months, depending on weather.

Pesticides used now on cash crops can still impact cover crop establishment later – especially if cover crops are seeded prior to harvest. When interseeding cover crops it’s important to follow pesticide guidelines; those herbicides can affect cover crop germination, and established cover crops within the cash crop will alter the chemical options one can use. The industry continues to use information from several universities, listed below. We strongly encourage keeping these close:

University of Wisconsin:
Purdue University:
Penn State University:
Iowa State University:
University of Nebraska:
If using seeding equipment from your NRCS or SWCD office, consider reserving soon. It’s evident that machinery rental programs are working in many areas. However, most offices will tell you that the earlier they’re made aware of equipment needs, the easier it is for everyone coordinating these efforts come late summer.

Cover Crop Termination Considerations

Besides mode of action, there are a few factors to consider when selecting the correct burndown herbicide – like resistance and potential carryover.  Below are some factors with key burndown herbicides to keep in mind as the timing window for applications this spring is right around the corner.

  • Weather is probably the biggest consideration. Almost all herbicides work best when plants are actively growing (especially herbicides that are translocated). Cool and cloudy conditions often delay herbicide activity, and dry weather can increase carryover potential.
  • Glyphosate (Group 9) is a common burndown option. Glyphosate kills plants by barring the synthesis of amino acids (which can take up to a couple weeks to completely kill the plant). This chemistry needs to get to the growing point of the plant to be active. Thus, anything that prevents glyphosate from translocating within the plant will reduce its effectiveness:
    • Cold and cloudy weather
    • Premixes with glyphosate that kill plants quickly (like paraquat, for example)
  • Paraquat (Group 22) is another possibility. Paraquat terminates plants by triggering free radicals in the plant to build up and break up plant membranes. This happens quickly, usually within a couple days. Because paraquat is a contact killer, good coverage is needed to get control. Broadleaf control is more assured than with grasses, where a second application may be needed due to regrowth. Paraquat has zero soil activity, so carryover concerns aren’t a problem.
  • Glufosinate (Group 10) kills plants by disrupting ammonia recycling – which causes photosynthesis and other processes in the growing plant to stop. Like glyphosate, control of plants using glufosinate is greatly affected by weather – plants need to be actively growing to achieve adequate results. Good coverage is needed as this is a contact herbicide as well.
  • Group 4 herbicides (Auxenics) have a place in cover crop burndown applications. 2,4-D, dicamba, and clopyralid all fall into this category of herbicides that work primarily on legumes and other broadleaves. Auxenic herbicides kill plants by disrupting metabolic processes within the plant, usually taking at least a week for plants to die. Resistance to Auxenics in waterhemp and other weeds have occurred – and we know that several mustard species aren’t easily controlled with these products. We typically don’t see any carryover issues with Auxenics, although 2,4-D can cause some problems, depending on organic matter and soil pH.
  • Group 5 herbicides (Triazine family, metribuzin, others) work for burndown applications by stopping the photosynthesis process in the plant. These herbicides translocate differently than glyphosate, which means post applications are not as effective. Dry weather can reduce their effectiveness too. Several weeds have selected resistance to Triazine herbicides (like pigweeds, lambsquarters, velvetleaf, etc.). Because of their residual activity, consideration for the following cash crop (and cover crop) is important.
  • PPO Inhibitors (Group 14) like Sharpen and Reflex stop biosynthesis of chlorophyll and other pigments in the plant. PPOs typically work better on broadleaves than grasses, and affected plants usually die within a week. Resistance to PPOs has been witnessed across the country (waterhemp and palmer amaranth), and carryover concerns are valid with PPOs, especially on fall cover crops.
  • ACCase Inhibitors (Group 1) herbicides are used on grasses in post applications, and typically take about 2 weeks for plants to completely die. Examples of these herbicides are sethoxydim, clethodim and quizalofop. Like other herbicide families, ACCase inhibitors work best on actively growing plants. In dry conditions, expect these herbicides to have a reduced effect. Using Group 1’s alongside 2,4-D and other Auxenic herbicides have caused reduced efficacy. Some resistance has been seen in annual ryegrass to ACCase products so caution must be taken.
  • Many other options exist to control cover crops in the spring. Use caution and plan ahead for your best chance at success.

This chart is derived from the University of Wisconsin and Penn State University, with a few additional options our group has added based on experience in the field. If questions, contact us at 800.356.7333 or We have additional resources to help you make the best decisions this spring.

References: Shaner, University of Colorado; Hartzler, Iowa State University; Johnson, Purdue University;  Davis, University of Wisconsin; Curran, Penn State University.

The Importance of Clean, Weed-Free Seed

The Importance of Clean, Weed-Free Seed
We’ve been following reports lately related to noxious, problematic weeds like Palmer Amthe-dirt-9132aranth showing up in cover crops. Be sure to use clean, quality seed for cover crop plantings and keep these things in mind:

  • Use tested, noxious weed-free seed. A tag can tell you a lot. Look for certified noxious and problematic weed-free seed to optimize success and lower risk. Request seed test results to be sure.
  • Growing location matters. Make sure your seed is grown in areas with less humidity.
  • Use a supplier of seed, not grain. Professional seed suppliers procure seed from agronomically sound producers trusted to bring quality, weed- and disease-free seed into the market.

To meet the demand for quality assured, ultra clean seed, we offer Guardian™ Fall Rye. This brand is carefully selected and screened to ensure the cleanest and purest cereal rye for cover cropping, higher than industry standards.

10 Steps for Successful Cover Cropping

While cover crops won’t be seeded for several months, the cover crop key decision season is upon us.  Make sure you keep these steps in mind to ensure success:

  1. Have a Goal. Ask: “What do I want to accomplish by planting a cover crop and what benefits do I want to work toward?”
  2. Select the Right Cover Crops to reach your goals. There are many species on the market and each has a distinct set of characteristics to achieve different outcomes. Wrong choices lead to more problems.
  3. Have a Plan. Think about changes that may be needed to your current farming system to allow for correct establishment (and management):
    • Modifying crop rotation (perhaps adding another crop to your rotation creates a wider window in fall)
    • Altering previous crop’s harvest slightly for more timing flexibility
    • Adjusting herbicide program for timely cover crop seeding
    • Additional pass in fall and/or spring for planting and spring termination
  4. Select a Field or Areas of Your Farm that will benefit most from a cover crop
  5. Think Small Acres starting out. Consider new management concepts needed when first trying cover crops.
  6. Get Seed Ordered Soon. It may take longer than you think for less-traditional seed to arrive. Good, clean seed is the most demanded too (seed, not grain. Seed is professionally grown and maintained for good quality and germination).
  7. Allocate Labor and Equipment. Depending on your seeding plan, you may need extra help for prompt seeding after cash crop harvest. If the plan includes custom seeding, communicate plans early to ensure timely application.
  8. Consider Leaving a Check Strip for Comparison. How better to determine progress than by seeing uncovered ground side-by-side?
  9. Balance Goals and Spring Management Wisely. Even the perfect cover crop not managed or terminated correctly in spring can lead to setbacks for your subsequent cash crop.
  10. Make a Commitment. Some goals are easily noticed and well defined, but improving soil health is a journey, not a destination. It takes time to regenerate soil and demands producers consider long term expectations, no matter the initial goal or objective.

LINK™ Inoculant – Year One Lessons

Last year we introduced LINK™ Cover Crop Inoculant, a peat-based product designed to inoculate all legumes in one convenient package. We knew it’d be a hit for several reasons. What we learned this fall wasn’t surprising, but we want to share with you our findings:

  • After several presentations on the importance of inoculants, it surprised us how many questions arose on how long pre-inoculants survive on seed prior to planting. Remember, in many cases (aside from red clover and alfalfa), rhizobium that nodulate cover crop legumes are fragile and susceptible to desiccation.Depending on the strain, they won’t survive on seed beyond 24 hours. In contrast, rhizobium that nodulate alfalfa can survive on seed 2+ years. Beware of pre-inoculated cover crop seed. In most cases, there won’t be any surviving rhizobia.
  • Anytime you work with dry peat products you may run across a challenge or two at planting, largely due to moisture in planting equipment (humidity, dew, etc.). We didn’t uncover any issues with this, largely because LINK™ has a low use rate. It’s important to state again the correct procedure for mixing the product with seed:Mixing LINK™ and the seed thoroughly is important and even layering the seed and inoculant can improve this more. We also saw that slurry mixing worked especially well, but planting needs to commence as soon as the “coated” seed is dry.
Other Points to Keep in Mind:

  • Each legume requires a certain strain to nodulate properly. For example, the strain that nodulates red clover will not nodulate crimson clover, and peas and vetches require their own specific strains. Likewise, any leftover soybean or alfalfa inoculant will not work with cover crops.
  • LINK™ is designed to apply to the entire seed mix for ease of use and convenience. The advantage of applying inoculant to the entire mix is that the non-legume seed components “carry” inoculant into the soil, where the legume seeds are nearby. This provides more complete nodulation of the legume and enhanced nitrogen fixation than if the inoculant was applied only to the legume seed. Remember, inoculants are for the soil, not the seed!
  • LINK™ is included with Soil First™ cover crop legume mix orders of 500 pounds or more and can also be purchased as a standalone product
  • LINK™ can be used effectively on over 50 legumes making it a convenient option for forage plantings too
Other Frequently Asked Questions: 

  • How long will LINK™ stay viable after it’s been applied to the seed? 24 hours
  • Is LINK™ a GMO product? No. There are no ingredients of LINK™ that would render it a GMO.
  • Can I apply LINK™ at the same rate on straight legumes too, and are there enough rhizobium to handle a mono-culture legume seeding? Yes. With LINK’s high rhizobia counts there are sufficient numbers of rhizobia present to nodulate each straight legume on the label.

For more information, please review the LINK Technical Sheet, or contact us to learn more.

About The Dirt

The Dirt is a periodic email series with timely cover crop tips from the agronomic experts at Soil First and La Crosse Seed. If you have a question you’d like us to answer, contact us here.

When Will Radish and Turnip Growth Stop


Now That It’s Cold, When Will Radish and Turnip Growth Stop?

Differences exist in brassica species. Some varieties have been bred for increased tolerances to grazing and colder temperatures, to name a few:

  • 2-5 days of high teens/low 20’s will typically kill radish
  • Depending on your region, turnips can usually withstand cooler temperatures a little longer and actually become more desirable to cattle after light frosts. Expect turnips to terminate with several days in the low teens.

In some parts of the Midwest, however, especially in the southern transition zone or areas under heavy snow cover, turnips can survive much of the winter. Since controlling turnips in the spring is relatively easy, this usually causes no major concerns. Turnips may be slighted in their ability to sequester nutrients to help subsequent cash crops due to prolonged growth in the winter and their positive delay in releasing nutrients (compared to radish).

the-dirt-12-5-2Even small growth of radish will yield better-than-expected results.

Because the taproots of radish remediate compaction more so than the tuber, brassicas like radish that are winter-killed earlier than preferred may still generate a positive outcome (even though the more noticeable tuber looks too small to do any good).

This image shows a Soil FirstSelect Radish that looks relatively small above the soil surface, but boasts a taproot over 30″ deep.





It’s December – How’s Your Cover Crop Doing?While we’re out in the field we see what cover crops are doing and how they’re progressing. But we’d love to hear from you! There’s still plenty to understand and we appreciate comments from the field.
Send us photos of cover crops plus any comments on what you’ve noticed or learned so far. We’ll share photos and feedback with you in an upcoming The Dirt. Please send to or tag us on Twitter orFacebook.


Proper Timing for Aerial Applications



Proper Timing for Aerial Applications
Moisture or irrigation is critical when surface seeding cover crops to make up for the lack of seed-to-soil contact. When time could be a hurdle, aerial and “over-the-top” seeding offers a worthy alternative.

When aerial seeding, consider the ideal planting window for the cover crop being planted. For example, radishes typically need at least 4-6 weeks or longer of growth prior to winter termination. That planting period should be taken into account to coincide with the proper maturity stage of the crop in the field.


Image courtesy of MRCC Vegetation Impact Program

The Ideal Time to Aerial Seed into Cash Crops, Assuming Seeding Intervals Match

  • Corn: formation of black layer, or when at least 50% of sunlight reaches soil surface
  • Soybeans: between leaf senescence and 5% leaf drop, but that depends to some degree on row width and soybean architecture. Delaying applications into soybeans decreases seed-to-soil contact and increases risk of poor moisture retention needed for maximizing germination.
  • Sunflowers: back of the seed head turns yellow
  • Cotton: just before defoliation

When crop stage and seeding calendars do not align, always weigh on the side of earlier application, especially when a moisture event is forecasted or irrigation can be planned. Use the crop stage as a guide, but understand that in many cases, aerial seeding may be needed earlier to ensure enough time for proper establishment. It’s better to have the cover crop seed in the field to begin the germination process vs. planting later, where seed may have to compete with excess cash crop residue.

Remember, achieving the Growing Degree Days (GDD)’s needed for most winter-killed cover crops is between 600 and 1100. Achieving those heat units will take longer in different regions of the country. In any given year (using corn as an example), 50% light penetration to the soil surface may not be realized until a few weeks prior to first frost. In those cases, earlier applications will be crucial for success.

For other crops, concentrate on sunlight infiltration to the soil surface. Sunlight and moisture are the limiting factors for bare surface applications. Also, any kind of residue on the soil surface will further promote germination versus bare, flat soils.

The Importance of Clean, Weed-Free Seed
We’ve been following reports lately related to noxious, problematic weeds like Palmer Amthe-dirt-9132aranth showing up in cover crops. Be sure to use clean, quality seed for cover crop plantings and keep these things in mind:

  • Use tested, noxious weed-free seed. A tag can tell you a lot. Look for certified noxious and problematic weed-free seed to optimize success and lower risk. Request seed test results to be sure.
  • Growing location matters. Make sure your seed is grown in areas with less humidity.
  • Use a supplier of seed, not grain. Professional seed suppliers procure seed from agronomically sound producers trusted to bring quality, weed- and disease-free seed into the market.

To meet the demand for quality assured, ultra clean seed, we offer Guardian™ Fall Rye. This brand is carefully selected and screened to ensure the cleanest and purest cereal rye for cover cropping, higher than industry standards.


Understanding The Pros & Cons To The Mustard Family of Cover Crops

Understanding The Pros & Cons To The Mustard Family of Cover Crops

Radishes are popular for good reason, but additional brassica species are also used for cover cropping. There are hundreds of hybrid brassicas coming to market that generally offer increased forage potential, quick regrowth and significant above-ground biomass production. Below is useful information to consider in your cover crop plan.

Advantages & Disadvantages of Common Mustard Cover Crop Species:

Radish Chart

Radishes: Understanding the Differences

There are many radish options for growers today. Due to its rising popularity, use of daikon type radishes has grown steadily. It’s no wonder radishes are widely used – they offer many benefits without the need for spring termination. With numerous varieties and brands of radish at your disposal, it’s crucial to distinguish the differences.

  • Selecting a Variety with Proven Performance is Important. Because daikon types have a long, slender tuber and even deeper taproot, choosing an option with minimal taproots is imperative to maximize growth and density of that taproot.
  • Understand How Quickly Radish Can Bolt and Produce Seed. There are varietal differences in how soon radishes bolt, but all varieties will bolt to some degree, depending on planting date and climate. Less bolting means a larger percent of plants are putting energy into producing a deep taproot vs. seed production.
  • Understand Differences Between Daikon Types and Oilseed Types. The industry has done a poor job of using proper radish terminology. It’s not uncommon for people in the industry to identify the same radish as an oilseed variety, a daikon variety or even a fodder or forage radish…very confusing.

Daikon Vs. Oilseed Radish
For a visual comparison between daikon and oilseed radish, click here. To summarize:

  • Daikon types were first grown for human consumption and are known for a slender tuber. Advances in breeding has led to some varieties displaying an extremely vigorous taproot, which does most of the work to break up compaction and capture excess nutrients.
  • Oilseed types were first grown for oil production and although above-ground growth can look similar to daikon, the tuber is typically shorter and taproots are more lateral in nature. This doesn’t mean oilseed types can’t be used for compaction alleviation, only that oilseed types are more commonly used for nematode suppression and bio-fumigation traits.

Both types offer distinct advantages, and it’s essential to know that different characteristics will help deliver different benefits. For help deciding what’s best for your operation, contact us here.

Fall Rye Seed Selection: Factors to Keep In Mind

Fall rye seed 7

Fall Rye Seed Selection: Factors to Keep In Mind Fall rye is a popular cover crop in many areas. If fall rye is in your cover crop plans, here are some factors to consider when looking for seed to ensure an efficient cover crop operation and the greatest chance for success:

  • Seed quality impacts seed costs. Pay attention to purity and germination – less pure live seed can cost more than anticipated. Cheap seed may be exactly that.
  • Go with the pros. It’s important to buy seed from a professional seed supplier, known to procure seed from agronomically sound producers of seed, not grain. As an ASTA member, we encourage use of professional suppliers who bring quality, weed and disease-free seed into the market.
  • Seed laws vary from state to state. It’s important to understand the laws in your state and the source of the cover crop seed or small grain you’re buying.
  • A seed’s growing location can impact quality. Many seed fields grown in the Midwest and Corn Belt need additional management to produce the same quality seed as areas with less humidity, where most professionally-grown seed is sourced.

    Uncover the True Cost of Your Fall Rye

Higher Quality = Less Cost The economics show, along with less risk and added peace of mind, that a high quality cereal grain seed makes sense. If you’re comparing cost, we encourage you to uncover the true cost of your fall rye grain.

Quality Assured Fall Rye Demand is Increasing We’ve had many growers state that a trusted, clean rye grain is something they value. To meet that demand, we offer Guardian™ Fall Rye. This brand is carefully selected and screened to ensure the cleanest and purest cereal rye for cover cropping, higher than industry standards.

No matter what brand you choose, make sure to keep these factors in mind before making the investment.