Using a nurse crop is a fairly common practice, but we do get questions on the how-to. Here are some frequently asked questions about nurse crops:
When should I use a nurse crop?
We recommend a nurse crop with any new seeding. This included pasture seedings as well as new alfalfa or alfalfa/grass stands. Regardless of weed pressure of the area the new seeding is going, nurse crops can be a useful tool.
Why should I use a nurse crop?
The most known goal of a nurse crop is to suppress weeds while the new plants establish. These seedlings, especially grass seedlings, are susceptible to being shaded out by too much competition. Many annual weeds are much quicker growing than the desired grasses or legumes, so they can quickly become deadly to new seedings. Even if weeds are not a concern for your new seeding area, nurse crops also provide erosion control. Root systems of the young plants are not going to be thick enough to protect the soil during a heavy rain or wind event. Nurse crops provide a quicker establishing root system to hold the soil in place. Another benefit of a nurse crop is proving your operation a source of forage from that ground on the new seeding year. That land would otherwise not provide anything in its first year, so using a nurse crop can be an economical decision as well.
What should I plant for a nurse crop and what rate?
A common nurse crop is cover crop or grain oats. These work well, but if you want to step it up a notch for forage quality and tonnage, you could use a forage oat like Everleaf 126. Forage oats can be used alone as a nurse crop at 40-50 lbs per acre or can be combined with forage peas and seeded at 50-60 lbs per acre. Adding peas can increase protein value in the forage. Some other options would be spring barley or spring triticale. Both of these would be earlier maturing that forage oats and would generally provide lower tonnage.
When should I harvest the nurse crop?
Harvesting the cereal nurse crop earlier, around boot stage, will result in higher quality forage. Waiting slightly longer will increase forage while providing slightly lower quality. Waiting longer to harvest for higher tonnage can also cause lodging and shading problems to your new seeding below. This leads us to the next point…
A question we ask: Do you want a lot of forage or a solid stand of your new seeding?
While it is useful to use nurse crops to provide forage, there is such a thing as too much of a good thing. If you are truly looking for high tonnage from your spring seeded forage, such as oats and peas, it may be better to plant them alone at a higher rate and not as a nurse crop. You could then harvest at the correct time to achieve maximum forage and quality and follow that with a late summer-early fall pasture or alfalfa seeding. This ensures your new seeding does not get shaded out or smothered out.
Let us know your other questions about nurse crops or new seedings!
When someone asks that, there are two response questions that should immediately come to mind: “What is your resource concern?” and “What is your window for seeding?” It is hard to say which is more important or which should come first (kind of like the chicken and the egg...)
Identifying your resource concern is something that should be happening at the same time as deciding your cover crop window. Here are some common goals of cover crops and how to achieve them:
Fixing Nitrogen – Utilizing cover crops that willfix nitrogen and then release it to the following crop is an amazing way to eventually lower input costs. A rule of thumb is that at flowering before setting seed is when legumes produce their peak amount of nitrogen. This means legumes have to have an adequate amount of time to produce enough growth to give you that nitrogen credit. This goal can generally be met for cover crops planted early spring, throughout the summer, and early fall with enough time before a frost. After fall harvest of corn or soybeans, nitrogen fixing options become limited. Keep in mind other nutrients that can be made available by cover crop such as phosphorus, potassium, sulfur, etc. when considering what to use in a blend. Nitrogen fixing cover crops are beneficial, but not as much when another nutrient is your limiting factor. Diversity in a blend to make as many nutrients available as possible is key.
Soil Structure Correcting – Compaction is an extremely common resource concern that producers want to address with cover crops. While brassicas like Pick-Axe radish are often the first to be desired, annuals such as annual ryegrass can be a great compliment to those deep taproots with their own fibrous, branching system. A mix of the two can do wonders for compacted soil by creating various channels throughout the soil for air, water and soil biology. To improve overall soil structure, almost any variation of a cover crop blend that has diverse species and root systems will do the job. That being said, the blend you choose is completely dependent on that previously mentioned seeding window you are able to use.
Forage – While it can be argued that a crop planted for a grazing or harvesting is simply a forage crop, many fit the role of a cover crop simultaneously. Need grazing in the spring before pastures are ready? A fall planted winter annual (like cereal rye) will provide that while also serving as a cover crop over the winter. You will have a living root in the ground all winter and the topsoil will be stabilized during spring rains. Need summer forage when pastures slow down? Use a soil building blend of summer annuals (like Summer Blend) to provide high quality forage and varying root systems to keep your underground livestock happy. For fall grazing, use a combination of annual grasses, brassicas, and legumes planted late summer to extend your grazing season into the fall while also providing cover on what may otherwise be bare ground.
Show that cover crop to your cows and your soil biology and they will both be interested!
This is the fifth and final way we respond to that statement in a series explaining the various windows for cover crops on most farms. Key word there is most, every farm is different and this can be adjusted in ways that work for you. Disclaimer: The dates of these windows will vary based on region!
This is generally the most common window of seeding that producers think of when it comes to cover crops. What is the downfall of this option? That red line that reads “Cut-off for Diversity” above. While, there is plenty of time to get something seeded after fall harvest, the options for diverse blends declines mid-September in most areas and not many fall harvested crops are off by then. That being said, this is still a great opportunity to seed covers!
Options before that diversity cut-off include cool season annual grasses, clovers, brassicas, peas, lentils and more! It all depends on your resource concern. Stick to the higher forage options if you want to graze. Use more legumes if you are trying to fix nitrogen for the next crop. Incorporate brassicas into the mix if you are trying to work on compaction and soil structure. Taking advantage of the opportunity before mid-September to add as much diversity as possible is very important. This is also an opportunity to get your winter annual small grainestablished to set yourself up for your quantum leap year!
Mid-September we stop recommending most clovers and brassicas as they will generally not get enough growth to provide enough benefit. So, what can you plant after that red line cut-off? Winter cereal grains are the main options, with triticale and wheat being cut-off in mid-October. That leaves cereal rye which, as many know, can be seeded basically up until the ground freezes. Cereal rye is stubborn and will continue putting roots down as long as temperatures are above or around 34 degrees. We have heard many stories of cereal rye being seeded at Christmas and still coming up in the spring as the first cover crop to green up (great for catching all the sunlight possible).
Many of the seeding options mentioned above have a dual purpose of cover crop and forage if you need it. As a cover crop, they hold soil in place and keep a living root in the ground as long as possible to feed your soil biology. The earlier-planted diverse blends can be stockpiled and rotationally grazed. This helps extend your grazing season in the fall. Even the later planted options can be grazed in the fall, but be careful with this as to not knock them out before winter. Those winter annuals can also be grazed in the spring to provide early forage and ground with a cover for calving.
The options for this window vary based on what your goal of the species seeded this time of year are, adjust to what is best for your operation and the year to come!
Brassica – what a strange word. It is the common term used to describe the wide variety of plants that are members of the Brassicaceae family. When referring to the cover crop and forage member of this category they can be generalized as flowering broadleaf plants with some form of taproot. There is a lot going on throughout these various types of brassicas. From radishes to rapeseed to kale, let’s see what they are all about.
Above Ground Action
The above sample was taken in September and analyzes the top growth on a radish that was sown in late summer. Things like the moisture content, nitrogen, and trace mineral results show us that this will break down quickly when it dies and release all that good stuff to our soil to feed the soil biology. The information like crude protein, NDF, and TDN tell us that it is going to be highly palatable and digestible to cattle providing a lot of energy in their diet.
The analysis of the same radish’s tuber is an excellent example of how brassica roots provide more than physical benefits to the soil. They also pull up and store nutrients such as calcium, phosphorus, potassium and sulfur. As the below ground portion of brassicas decay and break down, they will smell bad, but soil biology doesn’t mind. Your underground livestock are happy to receive the decaying material and will ensure these nutrients are available for any crops following the brassicas.
The physical benefits of brassicas, like the radish, are what is most commonly known about the family. Once radishes began being used as a cover crop to break up compaction, the news spread like wildfire. And it is true: the taproots and tubers on many brassicas will create physical channels through the soil to reduce compaction and create pathways for air, water, and soil life. However, it is not only radishes that will achieve this! Turnips, rapes, and radishes all have varying sizes and depth of taproots that can work to condition your soil. Some of our favorites to recommend are Pick-Axe radish, Barkant tankard turnip, and Barsica rape. Based on a full look at your resource concern and planting time, some or all three of these can be recommended to achieve correction of physical soil ailments.
Many of the above-mentioned brassicas have been bred for specific uses and are improved varieties in the Brassicaceae family. Common varieties of brassicas do exist that can serve as an economical way for you to add diversity of root systems or foliage to your blends. Things like Dwarf Essex rape and Purple Top turnips can fit this role, but keep in mind, these may not be as productive above or below ground as the improved varieties.
Overall, brassicas are a great way to add diversity to a cover crop mix to improve soils physically and through nutrient uptake and release. Many of these improved varieties can also take your grazing to the next level and extend your season. Now that you know all about brassicas, consider where they could benefit your operation!
This is the fourth come back that we have to that statement in our series explaining the various windows for cover crops on most farms. Key word there is most, every farm is different and this can be adjusted in ways that work for you. Disclaimer: The dates of these windows will vary based on region!
We often say that adding a small grain into your rotation can be the quantum leap for your soils. Not from the small grain alone, but from the ample time after harvest for seeding a diverse cover crop. This July to August time frame leaves options wide open for what to plant after your small grain. Towards the beginning of this window we would recommend warm season options such as sorghum-sudangrass, sudangrass, millet, cowpeas, berseem clover, and brassicas. Getting further into August, you could then switch to more of the cool season option like oats, barley, peas, faba beans, clovers, and brassicas. These lists are just the beginning of your options!
The benefits of this cover crop are endless. First, that bare ground will be safe from erosion and high summer temperatures with a cover seeded right away. For livestock operations, any manure that you may haul on this ground will be taken up and stored in your “catch crop" keeping it safe from run-off. Diving deeper into the benefits, blends that have such a large window of growth before a freeze will do wonders for your soil. Diversity in a blend means diversity in types of mineral uptake, types of soil biology attracted, and diverse levels of C:N Ratios when that cover crop is terminated. All of these working together to build and improve your soil. The varying root structures will feed different types of soil livestock.
Did someone mention livestock? What if we could use this cover crop to build our soil and feed our above ground livestock into the fall and winter? Summer annuals work very well for this providing an option for rotational grazing. BMR varieties of sorghum-sudangrass, suddangrass, and millet will provide extremely digestible, high quality forage. The later planted cool season options can stand up to a few frosts allowing you to extend your grazing season further into late fall and even winter. With rising hay prices, that grazing payoff itself can cover the cost of your seed!
This window could mean adjusting your rotation, but your soil may need the quantum leap that this cover crop provides!
Do you use a grass blend in your alfalfa stands? If not, here are some reasons to add grass to your alfalfa
A combination of grasses meant for dry hay mixed in with alfalfa will dry down faster when cut than pure alfalfa helping to protect your hay from rain damage.
Grass fills in gaps caused by standing water, alfalfa winterkill or alfalfa thinning over time creating less open space for weeds to establish.
Grass is less susceptible to wheel traffic damage and can help extend the longevity of a stand.
Adding a grass blend to your alfalfa can have higher yields than pure alfalfa.
Having grass in your stand that can last over time creates a thicker root system providing greater erosion control.
Grasses can also be added later on to thinning alfalfa stand to extend the lifespan of the stand
Forage Quality Benefits
Mixtures of grass and alfalfa meet forage requirements of beef cows better than pure alfalfa when looking at total digestible nutrients and crude protein.
The addition of grasses increases the content of quality, digestible fiber in the forage.
Grasses in the stand can reduce the risk of acidosis and bloat.
Convinced yet? On top of all of this, having diversity in species and root types is always beneficial to soil health and feeding your biology. Overall, the benefits of adding a grass with your alfalfa stands outweigh a pure alfalfa stand.
Cover crops can be a great way to manage manure, or lack thereof…. Let’s talk about how to put your legumes to work and when to make sure you have grasses and non-legume broadleaves with them.
Lazy Legumes -
Everyone wants their cover crop to work for them, especially when it comes to legumes fixing nitrogen. If you are not a producer that has manure to spread on fields after harvested crops, a blend heavy on legumes is a very good option to fix nitrogen and provide other nutrients for your soil. Where manure is applied, legumes don’t do as much work for you as they should. Legumes in those areas have plenty of soil nitrogen available, so they don’t need to give up any energy to connect with rhizobia and fix nitrogen. This creates those lazy legumes... So, what should be the focus in a mix where manure is applied? Catch Crops.
What is a Catch Crop? -
A catch crop will take up the available nitrogen and other nutrients that your manure contains and hold on to it for you. Grasses and non-legume broadleaves are the ticket here. Without the ability to fix their own nitrogen, these crops are very efficient in using their fibrous roots or tap roots to grab available nutrients. Those valuable nutrients cannot be lost to wind or water erosion or volatilization if they are safely tucked away in plant tissues. When your catch crop is terminated, those nutrients from your manure are put back into the soil where you need them.
None of this is to say you should not combine grasses and broadleaf plants with legumes. Please do! This is more about choosing what the goal of your cover crop is. No manure to spread? Focus heavier on the legumes, but still have the other species in there for forage quality and diversity. Have plenty of manure to spread? Still use legumes in the blend with your catch crop for the root diversity and added forage protein.
BONUS: The Pasture Side of Things –
This overall concept leaks over into the pasture world as well! Aside from the forage quality value that legumes and grasses have together, this symbiotic growth is another reason we recommend the pairing!
Focus on your goals, and choose the cover crop or “catch crop” that is right for you!
Lucky number three post in our series explaining the various windows for cover crops on most farms. Key word there is most, every farm is different and this can be adjusted in ways that work for you. Disclaimer: The dates of these windows will vary based on region!
Planting both grain and silage corn in an array of wide-row patterns has become a hot topic:
The goal of this type of cover crop seeding is very similar to Early Interseeding in the beginning few weeks. The difference is, with wider rows, we have more sunlight which gives us more time! There is not as much of a rush because the canopy in the wider rows does not close as much as 30-inch spacing. Just like with early interseeding, the blend you choose to seed depends greatly on the goals of your operation and the resource concern you are trying to address. Compaction? Have brassicas and annual ryegrass in your blend. Soil building and fixing nitrogen for the following crop? Use a heavy legume blend. Grazing in the fall? Use a combination of annual grasses, brassicas, and legumes!
At the beginning of this seeding window, many with wide row corn still use a drill to plant their selected species. With such a wide window of seeding opportunity, that corn is going to get tall towards the end. This is where a broadcasting seeding method becomes the most useful and some of the larger seeded cover crop species are no longer an option, unfortunately. Once drilling is not an option, many use some type of high clearance equipment with a seeder mounted and drop tubes attached link to youtube. This allows the cover crop seed to get as close to the ground as possible when it is seeded, avoiding too much getting caught in the whorl of the corn leaves. Timely rains when interseeding into wide rows is important for a quick establishment, especially when broadcasting.
Towards the end of this window, aerial application is also an option for both wide rows and regular corn rows. When flying cover crops onto corn, we aim for the corn to be at black layer so that when the seeds germinate there will be sunlight getting down through the drying leaves. If you are flying covers onto beans, we look for them to be starting to turn yellow for the same reason. The downfalls of aerial seeding are the need for a higher rate and, if there is not rain after the application to get those seeds sprouted, establishment can be difficult. There are many who still prefer this method to make sure cover crops get on all of their ground.
There is a lot of variability among options for this seeding window, but that just means there is a lot of room to adjust to what works on your operation!
Fescue is a word that many are afraid to say. “It’s too coarse.” “Cattle won’t eat it.” “It’s deadly to livestock!” Does this look deadly?
Those who say tall fescue is not palatable is almost always talking about what we call the “old fescues” like Kentucky 31 (cue dramatic music). Ever wonder what the 31 stands for? It is named so because it was discovered in 1931... Like many things in agriculture, grass breeding has come a long way in 88 years! Improved varieties of tall fescue exist and are vastly different from the old type varieties that many fear in their pastures. Improved varieties are soft-leaf fescues and are extremely palatable for grazing. These varieties are also a very long-lived, drought and heat tolerant part of a pasture. There are also hay-type fescues that have a more upright growth that work well for hay use; however, these are less palatable than the soft-leaf types for grazing uses.
Endophyte Toxicity (Alkaloid Toxicity)
Not all fescues have toxic endophytes! What is an endophyte? Endophytes are “organisms that exist in association with plant hosts, in foliage and/or roots” (Tymon and Inglis 1). In the case of tall fescues, the endophyte is a fungus that produces alkaloids. Two different types of alkaloids are produced: Loline (good guy) and Ergovaline (bad guy) Any tall fescues put in a pasture blend for the Midwest by PCS are endophyte free so they will not produce either alkaloid. Tall fescues with beneficial endophytes (such as Baroptima Plus E34) will only produce the Loline (good guy) that improves drought tolerance in Southern regions (Craig 1).
It is important to note that endophytes are only transferred to the seed of a plant that it already occurs in; therefore, there is no way for an endophyte free tall fescue to become endophyte infected or produce the previously mentioned alkaloids.
Don’t overlook this high energy cousin of Tall Fescue! Meadow fescue is a persistent, highly digestible grass. It grows well in cool, wet conditions and has similar growth habits to tall fescue. Meadow fescue will be beat in yield by tall fescue in most areas, but can be higher in digestibility. Meadow Fescue is also endophyte free like PCS tall fescues.
Craig, Paul. "The Fescue Family of Grasses." Penn State Extension, 19 Feb. 2013.
Tymon, Lydia, and Debra Inglis. "What is an Endophyte?" Biodegradable Mulch, Apr. 2016.
This is the second post of a series explaining the various windows for cover crops on most farms. Key word there is most, every farm is different and this can be adjusted in ways that work for you. Disclaimer: The dates of these windows will vary based on region!
Timing and moisture. Those are the two critical factors that we have seen affect early interseeding into standing corn (we have yet to see early interseeding be successfully applied in soybean crops). As you can see above, this is the narrowest window that this series is going to cover. Regardless of the seeding method you are using (we will get to that), getting the cover crop seeded between V3 and V6, or even earlier, is where we have seen the most success. The sooner the species you are seeding can get in there and begin building their carbohydrate reserves in their roots, the more they will thrive during the “dormant” shaded period and have a stronger start up when they receive light again.
The other critical factor is more out of our control. Moisture is important to get the cover crop started, especially when it is broadcast. Establishment can be difficult when our timely rains do not occur during this window or on very sandy ground that does not hold moisture well. If you do have good soil moisture, drilling can be a more successful option. How does someone drill or broadcast into standing corn? Take a look at some farmer-innovation examples:
Drill units can be lifted or turned off, air seeders can be mounted on just about anything, or use something else that you have on your farm! What types of seed are these machines sowing? For broadcasting or drilling, we often recommend our Interseeder Plus as a starting point. These are the species we have seen handle shade the best and provide grazing in the fall after harvest. If you are getting the seed incorporated, your options can increase to some large seeded options such as cowpeas, sunn hemp, mung beans, and buckwheat to name a few. These will also provide the option to graze in the fall! The actual species you seed depend greatly on the resource concern you are trying to address.
Having diversity in between your corn rows not only protects the soil from erosion and increase water holding capacity, but will also give your soil biology more to feed on making it more active. A more active soil biology will make more nutrients available for your growing crop in season. Legumes in your blends will not pass much of the nitrogen that they fix to your corn in-season, but they will be storing it in their tissues to release to the following crop.
If you want to add these benefits to your corn acres and have some additional grazing in the fall, consider this seeding window as an option!