Evaluation and Considerations on Newly Established Forages

Walking over stands, you will likely see spotty grass, scattered alfalfa, yellowing due to insect feeding or nutrient deficiencies, or areas where seeds didn't grow or grew and died. This is not only a disappointment from the financial losses suffered, but also a disappointment because you have livestock to feed or customers that want to purchase that forage. What do you do now? When is it time to give up and call it failed? When do we spray or mow? What are the other options?

We make many of these decisions yearly, typically on the back end of a forage life cycle, when considerations are made to remove a crop or rejuvenate a pasture. However, decisions for a new forage stand are much more difficult when it is four inches tall and has never been harvested. This article will get into considerations needed for evaluating the stand, whether it should be rejuvenated or destroyed and re-established, and your options for those decisions.

Stand Evaluation: Re-establish or rejuvenate?

The first step is deciding if you will try to keep the forage and start saving it, rejuvenating,  or if you will call it a loss and move to other options; such as destroying the current crop and re-establishing a new crop. Making this determination isn't as cut and dry as other assessments and will take some observations, but also intuition and thoughts about your management strategies.

When determining if renovation or rejuvenation is the right step, we must start with a visual assessment of the stand. First, notice the weed and desirable plant composition. Make sure you can identify the orchardgrass, bromegrass, or whatever species you planted, but the annual grasses or other broadleaves may be present. Proper identification is very important to making management decisions.

Next, we must look at stand health and vigor. If the crop is legume, like alfalfa, this is determined by counting stems and crowns. The target for an establishment year crop will be 39 or more robust stems, or greater than 20 crowns per square foot, in the fall of the year. If you are accessing grasses, this is done by measuring composition percentages. Publications vary on assessment percentages, whether you should re-establish at 50% desirable grasses or if it happens at 40%. A major factor in making decisions on grass stands is uniformity. Rejuvenation is likely the best option if the stand has grass throughout and does not have lots of bare spots. If your field has an inconsistent stand, 80% desirable in one area and 20% desirable in another, renovation will likely be the best answer. Observing the entire stand is necessary, not just a few locations. For more information read Hay and Pasture by Illinois University.

Fall-seeded alfalfa with leafhopper damage and Black Spot. Crowns have died leaving bare spots in the stand. Credit J. Brackenrich

We still have a few questions to answer after we have looked at stand assessments and compositions. First, what are the weeds that you are dealing with? Second, what was planted?  Third, field preparation and in-season management. Last, and possibly most important, how flexible are you in making management changes?

What are the weeds?

Consider renovation options if you are seeing high percentages of things like milkweed, Canada thistle, and hemp dogbane in a legume or mixed legume/ grass stand. Getting perennial broadleaf plants out of a legume crop can be time-consuming, ineffective, and expensive. If a lot of weeds are annual grasses like foxtail, barnyard grass, and crabgrass, then these are more manageable, not easy, but manageable, and you should not make your decision on them alone. A thought to remember: it is generally easier to get grass weeds from broadleaf crops and broadleaf weeds from a grass crop than getting grass weeds from grass crops or broadleaf weeds from a broadleaf crop. Getting the same type of plant from the crop is usually difficult and takes time.

What is the crop?

Forage species will impact the decision to re-establish or rejuvenate over the next 12 months. As mentioned previously with weeds, the crop can determine weed management, but it can also determine the next crop we plant or how we will harvest. For example, if you consider removing an alfalfa field, the autotoxicity associated with alfalfa means that we can not reseed that in alfalfa for 12 months. This field would have to be in something different, such as a grass or other legume, for at least 12 months, before returning to an alfalfa stand.

Something else to consider when looking at the present crop, which goes back to the 40/60 rule, is the amount of crop present and its condition. If you can go to an area of the field and find 80/20 desirable plants to weeds and in another part find 20/80, this is less favorable for rejuvenation than a field that is 40/60 desirable to weeds or 50/50 throughout.  If the plants are small and unexpressive, it is likely because something they need isn't present, like nutrients or water, which can be remedied. If plants are not there, it is difficult to fix that and fill in areas where crop doesn't exist. Large holes and low stand counts will favor renovations.

What was field preparation or in-season herbicide treatment?

Few management decisions can affect the next crop when planting forages, typically because we are not planning on a replant, but they do exist. An example of one of these, that is an herbicide application, is if Prowl H2O were applied during the summer to reduce annual grasses, like foxtail, then sorghum could not be planted until the next year, while alfalfa could be planted six months after the application. Other considerations for things like this would be tillage practices, weed management tactics, and nurse crops.

Lastly, how flexible can you be?

Many of the decisions that will need to be made will depend on your ability to make decisions and be flexible within your management. Understandably, you will need forage and feed for your livestock, but are you willing to consider coming out of a perennial forage and doing a year of annual forage to get the feed you need? Are you willing to allow the stand to over winter and see how it looks with some moisture? During the late summer, it is incredibly difficult to accurately determine establishment age forage, especially if it has been going through a drought. Having a plan for this season and next will increase your flexibility in case the crop does not recover, but also allow you more time to see if the investment will come out of its current slump.

Let's Rejuvenate

You decided to rejuvenate, and now the work starts. This season may be a loss, but we aim to get the field productive next year. Let's outline some steps to get the forage in the best position possible for the next growing season.

Weeds

If the top concern is weed management, start with weed control, but keep crop health in mind. During the late summer, the temperature is hot, and the ground is dry; the established cool-season grasses and legumes are growing slowly, or maybe not at all. While on the other hand, the weeds, and other undesirable species present have no problem expressing themselves. These weeds typically don't mind the heat and often have a more developed tap root for finding water.

To control weeds, we have a couple of options. Chemical and mechanical. Chemically speaking, if your forage stand is all grass or all legume, some options exist to help. If it is a mixed stand, things get more complicated, as was mentioned earlier. But before we can make an application, we have to ensure that the crop is physiologically ready and within the product's label to have a treatment, while being applied at the best time to kill the weed. For example, using Butyrac (2,4-DB) to control broad leaves in alfalfa or clover must be applied in spring to summer once the seedling alfalfa has 2 to 4 trifoliate leaves. However, it can't be applied above 90 degrees F, and it loses activity on weeds after they reach more than three inches in height and rosettes are two inches across not to mention the potential damage that can be caused to your crop that may already be stressed from heat and dry conditions.

These types of restrictions make chemical control difficult in the establishment year of forages and stress the need for starting new forage plantings on clean, weed-free fields. Also, consider more information on Spring Weed Control in Grass Hay and Pasture. 

The preferred way to manage weeds until you can get the forages established will be mechanically controlling them. Mechanical weed control will be useful to knock the tops off weeds before they get to seed and keep the spread and future germination of annual plants from continuing. This won't totally control perennial weeds, but it will provide some suppression, reduce spread through seeding, and reduce potential crop risk due to herbicide applications over stressed plants.  

Something to remember: once weeds are sprayed for suppression or eradication, unhealthy crops will not be growing enough to fill in the areas and keep new weeds from replacing them. Healthy crops can fill in these holes and provide more cultural suppression. This becomes the value of good agronomic practices associated with chemical and mechanical practices for forage IPM.

Fertility

If you haven't soil tested in the last three years, or you have and haven't amended your soils, now will be a good time to do that. If doing a soil test, watch this short video, Soil Sampling, for instructions on sampling and submitting the sample to the laboratory for analysis. After you have the results, look at Interpreting Your Soil Test Reports for more follow-up on how and what to apply. Recommendations are that lime and P and K fertilizers can be applied to forages in the fall so testing struggling ground in mid to late summer will make good timing for applications.

Be patient

As mentioned, hot dry weather will not be the friend of cool-season grasses and legumes. If weed management and fertility steps are followed, moisture will be the only lacking part of the puzzle. Remember that if you decide to re-establish, you are taking a larger risk by counting on rain with fresh seeding, so patience with a six-month plan should be easier.

Your choices are to allow the crop to continue to grow and see how it will express over the next six months, or make plans for next spring. If you are in a position where you are concerned with lacking forage by waiting on the crop over winter, plant an annual warm-season grass in late spring, or it could be to re-establish a new forage stand.

Let's Re-establish

Not ideal, but we must keep moving forward. Now that we have a decision, let's start making steps and understanding what got us here. Why did we make this decision? Weed management issues? Fertility concerns? Need for forage that isn't available?

Weeds

If weeds were the reason for this decision, there is likely room for improvement in your pre-plant herbicide activity or field preparation. Starting with a clean, burned-down field will be key to getting and keeping weeds out of new forages. Site selection and weed assessment in forages need to happen many months before planting to allow for treatment. When dealing with deep-rooted perennial weeds, consider using a small grain for a season to help with weed control. With a small grain, a burn down before grain planting, good winter and spring cover, and the opportunity for a later summer herbicide application after grain harvest, but before forage planting, will provide a much larger window for control. For more information read Relevant Herbicide Issues for Spring.

Other areas that can help future establishments are managing annual grasses in fields to keep seed banks low and knowing which fields will be reseeded a year ahead so weed control can begin earlier, rather than just at burndown. Check out Hay, Grassy Weeds, and Prowl for information on annual grass control.

Winter annuals and perennials can be an issue when planting forages. It is important to know the difference and understand their life cycles. Credit J. Brackenrich

If your renovation will start this fall, consider Fall Burndown of Weeds and Declining Forage Stands for more information on developing a good fall burndown.

Lack of crop

If a lack of crop presence is the reason for the decision for renovation, look back and consider how it was planted; this helps us not to make a similar mistake.

Was the soil fertility tested and amended? It is always important to ensure that the soil pH and P and K levels are optimum when establishing forages. When planting legumes, pH is crucial to establishment and should be maintained between 6.5 and 7.0. We have a little more wiggle room with grass crops, but since pH controls available soil nutrients, it should always be kept at about 6.0 for establishment. The P and K fertilization will promote root development and plant tillering, which we need for the interception of sunlight and water. Nitrogen is typically not recommended in the establishment year and should be done in small quantities if applied. Nitrogen will encourage top growth, which is good once it is established, but in the first year, the plant's job is to create its root system. For more information on fertility read Soil Fertility Management for Forage Crops: Establishment.

Ag lime is being applied to a hay field. Credit J. Brackenrich

If you are seeding with a nurse crop, that can result in decreased plant stands. Spring seedings use nurse crops to reduce soil erosion and weed competition, however, the nurse crop will compete for light, water, and nutrients. Water competition is the largest reason why nurse crops aren't recommended for fall seedings. If using a nurse crop, remember seeding rates are 0.5 to 1.0 bushels per acre of small grains like oats, triticale, or rye. The nurse crop job is not to be a cash crop for production, but rather, it is planted to keep the forage seeding productive. Seeding at high rates, over-fertilizing, and cutting past vegetative state will reduce forage productivity and health.

Seedbed preparation is another reason for the lack of establishment. No-till plantings are the preferred method of planting. Once it is tilled and disturbed, not only is more area opened for weeds, but it is very difficult to get the seed bed firm enough for good depth control. Typically, tilled soils must be cultipacked at least three times to get proper firmness. For more information on forage establishment, like nurse crops and seed bed prep, read Successful Forage Crop Establishment.

Re-establishment Options

As mentioned, care must be taken when selecting the next crop. This can be looked at from reasons including herbicide applications or the autotoxicity associated with alfalfa.

If you re-establish alfalfa, consideration must be made for soil-bound autotoxicities and allelopathic chemicals. If the crop was established in the previous fall, you must wait 12 months before returning to alfalfa. Consider going into a grass/clover mix if you need forage, thus removing the need to wait 12 months. If you are re-establishing into a spring-seeded alfalfa stand, the autotoxicity has not built up in the soil, and it is safe to make a late summer seeding.

Another option would be to plant a late summer cover crop, forage oats, peas, and millet, to provide forage matter for your livestock before winter, followed by an annual grass the following year, and a fall alfalfa seeding. Depending on geographical area, many of the cover crops can be planted as late as October. For more information on seeding read Recommended Dates for Fall Cover Crop Planting. 

For more information on selecting a cover crop look at What Cover Crop Should I Plant? and for more information on grazing or making stored forage from that crop, read Cover Crops for Livestock Grazing. If you are curious about warm-season annuals, you can read more at Harvesting and Feeding Warm-Season Annuals for Forage.