Pastures producing more weeds than grass? Hayfields lost their legumes?
Fall is the time to start planning for spring renovations
Brown County Agricultural Agent Doug Sutter tells you how
In Wisconsin, fall is the time to walk through the woods to enjoy the crisp air and brilliant colors. It's also the time to walk through your pastures to determine whether they're in need of renovation. To help decide where - and how - to make improvements, Brown County Agricultural Agent Doug Sutter suggests making a map of your property, showing the slope of the land, soil types, plant species, and weed concentrations - and now is the time to do it. "Fall is perfect time to make a map of your property, " says Doug, "because its easy to determine things like density of desirable plants and weed concentrations in the fall, but it may not be so obvious in the spring."
Pastures and hay fields that have lost desirable plant species, are producing low yields of forage, or are excessively weedy are in need of renovation. Deciding whether to till and replant the field, to use a more conservative method like frost seeding or no-till drilling to increase desirable plant species, or to simply top-dress your fields with fertilizer will depend on weed content, soil condition, and terrain, as well as your budget.
WEEDS
If weeds have taken over 50% or more of your pastures or hay fields you may want to consider tilling and replanting in the spring. But if the problem isn't quite that serious, or if your budget simply doesn't allow a complete replanting, there are other ways to reduce weeds in your pastures - and fall is the time to start implementing them.
"The first step in addressing a weed problem is to determine whether your weeds are perennials or annuals," says Doug. "A good weed identification book can help, or you can take samples to your cooperative or UW extension agent for assistance."
Fall is also the best time to apply herbicide to the biennial thistles commonly found in Wisconsin pastures, because thistles are in the "rosette" stage in early fall and, in this stage, they are particularly susceptible to herbicide *
Frost Seeding: Frost seeding can be done in most areas of Wisconsin and is the easiest and least expensive way to increase the density of desirable plants in your pastures. "Frost seeding is done by spreading seed with a broadcast spreader on the field after the snow has melted but when temperatures still are dipping into the freezing range - usually in March or April in Wisconsin," explains Doug. "The repeated freezing and thawing that occurs at this time shrinks and expands the ground, helping to move the seed down into the soil. This eliminates the need to till, making the technique not only easy and inexpensive but desirable from the standpoint of soil conservation."
If you plan to frost seed you'll need to be sure the plants you select are suitable for seeding by this method. Alfalfa can be frost seeded, but certain grasses, like Timothy, aren't recommended for frost seeding. You'll also need to be sure your pasture has adequate drainage so the seeds aren't washed off the soil surface after they're applied. .
No-Till Drilling: No-till drilling is another method of renovating pastures without having to completely tear up the soil. In this method, a no-till drill is used to literally drill the seed into the existing sod. No-till drilling is suitable for planting both legumes and grasses, and when used to inter-seed legumes into a grass field, results in a more uniform mixing of the two species than frost seeding does. On the down side, it is more expensive than frost seeding and results in slightly more soil erosion
SOIL CONDITION
One very important factor to consider when in deciding how to best renovate your fields, is the condition of your soil. Fall is good time to test your soil, because soils that are deficient in certain nutrients or that are too acidic (low pH) may not support the growth of the plants you plan to seed in the spring. This means that you may need to fertilize, reconsider the type of plants you plan to seed, or till lime into the soil to correct the problem prior to seeding.
Alfalfa, in particular, will not grow in soil that lacks potassium or that is too acidic. If soil acidity is the problem, you'll need to either add lime to correct the soil's pH prior to seeding, plan to seed with a legume that's more tolerant of acidic soils like clover, or seed with grass only. ** Realize that , if you decide to add lime to increase the pH of your soil so that you can grow alfalfa, you will have to till your fields, because lime needs to be worked into the soil to a depth of 6 to 8 inches. "Lime won't work it's way down into the soil by itself," explains Doug. "If you just top-dress your fields with lime, the lower layers of your soil will remain acidic while the top layer will become very alkaline." Lime also reacts slowly and, ideally, should be incorporated into the soil 3 to 6 months before seeding legumes. This means that, if you plan to seed alfalfa next spring, it's best to work lime into the soil this fall. However, unless you're able to provide plant cover on the fields before winter, tilling in the fall can lead to excessive erosive losses. "You don't want to leave your soil exposed to the elements all winter," Doug warns.***
The University of Wisconsin Extension has published guidelines to help you collect appropriate soil samples for testing (Pamphlet A2100 "Sampling Soils for Testing"). As a general rule, you'll need to take one sample for every 5 acres of land and wherever soil type changes. Soil testing costs $12 - $15 per sample, so, for a 40-acre field, you should be testing at least 8 samples at a total cost of about $100 - but that $100 could save you a lot of money and frustration in the long run.
TERRAIN
Another factor to consider when deciding which method to use to renovate your pastures is terrain. " If your pasture is on a slope you don't want to till it, because if you tear the soil up, you'll subject it to a lot of erosion," Doug points out. "If you must till, do it late in the spring, so you get plant cover on the soil as soon as possible"
Finally, if you are planning to establish new pasture in an area that was used for a crop, like corn, this year, you'll need determine which herbicide was applied to the field, because many herbicides used on crops (e.g. atrazine) carry over and are toxic to pasture grasses and legumes.
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* The best time for applying herbicide to thistles is after thistle germination is stopped but while the plants are still actively growing and daytime high temperatures are in the 60s or 70s. This is usually early to mid-September in southern Wisconsin and perhaps a week or two earlier in the northern part of the state. Fall treatment of thistles will reduce competition from these plants in the spring and is recommended for pastures to be inter-seeded with legumes
** By using a complete fertilizer high in nitrogen on grasses and harvesting or grazing early (boot to early heading for harvesting) you can boost crude protein content of the grass to13-18 per cent. By contrast, unfertilized and late harvested or grazed grasses will generally be deficient in crude protein, containing less than the 12 per cent required for mature horses (UW Extension pamphlet A2460: "Forages for Horses").
***One option is to add lime and seed with grass only in the spring, and then inter-seed with alfalfa later in the growing season.
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