CHAMBERSBURG, Pa. — Newly established forage stands require time and an opportunity to express their growth. Stretching from late summer to early fall we have an ideal window to walk and assess our newly seeded cool-season perennial forages. It is important to know what we are looking for when evaluating new stands and when to cut our losses.
Producers spend a lot of time making these decisions each year, mainly on the back end of a forage life cycle, when we consider removal or renovation of our more mature stands. Decision making can be more difficult when the stand is young and has never been harvested. How do we know when to pull the plug on struggling stands? Here are a few considerations:
- We can begin with assessing plant population. If the crop is a legume, like alfalfa, we can count stems and crowns. For an establishment year legume crop, the target will be 39 or more robust stems or greater than 20 crowns per square foot, in the fall of the year. If you are assessing grasses or mixed grass/legume stands, this is done usually by measuring overall composition. There is some variation in the literature, but generally stands should have at least 40-50% desirable species. Stands in poorer condition than above may be candidates for renovation.
- We can also look at field uniformity. It is ideal to have evenness of our planted species. Fields with large bare spots or patches with less than 20% of our planted forage favor renovation.
- Let’s also take a look at our weed populations, observe what weeds do we have and how many are there? Newly established legumes or legume mixes with high populations of perennial broadleaf weeds (like Canada thistle, hemp dogbane, and milkweed) can be challenging to manage economically.
- Consider limitations with re-establishment. We should be mindful of alfalfa autotoxicity when making replant decisions. For those with spring seedings, replanting is often possible in August or September with minimal concern. Fall seedings may require 6-12 months planted to another forage. Don’t forget about herbicide carryover! We can be limited in our renovation choices by the products used in preceding crops, consult your product label for information on rotation restrictions.
- Lastly, how flexible can we be? We should consider our goals whether that be restoration or renovation. Do we have the funds, equipment, and time to prepare a fall seeding of another forage or cover crop? Are we willing to rotate into annual forages? These are important questions to ask. Production years like this, where we have experienced moderate drought in portions of the county, complicate decision making. Forage yields have been impacted in many areas and it can be disheartening looking at a newly seeded stand experiencing the same stress. Some may choose to let the borderline stand overwinter to gain some needed moisture to be reevaluated in the spring; if you go this route develop a plan in case the stand does not recover.
- We should also spend some time determining if a seeding has done poorly in a response to low soil pH, fertility, or perhaps increased insect or disease pressures. Routine soil testing, sound field preparation, and timely pest management will give us the best chance at successfully establishing forages. Though not exhaustive, the list above can assist us with our stand assessments and decision-making.
For more information on forage management, please visit Penn State Extension’s website at https://extension.psu.edu/ or contact your local agronomy educator.
–Brittany Clark, Penn State Extension, Justin Brackenrich, Penn State Extension