Fall is an important time of the year to check the condition of your pasture, fertilize, mow, harrow, and get rid of winter annual/perennial weeds. A little work this fall can provide big returns next spring and summer.
Inventory Pasture
It is a good idea to take a detailed look at your pasture in early fall to assess condition such as the percent of ground cover by desired species, grass/legume mix, and weed problems.
Fertilizing
Fall is a good time to apply fertilizer. It is wise to have a soil test done to get the correct
amounts applied. If your pH is less than 5.5, consider using lime at the recommended rate to correct the pH. Clovers and some legumes may need a pH of 6.0 or higher. Early fall is the best time to apply phosphorus and potassium because this is when root regrowth and replacement is taking place. Fertilizing can also help grass species increase when being pressured by some clover species if mild, instead of using herbicides to decrease the percent of clover.
Grazing and Mowing
Intensely grazing and then mowing the longer forage to a minimum of 4 inches will knock the weeds down and keep longer grasses from lying over. This also removes habitat for some vertebrate pests. This will help expose winter annual/perennial weed rosettes so you can spray them with herbicide more effectively.
Weed Removal
Fall is a great time to spray biennial weeds when they are in rosette stage. Most biennials will be translocating sugars and starches to their roots to get ready for winter. This helps the herbicide reach the roots and give better results.
Broadleaf herbicides will damage or kill legumes such as alfalfa and clovers. Spot spraying weeds in legume/grass mixed pastures may be your best course of action. Sometimes a wick or applicator can effectively apply a concentrated herbicide to tall weeds in a legume/grass pasture.
Remove weeds along fence rows that may seed into your pasture by pulling and disposing or burning.
Remember to wait at least three days after mowing to spray herbicides. A clean, healthy, actively growing weed is the most susceptible to herbicides.
Harrow/Dragging
Harrowing or dragging breaks up manure clumps and flattens small mounds of dirt. More severe harrowing can increase oxygen and water penetration and open up the soil for overseeding. Breaking up manure piles can expose parasite eggs and larva, helping to decrease their numbers.
Overseeding/Reseeding
Most grass species will decrease over time leaving more undesirable species and spaces for weeds to grow. Until your pasture reaches the desired health, quality forage seed should be overseeded every year, usually in the fall. Fall usually provides moisture and less weed pressure. Overseeding works best after opening up the soil by harrowing if possible.
Overseeding will also be more effective if you can remove the animals for at least 6 weeks but you will have even better results if you wait a few months for seedlings to build a better root system.
If early fall moisture is low, consider overseeding using fall dormant timing. Prepare the soil early but wait until the soil temperature is below 45 degrees before seeding. The seeds will lay dormant and soak in moisture until the soil warms enough for the seeds to germinate in the spring.
If there are areas that have a relative low percentage of desired species then you may want to consider reseeding. If biennial and perennial weeds are bad, spraying with a weed/grass killer first may be beneficial. Prepare the seedbed and reseed the area with quality, certified seed. Fencing off these areas is beneficial so that the roots can become established and the ground can become firm so that the animals do not pull the young seedlings up when they begin to graze in the spring.
Recovery Time
At least 6 weeks is needed for forages to store the necessary reserves before a hard freeze, so don’t graze or mow too late in the season or too short. The survival of your desired species may depend on it. If you have the ability to put animals on a sacrifice area it helps provide recovery time for the plants as well as giving your new seeds a chance to root deeper. Damage during wet weather and compaction also decreases the success of pasture forages.
Time spent on fall pasture management is time well spent for a more productive spring and summer pasture.
Debbie M. Williams
WSU Extension Walla Walla County Bulletin # 142