Field Notes talked pasture and forages

Phyllis Bongard, Educational content development and communications specialist, Craig Sheaffer, Extension forage specialist, and Troy Salzer, Extension educator

As the weather has alternated between drought and excessive rain, farmers that rely on producing high quality pasture and forage crops have been faced with many challenges. To address these issues and discuss management strategies, Dr. Craig Sheaffer, Extension forage specialist, and Troy Salzer, Extension educator, joined moderator Angie Peltier, Extension educator-crops, in the August 7 session of Strategic Farming: Field Notes.

Spring recap

Winter injury

After a winter with very little snow cover, Dr. Sheaffer expected to see a significant amount of alfalfa injury, particularly since it broke dormancy relatively early in the spring. Much to his surprise, there was very little winter injury to either alfalfa or forage grasses. Even without much snow cover, the mild winter temperatures just didn’t get cold enough to significantly damage the forage crops.

Rebound after severe drought

In many areas of northern Minnesota, there was little to no forage production during 2023 due to severe drought. Alfalfa, which is drought-tolerant, went into early dormancy and even weeds fared poorly. When the forages came out of dormancy this spring, they were in better condition than Salzer had expected. However, open areas provided an opportunity for weeds - particularly biennials like bull thistle and plumeless thistle - to take hold and impact pasture condition and quality.

1st crop challenges

Then in a complete 180-degree shift, excessive rainfall in many alfalfa growing regions made the 2024 1st crop harvest extremely challenging. The hay drying windows were very short and some hay was baled wet in less-than-ideal condition, which can result in heating, molding, dry matter loss, and even spontaneous combustion. When feeding these lower quality hays, livestock producers should watch for mold and dust, regardless of the livestock type it’s fed to.

One way to extend the drying window is to use a hay preservative, such as propionic acid. By acting on the microbes that cause heating and mold, the recommended moisture content thresholds for baled hay are expanded. The upper threshold will depend on bale type and size but using a preservative adds a degree of harvest flexibility and an opportunity to bale forage at moisture contents above 20%.

When drying windows are extremely short, utilizing a wet forage system also has advantages. Taking the forage as haylage or baleage cuts harvest time to one to two days instead of the three to four good drying days needed for baling hay. In addition, the high forage quality of haylage and baleage are maintained.

The harvest situation was better for second and later crops with wider forage drying windows. What if hay gets too dry? If high temperatures and windy conditions have dried hay too much, wait for dew to bring the moisture content back into an optimum range before baling.

Looking ahead to late summer and early fall

Mid-August through early September is the optimum time to seed new stands of alfalfa or complete pasture renovations. Early fall is also a great time to assess alfalfa stands. To assess a stand, take numerous square foot samples and count both the number of plants and the number of stems in each quadrant. Include variable parts of the field’s terrain, including low spots and high spots, and try to take a total of about 20 samples per field. A good stand of established alfalfa should have 3 to 5 healthy plants per square foot and 40 to 50 stems per square foot. New seedings should have 25 to 30 plants per square foot in the seeding year.

When you have a good alfalfa stand . . .

Be careful with fall harvest timing!

To ensure that alfalfa has enough time to store carbohydrates for the winter, avoid harvest during the period from 45 days before the first average killing frost (26F) to the actual killing frost. This cutoff date usually corresponds to sometime in early September, depending on location. Cutting alfalfa during this timeframe significantly increases the risk of winter injury. Alfalfa can be harvested after a killing frost (26 F) has occurred, but 6 inches stubble should be left to catch snow for a protective winter cover.

But if the stand is poor . . .

Interseeding

If there are gaps in an alfalfa/grass stand, interseeding in mid-August is an option. However, to be successful, the stand needs to be open or suppressed with herbicides or tillage. Otherwise, new seedlings will be unable to compete with the existing legumes and grasses. If an herbicide is used to suppress the stand, check the label for rotation restrictions. If seed is broadcast, some tillage will likely be needed to ensure good seed-to-soil contact for germination.

Fertilizing fields according to soil test results is also important. Fall is an excellent time to take soil samples and apply fertilizer.

For pasture renovation, an alternative to the mid-August timeframe is to suppress the grasses in the following spring and then seed with a no-till drill. This is also an opportunity to introduce a legume such as white clover or red clover into the pasture. Whether for pasture or hay, the keys to interseeding success include suppressing the stand and taking care of weeds and soil fertility needs.

What about frost seeding? In Sheaffer’s extensive experience, frost seeding is successful 30 to 50% of the time; however, it is an approach to introduce legumes into grass pastures. Use an inexpensive seed source and be sure to have soil exposed by fall grazing or tillage.

Terminating thin stands

If an alfalfa or mixed alfalfa stand is thin going into winter and it doesn’t look like it will be productive in the spring, think about terminating it and reseeding in another part of the farm. Since the stand is going to be terminated, the forage can be harvested anytime during the fall.

Extending the grazing season

Seeding cover crops as a supplemental pasture as soon as possible after soybean, small grain or silage harvest can extend the grazing season. Seeding options include mixes with annual grasses such as spring oats, winter rye, or winter triticale. Brassicas, like purple top turnips, are also often used in these mixtures as they put on a decent amount of biomass in the fall. Another option is to stockpile perennial forages for late fall grazing.

Stockpile a pasture

If enough pasture acreage and fencing is available, pulling animals out of a pasture in August and allowing dry matter to accumulate in place for two to three months – called stockpiling - will provide some additional grazing during the fall. Applying 50 lb N per acre in August will give grasses a boost in production. Meadow or tall fescue are best suited for stockpiling because they maintain forage quality after frost.

Looking to next year, consider having some pasture planted to sorghum-sudangrass or sudangrass to reduce risks of feed shortages caused by drought,. These warm-season, annual grasses will provide summer forage and some risk mitigation potential. For more information, see Fall tips for productive pastures.

Thanks to the Soybean Research and Promotion Council and the Corn Research and Promotion Council for their generous support of this program.