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Close up of alfalfa in field
GETTING ALFALFA BACK: If the alfalfa you counted on is winter-killed, try no-tilling oats or corn to get your rotation back on track.

Short on winter forage? Try these steps to get back on track

Nitrogen and sulfur are both critical for yield and quality.

By Thomas Kilcer

Each year there is a crop that Mother Nature takes delight in hammering. This year it is winter forage.

Corn did not come off until mid-October in most places, and the fields were a rutted mess that needed to be smoothed over. Winter came at a normal time with most areas getting significant snow by Thanksgiving.

Some stands I have seen have one plant per square foot. A few farms, though, have winter forage planted on time and doing very well.

Nitrogen and sulfur are critical for both yield and quality. To get both yield and protein from your forage, crops need sulfur. In my research, we have found that as nitrogen increases, crude protein peaks at about 15% to 16%. When we added sulfur to the spring top-dress or switched to fall preplant manure with its sulfur content, the forage crude protein increased to 20%. The minimum is to add 1 pound of sulfur to 10 pounds of nitrogen.

So, what is our yield potential and how much nitrogen will we need to meet both yield and quality goals? For the few who planted on time, at least 120 pounds of nitrogen per acre, plus sulfur, is the minimum to optimize yield and quality if there was no manure. If you were lucky to have manure spread before planting on time, the manure should maximize yield, and the same 120 pounds of nitrogen will still be needed to maximize crude protein.

For those who planted late and have 2- to 3-inch-tall plants with minimum tillering, an early application of 100 pounds of nitrogen, plus sulfur, may help the limited spring tillering and still meet the needs of 18% crude protein on a 2-ton-dry-matter-per-acre yield. Keep in mind that these are guesses based on 20 years of research conducted when the fall was not a mess like 2018.

If you think you have less than 2 tons of dry matter per acre, it may not be worth it to harvest — treat it like a cover crop. If you are very short of forage, then use the 2-ton-dry-matter-per-acre yield recommendation and get what you can. Any leftover nitrogen will feed the next corn crop.

Those of you who used a sod injection rolling coulter last fall will be all set for nitrogen and sulfur.

Do not apply nitrogen on snow-covered ground. It is a prescription for high financial losses and low return on the crop. Losses can be as high as 44%, with an average loss of 26.3%, when applied to cold or frozen surfaces, especially if they are high in water or have some snow on them.

Adding an anti-volatilization agent in spring, even in low temperatures, will inhibit the urease enzyme from splitting the urea into ammonia, which is then lost. The anti-volatilization compound increases the chance of full return on fertilizer money. With milk prices where they are, you need maximum return on your fertilizer dollar.

What to do with winter-killed alfalfa

Alfalfa went into the winter very stressed from excessive rainfall. “There is long-term evidence that stresses like excessive or insufficient moisture and nutrient deficiencies interact with diseases to induce more severe symptoms and more rapid plant death,” according to Gary Bergstrom, plant pathologist at Cornell.

Diseases normally held at bay by genetic resistance can run rampant. Magnifying this is many farmers’ tendency to buy cheaper seed with less disease resistance.

Fields that are at the recommended pH will yield better, especially in the presence of soilborne diseases. But with the low milk prices, lime applications have been neglected the past four years.

This fall, fields in my area had diseased, yellow alfalfa, except for over the tile lines. Adding insult to injury, several states had little or no snow cover when the real cold weather settled in.

Snow can be an excellent insulator. More farmers are finding that leaving the low-yield last cutting captures blowing snow and gives better spring yields. Without it, snow blows off and extreme conditions can kill alfalfa, grass, winter forages, weeds, etc.

We also had multiple events of frozen ground and complete snow melt, leaving lakes and ponds in the fields. This is perfect for snow mold, which can hammer both seedings and winter forage.

So, what are your options if the alfalfa you counted on is dead? The quickest way to re-establish them is to immediately no-till in oats and red clover. The oats will take advantage of the dying alfalfa’s nitrogen and produce high yields of high-quality forage by late June. This replaces the first-cutting alfalfa you lost.

Harvesting the oats at flag leaf — just before the head emerges — will give you good-quality forage but will also minimize any lodging from the variable nitrogen left by the winter-killed alfalfa. I suggest red clover because dead alfalfa produces a compound that keeps new alfalfa plants from getting started.

Dennis Cosgrove and Dan Undersander explain autotoxicity in “Seeding alfalfa fields back into alfalfa.” The red clover is not affected by the alfalfa compounds and can give you a 2- to 3-year forage crop to get your rotation back on track. Red clover can be dried for silage the same day it is mowed using modified wide-swath techniques. You can learn more about red clover’s benefits here

No-till corn is an option, too

Another option, and often the simplest, is to finish killing what is there and plant no-till corn to take advantage of both the nitrogen (you only need a starter) and the improved soil structure — rotated corn usually yields 15% to 20% higher than continuous corn.

This will give you a low-cost forage supply but will mess up both your planned rotation and forage-storage capacities. If you don’t discover the missing hay crop until you pull in to mow, then one-cut sorghum or sorghum-Sudan planted later may be better.

Another option is to plant a short-season no-till corn at the earliest possible time to have mature corn silage on Aug. 1. Then, immediately no-till an alfalfa seeding. My suggestion is a floury kernel-type corn as many short-season corn varieties have flint-type parentage, which means the kernels get hard. I have double-cropped corn and alfalfa seeding several times and was able to establish an alfalfa in early August.

Andy Brizzell, field manager at the Cannon farm in Johnsonville, N.Y., has been doing this for years. It is a normal part of his rotation, allowing him to harvest an early corn silage and establish a new alfalfa seeding the same year. Of course, anything that delays corn maturity — prolonged dry period, cool or cold summer, extended rainy conditions — will delay the corn harvest and subsequent chance of getting the maximum out of your alfalfa seeding. If it is too late for alfalfa, red clover can be established. If it’s early September, try winter triticale.

Kilcer is a certified crop adviser in Kinderhook, N.Y

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