On this sunny afternoon, crocuses are taking over parts of our front yard. I even saw several honeybees hovering, bouncing between light lavender blossoms. Nearby, a quarter-century-old white birch is beginning to flow sap to its buds. These perennial plants and their six-legged friends are welcoming spring. Crocuses broke ground on an unusually warm day during which my efforts to sample soils were cut short by a serious afternoon thunderstorm. I marked the thunderstorm happening on March 19 in my calendar book, by drawing a small cloud, with three lightning bolts sticking out of it.
In terms of early signs of spring, every bit as important as crocus and birch bud behavior is the coming to life of winter forages. Winter forages – fall-planted wheat, rye, barley, triticale and speltz – are now providing the pleasant bright green framed by mostly drab tan perennial vegetation everywhere in the Northeast (crocuses being a pleasant exception to that statement). Ten years ago, my learned friend, Certified Crop Advisor Tom Kilcer, convinced me to stop referring to fall-planted small grains as cover crops and rather call them winter forages. In his mind, the new phrase portrays a more pro-active approach to professional cropsmanship than did the old concept. His March 2022 e-newsletter is titled “Nitrogen on Winter Forage.” His newsletters are at advancedagsys.com/newsletters.
He writes that most farmers growing winter triticale for forage are getting yields equal to or above what they expected, but are disappointed with the protein levels. With high soybean meal prices, the lack of forage protein hurts. Cornell-monitored field crop research tallied last year showed that a three-ton winter forage dry matter yield will remove 192 lbs. of nitrogen (N) at 20% crude protein. Insufficient N (and sulfur) will not only limit the protein of the crop but also drain the soil of available N, so when corn is planted following small grains, it does poorly for the first couple of weeks. A “treat-the-symptom-not-the-cause” cure is to put some starter N fertilizer in with the corn seed. The better answer is to put enough on the winter triticale, then any unused will be there to supply the corn. Insufficient N on a high yielding winter triticale forage can not only reduce your forage crude protein but can adversely affect the next corn crop. In spite of banded fertilizer, the fledgling corn will be yellow and slow growing until soil organic matter releases more N.
Kilcer writes that some growers spread manure and immediately plowed down in early September before planting winter forages. His research, as well as that of Penn State’s, indicates that this is not advisable in the Quaker State nor the rest of the Northeast. The savings on fertilizer does not offset the yield loss from the later planting. Growers are much further ahead to get the triticale in the ground around Labor Day, then inject the manure in November. His research has recorded storing up to 120 lbs. N/acre in the fall vegetative growth. His findings, plus those of Dr. Ketterings of Cornell, both agree “that in the fall, for every additional pound of dry matter you are growing, you store 22% crude protein or 70 lbs. of nitrogen per ton of dry matter. This reduces the amount you have to inject in November or December or purchase next spring, to meet all the nitrogen and sulfur needs of the crop.”
Kilcer stresses that winter forages are more than just tons of dry matter per acre: their nutrients are critical for economical dairy forage. In this study, they found at the zero spring N rate roughages tested 9% crude protein. Quoting Kilcer again, “Where we put 120 lbs. of nitrogen – plus sulfur – we got 19% crude protein. The early September manure did not carry through. In this research, we calculated that the payback in soybean meal you didn’t need to buy because you added spring fertilizer was $2.50 of soymeal not needed for every $1 spent on nitrogen.”
He said that despite all the pleasant field conditions of late last autumn, many growers still didn’t get a chance in December’s weather to inject manure into their winter forage crops; they still have a chance this spring to do so, as soon as the soil supports travel. Growers who planted on time and had six to 10 inches of growth usually observe that crop metabolizing about 50 lbs. N/acre the previous fall, especially if the field had manure the preceding spring, before corn was planted. For a three-ton dry matter winter forage crop, he suggests 9,000 – 10,000 gallons of manure injected, depending on what the manure tested. This, along with autumn N uptake, supplies enough for the total of 192 lbs. of N – higher yields will need more – to reach 20% crude protein, thus optimizing spring yields.
Kilcer advises against topdressing manure on winter forage, especially crop that is six inches or taller. The manure sticks to the foliage; rain will not wash it off, meaning that manure will end up in baleage or haylage. Adding insult to injury, 74% of the N spread on standing forage volatilizes, doing nothing for your crop. Save the manure for corn fields where you can immediately incorporate it just before planting. He says that if you don’t inject, he recommends using fertilizer N with an anti-volatilization agent so the crop gets all the N bought and paid for. He strongly stresses to remember sulfur (S): Apply it in an 8:1 or 10:1 N:S ratio to maximize protein and yield. This S requirement makes sense. There are two S-bearing amino acids that are critical for almost all protein synthesis – methionine and cysteine. The DNA molecule, bearing genetic programming, assumes the shape of a double helix, resembling a spiral staircase. Linking these helices together are S atoms.