Crop Comments: Winter forages link consecutive growing seasons

As crop growers enter late August, especially across the northern U.S., they become quite aware of night temperatures starting to drop. Such happening starts slowing the production of warm season crops (soybean, corn, sorghum, sudangrass, their hybrids and millets). As these warm season crops start fading, cool season crops can thrive. These don’t seem to keep close track of growing degree days the way that the warm season crops appear to. Stands of clear-seeded, cool season grasses (if fed nitrogen (N) and sulfur (S) and receiving adequate autumn rainfall) can give good yields in early October.

Note: Cool season crops will not dry down fast in autumn; thus wide-swath, same-day haylage, treated with the proper probiotic inoculant, will make high-quality forage. For those planting in mid-August, late summer-hardy forage oats offer the biggest yield potential. Planted at 3 bushels/acre of grain-type oats during that same timeframe, one can expect to harvest two to four tons of whole plant dry matter by the end of September in the Albany and similar areas.

Replicated research at the Valatie (NY) experimental farm, under Cornell’s oversight, showed no increase for higher seeding rates. Delayed planting will reduce yields dramatically. September’s normally cool nights conserve sugars, producing highly digestible forage fiber. With adequate N, plus S and manure, forage oats should easily achieve 18% crude protein.

Oats have increasingly suffered from rust infestations. Cornell agronomy researchers report that rust populations in NY have mutated to overcome certain oat rust resistance genes. (Oat rust is caused by a fungus in genus Puccinia). This mutation enables these fungus spores to infect older, previously resistant oat varieties. Scouts report exiting fields of susceptible oat varieties covered in rust spores, looking like large orange highway cones.

There are two rust-resistant oat varieties available: ‘Steuben’ and ‘Hayden’ (developed by Cornell plant breeder Mark Sorrells, Ph.D.). These varieties appear to have successfully countered rust issues. Lacking these resistant varieties, growers can survey to identify rust issues, then spray with properly timed fungicide to control rust. Growers are generally cautioned against planting late summer oats without fungicide. There have been cases where untreated oats were planted in late July (without fungicide) only to succumb entirely to the rust by the end of August. Sorrells also advised against indiscriminate use of neonics, since these pesticides can be toxic to honeybees.

Let’s now address winter forages, still often referred to as “cover crops.” Triticale is a hybrid of wheat (Triticum) and rye (Secale). Developed in 1888, this successful cross-bred yielded partially sterile hybrids. University of Nebraska-Lincoln (UNL) manages a winter triticale breeding program to complement winter wheat and winter barley efforts. Winter triticale’s main purpose is to provide western Nebraska locally adapted feed grains. Historically, not enough grain is produced for local livestock.

Of the fall-planted winter crops, triticale is less hardy than wheat and rye is the most hardy winter cereal. Winter triticale functions well as a forage or hay crop, producing more biomass per acre than either winter wheat or winter barley.

UNL agronomists seldom compare winter triticale to winter rye. Rye has a much greater tendency to produce volunteer plants the next year. In the Northeast, winter forages hit their optimum level of maturity (barely forming seed heads) from May 10 to 20. This is usually 10 days before perennial forages on neighboring fields yield the most digestible dry matter per acre. Autumn (and late summer) planted winter forages start waking up as the last snow finishes melting, while soil temperatures are still in the low 40s. Thus, triticale is harvestable, usually at 24 – 30 inches in height, as soil commonly hits the 50º F milestone (the point at which corn can be safely planted).

The winter forages – rye, triticale, wheat, barley or speltz – benefit well from manure applications during late autumn and winter. Most small grain experts believe that triticale can metabolize up to 70 lbs. of N from November through March. Semi-solid manure averages about 1% actual N. An acre of triticale can be expected to process and store the nutrients from about 7,000 lbs. of manure over the five-month period (70 lbs./1%).

The math gets shaky when it comes to rye: with rye taller than triticale, most agronomists recommend that growers limit N applications for rye to a total of 50 lbs./acre from November through March. Because of rye’s height (one to two feet more than triticale), much extra N commonly causes lodging.

Thus, presuming typical 1% actual N in semi-solid manure, let’s limit autumn/winter pounds/acre of that soil amendment to 5,000 lbs. Moving toward Labor Day, I recommend that growers plant the cheaper (compared to triticale) bin-run winter rye seed before planting the “grass” seed mixture next spring. This is because these “cold-footed” crop seeds can be planted into disked-up winter rye sod. It’s a good idea to allow seven – 10 days to “mellow out” rye’s allelopathic (natural weedkiller) properties. This practice will help the good guy seedlings avoid becoming victims of botanical friendly fire.

Seven years ago, I recommended that a Butternut Valley (Otsego County) dairyman plant a winter forage blend on a run-out alfalfa stand right after Labor Day. He planted 50 lbs./acre each of oats and winter rye, hoping to get a cutting before snow flew. He didn’t need the roughage, so he let the stand ride out winter. The oats froze to death, and the rye went dormant. I worried about the survivability of the rye. But the farmer and I were pleasantly surprised late the following March to see the rye waking up, successfully pushing through the thatched oats.

Here are eight plugs for winter forages as spelled out by Thomas Bjorkman, Ph.D., in a bulletin titled “Cornell Cover Crop Guide” (2010). Bjorkman wrote, “Cover crops can meet important management goals by:

a) Suppressing weeds
b) Protecting soil from rain or runoff
c) Reducing surface crusting
d) Adding active organic matter to soil
e) Breaking hardpan
f) Fixing nitrogen
g) Scavenging soil nitrogen
h) Suppressing soil diseases and pests

There are probably more, but these are a good start.

by Paris Reidhead