Crop Comments: Don’t call ‘em cover crops
My first contact with Tom Kilcer was toward the end of my 63-month Cooperative Extension career. I met him at an Extension Conference in the Catskills in autumn 1977. My last year as an agronomy county agent was 1977-78, which was also Kilcer’s first year in that calling. Our contact over the following years was hit-or-miss.
In 2012, I interviewed a prominent Midwest seed dealer who praised Kilcer’s crop research conducted in New York. I told that dealer that I knew Kilcer from way back, so he gave me his number. When I called Tom, he invited me to see his crop demonstrations at the Cornell Research Farm in Valatie, NY. As a Certified Crop Advisor, Kilcer oversaw field operations at Valatie.
For most of summer 2012, over 40 states in the continental U.S. officially declared drought. The Valatie Research Farm in Columbia County suffered its fair share. When I visited Valatie around July 20 that year, the research farm had received about one inch of rainfall in the preceding 45 days. Most of the corn hybrid plants had shriveled up to almost nothing. Sorghums, sudangrasses, their hybrids and millets appeared unfazed by rainfall absence.
Obviously, the corn hybrids had fallen victim to the drought, so Kilcer planned to harrow up this pathetic-looking corn and plant cold-tolerant small grains. When I asked him if these would be his cover crops, he verbally jumped on me, saying, “Don’t call them cover crops – they’re winter forages. They’re not just hanging onto soils. They’re next year’s earliest mechanically harvestable forages.” Some things you never forget – like Kilcer’s response to my question.
In Kilcer’s September 2024 online newsletter “Crop Soil News” (at advancedagsys.com), he wrote that more farms in more countries, including Canada and multiple states in Europe, now capitalize on growing high yielding, high-quality, winter triticale forage. He pointed out multiple benefits for adding this crop to regular rotations. The first is reduction or elimination of soil erosion. Even fields with shallow slopes can erode over winter. The ground freezes from the top down. During warm spells, the top inch changes from frozen mud to ooze, as frost thaws from the top down. Snow melt or a winter rain can remove nearly all of this layer, leaving thinner topsoil, subsoil and stones behind. Thin layers removed each winter result in little or no topsoil on slopes (and too much in the hedgerow or ditch at the bottom of the slope). Total yield on such fields suffers.
The second impact from lack of winter forage strikes directly at operators’ wallets, according to Kilcer. Fertilizer nutrients that they paid good money for are leached out, denitrifying or being converted into much less usable forms. Nitrogen (N) can be held in green tissue at the 22% crude protein level through nearly all stages of autumn growth. When managed this way, such plants can be shown to store up to 140 lbs. of N/acre.
If we achieve these top yields (hopefully 1 to 1.5 tons/acre of dry matter) going into winter, we are looking at 60 to 100 lbs. of N/acre stored in the northern (New York and New England) climate zone. Farther south, more N storage can be expected. Kilcer said there is ongoing research to determine how much N storage actually occurs.
Additionally, phosphorus, which can be complexed (tied up in unavailable compounds with other soil elements), is absorbed and held in the plant in an organic form (organic meaning carbon-based, not chemical-free). Potassium in some sandy soils can leach, but, once again, not if it is incorporated in the physical biomass of growing plants.
The third arrow in the winter forage quiver is more important over the long term: soil health and structure. By growing a living crop all year, root exudates support vital diverse microorganisms. This in turn naturally reduces disease and pathological organisms, allowing beneficials to build soil structure in, and under, winter forage sod.
Research has found that soil health and structure deteriorate greatly over winter under bare soil. Kilcer observed the effect of such soil destruction in the Green Bay, WI, during 2024. Fields with previous winter forage had corn that grew nearly normal. Fields lacking winter forages (prior to planting corn) had large areas of drowned or severely stunted corn with pockets of good corn all in the same row. Their yields were estimated to be half the yield of the winter forage-treated fields. Same soil, same horrible (extremely wet) weather, yet very different results from incorporating winter forage in the rotation.
Reading between the lines of Kilcer’s discussion, I can glean that the temporary stands formed by winter forages make soil and sod healthy enough to fend off weeds – bad ones like Palmer’s amaranth, a member of the pigweed family.
Something I stumbled into in the non-agricultural arena added a dimension to this concept. The following question appeared in my inbox not long ago: What does “amarantine” mean? There were four choices. I chose the word “undying.” I was correct. (The other choices were “fragile,” “perishable” and “delicate.”) Quoting this Words Trivia source: “Definition of amarantine: referring to something that is everlasting or unchanging; immortal or eternal. Origin: Derived from the Greek word ‘amarantos,’ meaning ‘unfading,’ which is related to the amaranth flower, symbolizing immortality.”
Crop growers in the Midwest (more so than the Northeast) are in continuous battle against glyphosate-tolerant Palmer’s amaranth. This problem is worse in areas heavy with corn and soybean and really light on winter forages. This weed’s scientific name is Amaranthus palmeri. Crop growers fighting A. palmeri could call it “undying,” but probably call it something else, using more colorful wording.
In 2025, most of the Northeast sustained a seven- to 10-day hot spell in July where daily temperature peaks exceeded 95º F. This heat stress hurt some pollinating corn very badly, but didn’t faze sorghum, sudangrass or millets. And it didn’t faze volunteer heat-loving A. palmeri, whose seeds blew into western Pennsylvania and New York.
by Paris Reidhead
