Crop Comments: Corn chopping off to a slow start

Generally, most Northeast haymakers were satisfied with their 2026 first cuttings’ quality. At most locations, first-cut perennial forage tonnages were adequate to exceptional, except for much of Central New York: Utica’s TV weather reports showed June through August rainfall tallies ran about one-third to one-half of normal. This lack of precipitation extended northeast into the Adirondacks.

Despite overall hay supply adequacy in the region, few crop people offered hay for sale (at least in the Sept. 30 issue of this newspaper). Some folks, whom I advise, planted hot climate (drought-tolerating) summer annuals (sorghum, sudangrass, their hybrids and/or millets) and were glad they did.

Disappointed hay growers who also grew corn hope their silages will yield neutral detergent fiber with higher digestibility. Livestock nutritionists from the Ithaca-based Dairy One said that if the corn crop behaves more like fiber forage than a starch forage, the following scenario could offer a viable feeding strategy for some farms: Feed the more fibrous feeds to dry cows and heifers, leaving starchier feeds for lactating cows. These feeds cannot be accurately classified without laboratory analysis (one of Dairy One’s services).

At first glance this growing season, many corn stands show less lignification, with thinner and more flexible stalks (a quality plus). In areas where water shortages hurt perennial second-cutting regrowth, a plus flipside to this coin may well be improved whole plant digestibility for nearby corn stands. Unfortunately, improved yield tonnage may not accompany this improvement in feed quality.

Many ag journalists stress the topic of corn populations. Not everybody agrees on the subject, with many farmers (and most seed sales reps) strongly pushing more seeds per acre. A common corn population recommended by Cooperative Extension back in the 1970s (when I was a member of that organization) was 24,000 plants/acre. A seed drop of 27,000, with 90% germination in a 36-inch row, delivered such. With that row width, plants were about seven inches apart.

As field research increasingly documented the benefits of narrower rows intercepting more sunshine sooner, in-row plant spacing increased to 10 – 11 inches, still resulting in roughly 24,000 sprouted seedlings per acre. These days, narrow corn rows have become the norm: 20 inches or less. And often, in-row separation looks like six inches, with each seedling being assigned about 0.73 square feet (43,560 sq. ft. per acre / 60,000 plants/acre).

My friend and Certified Crop Advisor Tom Kilcer recommends the solar-hogging 20-inch corn rows, but aims for a population at 24,000/acre. According to the Farmer Grows calculator (farmergrows.com/corn-plant-spacing-calculator), corn planted at 27,500 seeds/acre with 95% germination will produce 26,136 seedlings/acre; in a 30-inch row that will result in eight inches between in-row plants. With the same setting on each drop tube but with a 36-inch row, with eight-inch spacing (between seedlings), plants per acre would only be 21,780. But with 20-inch rows, in order to achieve a seedling population of 26,136/acre, the space between seedlings would be 12 inches (30”/20” x 8”).

As I write on Sept. 29, most corn stands have some time to go for optimum silage maturity. But some areas, particularly those with shorter corn season varieties, are being aggressively chopped. Dairy One scientists noted that some farmers feel compelled to start chopping early, but those eager beavers may lose some starch potential – thus some of the milk potential support – this season gives.

According to Kilcer, “I am seeing a separation of fields that are 30% whole plant dry matter (DM) and 30% starch, and fields that are 31% DM and 34% – 35% starch. The latter will dry down at (a rate of) 0.75% – 1% per day. The fields where the DM and starch are even will be the more traditional 0.5% per day. This is why whole plant status is so important to monitor … even more so than milk line and visual appearance.”

While corn silage harvest season is still young, let me make the following five points:

1. The record high growing degree days (GGDs) in a few Northeast locations has put their stamp on some corn, promising impressive yields; other areas have had ear fill issues from untimely dry spells. But overall, pluses outweigh minuses.
2. Fields appearing green from the road often have ears with lower moisture content, which accelerates dry-down.
3. Custom harvesters opening up kernel processors (if fields appear green) may result in half-nicked kernels.
4. Operators without processors may start too late for the kernels.
5. In many situations, there’s enough time (10 days to two weeks from this paper’s date) for corn that is 30% whole plant DM, particularly shorter season varieties, to be harvested and ensiled properly.

Let’s sum up GDD observations in our region, starting with the basic four items crops need to perform satisfactorily: sunshine, warmth (both air and soil), precipitation and soil health (and nutrition). The fourth item is the only one that growers really control.

Here’s my simple approach to measuring GDDs. The base line for this measure is 50º F. Thus, a day that averages 70º is said to have amassed 20 GDDs. According to my August electric bill, my hometown (Hartwick, NY) logged an average temperature of 68º. With 31 days, August accrued 558 GDDs. July had an average temperature of 71º, so it accrued 651 GDDs. The math shows that August experienced 14.3% fewer GDDs than July, which explains, somewhat, corn’s retarded maturity.

Pay attention to introducing this year’s corn crop to cattle diets, particularly if silage exceeds 70% moisture. Rule of thumb: For at least five days, limit DM intake of green-chopped whole plant forage to about 5 lbs. (Jerseys a little less, bigger cows a little more). If this green-chopped whole plant forage DM is 25%, then daily pounds fed should not exceed 20 (5/0.25). When introducing green-chopped corn to cows’ diets, if at all possible, just chop on the west side of the field: plants in the next (still-standing) row can enjoy the solar radiation that their carted-away comrades no longer absorb, enabling them to dry down just a little bit faster.

by Paris Reidhead