Will leaving corn in the field to dry until late spring be a viable option?

Bruce MacKellar<$authorEmail> and Roger Betz<betz@msu.edu>, Michigan State University Extension - November 22, 2019

The key factor to consider in deciding whether to leave corn in the field until spring is to assess the risk of yield losses by leaving corn in the field.

June-planted corn between one-fourth and one-half milk line on Sept. 20, 2019, from a southwest Michigan corn field. Warm conditions helped late planted corn to catch up, but has left moisture levels extremely high going into harvest this fall. Photo by Bruce MacKellar, MSU Extension.

What is the potential for corn to dry in the field over the winter months? In all honesty, not particularly good on a per day basis during the December through February timeframe. However, there are a lot of days during this period, and even small amounts of drying per day can lead to much lower moisture levels by early spring. With corn moisture levels remaining above 30% in many June planted corn fields, the cost of drying corn this fall is going to be very high. When considering the options, producers need to balance the risk of yield losses from leaving corn in the field with the cost of drying the corn.

Joe Lauer, University of Wisconsin Corn Extension specialist, conducted a study looking at corn yield losses over winter during 2000 and 2001. The results are in Table 1.

Table 1. Corn yield losses over winter, 2000 and 2001.
Year	November	December	January	February	March	April
2000	No loss	45%	58%	59%	65%	38%
2001	5%	5%	9%	19%	7%	10%
Mean	3%	22%	32%	37%	32%	24%
Moisture	37%	28%	27%	23%	20%	15%

Yields shown in Table 1 reflect the percent harvest loss by month. In 2000, there was heavy snowfall, which impacted how much corn the combine was able to get into the machine. In 2001, there was much less snow, and hence, less overall losses.

A partial budget analysis investigating the net revenue per acre impact of leaving 150 wet (30% moisture) bushel per acre corn in the field overwinter to dry to 18% moisture compared to taking this corn to an elevator to dry. The results showed that corn at 30% moisture left to field dry, with a 30% expected yield loss, would still have a $20 per acre advantage over drying the crop this fall. This assumes that there will not be substantial loss of grain quality over the period that the corn remains in the field.

The table below provides the breakeven for various corn moisture levels in the fall and expected yield loss from field drying.

Table 2. Estimated net revenue per acre impact of leaving corn in the field to dry over winter at various yield loss and harvest moisture levels compared to fall delivery to elevator.
Moisture	Loss %
	5%	10%	15%	20%	25%	30%	35.0%	40%
	Bushel
	7.5	15	22.5	30	37.5	45	52.5	60
35	$232	$204	$176	$148	$120	$92	$64	$37
34	$217	$189	$161	$134	$106	$78	$50	$22
33	$203	$175	$147	$119	$91	$63	$35	$8
32	$188	$160	$133	$105	$77	$49	$21	-$7
31	$174	$146	$118	$90	$62	$34	$7	-$21
30	$159	$131	$104	$76	$48	$20	-$8	-$36
29	$145	$117	$89	$61	$33	$5	-$22	-$50
28	$130	$103	$75	$47	$19	-$9	-$37	-$65
27	$116	$88	$60	$32	$4	-$24	-$51	-$79
26	$101	$74	$46	$18	-$10	-$38	-$66	-$94
25	$87	$59	$31	$3	-$25	-$52	-$80	-$108
24	$72	$45	$17	-$11	-$39	-$67	-$95	-$123
23	$58	$30	$2	-$26	-$54	-$81	-$109	-$137
22	$44	$16	-$12	-$40	-$68	-$96	-$124	-$152
21	$29	$1	-$27	-$55	-$82	-$110	-$138	-$166
20	$15	-$13	-$41	-$69	-$97	-$125	-$153	-$181
19	$0	-$28	-$51	-$84	-$111	-$139	-$167	-$195

The values in Table 2 were calculated using 150 bushels per acre wet bushel yield which had a test weight of 50. Drying charge was calculated at 4.0 cents per bushel per point of moisture above 15%. A shrink calculation of 1.4% per percent of moisture above 15% was used to calculate the number of marketable bushels. Drying charges, trucking charge for hauling the water in wet corn and a deduction of 5.0 cents per bushel for test weight were calculated on a wet bushel basis.

Factors that can contribute to overwinter yield losses

As you might expect, there are several factors that can contribute to overwinter yield losses and the risks for loss can be substantial.

Lodging. Corn has the potential to lodge, which can substantially reduce harvestable yield. This is particularly true where stalks have been weakened by tar spot or other leaf diseases or stalk rots. Leaf diseases causing loss of green leaf tissue during the growing season can cause the plants to scavenge carbohydrates from the stalk, reducing stalk strength and increasing the potential for lodging.

Ear size and weight can also play a role in this, with heavy ears creating more potential for lodging. In addition, activity of insects such as corn borer and, to a lesser extent, western bean cutworm can impact stalk and ear shank strength, causing more lodging and corn ear drop.

Lodged corn — Corn affected by tar spot that lodged following high winds. Stalk strength should be determined before deciding to leave corn in the field to dry through the winter. Photo by Bruce MacKellar, MSU Extension.

Winter weather. No precipitation events are created equal. Wet snow tends to be more problematic than dry snow. Ice storms can also add weight that can increase lodged corn. High wind conditions during any of these events, including wind driven thunderstorm rainfall during the winter, can cause significant lodging.

Wildlife damage. Deer can be a significant factor in making the decision of leaving corn in the field to dry. Overwintering deer can choose to yard up in standing corn as an alternative to woodlands and swamps, causing unacceptable levels of yield loss. The extent of damage that will occur is directly correlated with the numbers of deer in your area. If you expect to have fields you will not harvest until late winter or early spring, contact your local Department of Natural Resources biologist to request extra doe antlerless deer tags this fall and round up hunters to proactively reduce the deer herd in your area.

Producers will need to weigh their anticipated risk for yield loss and make harvest decisions based on their corn moisture, risk of yield loss and drying cost.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).