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Corn Silage Harvest on the Horizon

University of Minnesota Extension, Stearns County News
September 2, 2015         
Source:  Dan Martens, Extension Educator
University of Minnesota Extension
Stearns, Benton & Morrison Counties

Corn Silage Harvest on the Horizon
By Dan Martens, University of Minnesota Extension

FOLEY, Minn. (08/26/2015) — Corn in many fields is denting around the area. We move from stages like early dent when the whole plant moisture might be 73% or more; full dent around 71%; ½ milk line around 65% moisture; ¼ milk line around 63%; no milk line around 60% and the grain moisture might be around 32%...and a black layer starting to develop on the kernel tip. I use the milk line process where ¼ milk line means there is still milk about ¼ of the distance up from the bottom of the kernel.

I have one reference that says it might take 5 days to move from early dent to full dent, 5 days from full dent to half milk line - if weather conditions push things quickly. That seems really fast to me. So as the corn starts to dent, it’s time to watch the crop pretty closely for chopping corn silage.

Ultimately reaching the whole plant moisture that is correct for your storage and feeding practices is key. When we have good soil moisture, we can be fooled into thinking the corn is too green to chop. The grain makes up half of the total dry matter weight of plant. So when the grain gets down around a 35% moisture range and less, that weighs heavily on the whole plant moisture content.

With normal weather and crop conditions, once we get to where most kernels have started to dent, we might expect to lose one-half % whole plant moisture per day. So if we think we are around 71% whole plant moisture when most kernels have dented, we might drop 6% moisture and be at 65% moisture in around 12 days.

PRICING CORN SILAGE. With a better planting season and ample moisture generally, there might not be as many people shopping for corn for silage as last year, but there will be some.

Ohio State Extension posted an article recently about pricing corn silage. This can be found by doing a website search for “Ohio Extension Pricing Corn Silage August 2015”. You’re welcome to call us at the County Extension Office to get a copy. The article lists several links to related topics.

One article tells about a computer program (SESAME) that calculates a value for corn silage based on the value of 20 or 30 other feed materials. The article shows an example that resulted a “corn standing in the field price” of about $24 per ton. That’s in the range of a thumb-rule estimating that a ton of corn silage purchased out of the field might have a value of 6 to 8 times the price of a bushel of corn. This is based on expecting 6 to 8 bushels of corn per ton of corn silage. Some value for the fodder might be added to that. DON’T take $24 as the right number for your situation – do you own math. 

People who start negotiations with 6 to 8 times the price of corn should study a Wisconsin Extension Article about field trials looking at the variations and factors that play into bushels of corn per ton. With yields averaging from 25 to 200 bushels per acre and moisture ranging from 60 to 70% over several years, this ranged from 0 to 12 bushels per ton. Wisconsin Extension forage information can be found by searching for “Wisconsin Extension Forage FYI” or call the County Extension Office.

Moisture alone makes a huge difference. For corn at 125 bushels per acre, for example, if chopped at 60% moisture, these field trials averaged 14.6 tons of corn silage per acre and 8.5 bushels of corn per ton. If chopped at 70% moisture, they averaged 19.5 tons per acre BUT only 6.4 bushels per ton - because more of the weight is water. 

Wisconsin also has a worksheet for putting harvest and production costs and other information for estimating potential buyer and seller prices for corn silage. Testing corn silage for moisture and feed quality can be helpful in considering corn silage prices.

For the buyer, a key question is: What will I have invested in the feed when I put in in the feed bunk - when I add what I pay for the standing crop and my costs to chop, haul, and put it in storage? 

For the seller, a key question is: How does the standing crop stumpage value compare to my cost of production… and how does net income for the crop, if chopped - compare to the value of the grain I would harvest MINUS my cost for harvesting, drying, hauling, storage, or moisture deductions. What about the value of stalks left on the field with grain harvest?

At the end of the day, the buyer and seller need to figure out if there is a price that makes sense for their situation.


Daniel Martens
Extension Educator, Ag Production Systems
(320) 968-5077
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