MSU Extension Field Crops

I was sitting next to a cash crop farmer at an auction recently and I asked him, “Is the corn going to make a grain crop this year?” His reply was, “You tell me when we are going to get a killing frost and I’ll tell you if we’ll harvest grain.” Fair enough.

There is a risk this year that some fields of corn that won’t make a good dry grain crop. The Michigan State University Extension website has a record of Growing Degree Days (GDD) or the amount of heat for crops like corn from multiple weather stations around the state. Some areas of the state, particularly in the north, are behind in heat units compared to averages over time. Producers can use online data from local weather stations to forecast harvest dates.

What options does a grower have for harvest when he or she is not in the business of feeding the corn to livestock? These are times of opportunity for cash crop growers to partner with livestock feeders, creating a win-win for both farmers. The corn crop can be harvested in various forms that are salable  to those who feed cattle.

It all depends on the maturity the corn reaches by the time it is killed by frost. Corn that is nearer to completion of starch deposit in the kernels (black layer) may be harvested as high moisture corn. Ideally, kernel moisture should be in the range of 28-32% for harvest as high moisture shelled corn, because the goal will be to ferment the grain for preservation.

For farmers who feed either dairy or beef cattle, this is a product that is can be stored either in bunker silos or in a bag. It is dense and therefore does not demand as much physical space as would storing it as corn silage. Because of its nutrient density, it can be economically transported farther.

The value of the crop can be calculated by adjusting for moisture compared to the local price for dry shelled corn. If the crop has not reached black layer, then there should be an adjustment for decreased quality.

Depending on the buyer, the corn could be harvested as high moisture shelled corn, ear corn or snaplage. In each case the price will be based on the current price of dry corn and adjusted based on percentage of corn grain and moisture.

But what about corn that is not near black layer when it is killed? There are still options, but they are narrowed. Immature corn can be harvested for whole plant silage. This requires greater storage area but can be a rescue of a crop for a cash crop producer. It also presents a challenge in valuing the product because it is farther in quality from dry grain, the basis of the price estimation.

Here is what we know about the feed value of corn as it matures. Normally, we recommend harvesting corn for silage, based on moisture at ½ milk line, or prior to black layer formation. As corn approaches this indicator it adds starch and fiber decreases as a percentage of dry matter. Digestibility increases as it approaches ½ milk line because a higher proportion of the plant is grain. Crude protein decreases as the plant matures. Very immature corn should be fed to animals with lower nutrient requirements, while that which is closer to mature corn silage may be fed to lactating dairy cows.

The first consideration is to harvest corn at the right dry matter (32 – 38% DM) for ensiling. When frosted, the leaves will quickly turn brown and the plant may appear dry, but the stalk holds the majority of the moisture. Harvest some to check DM. The rule of thumb for plant dry down rate is half a point of moisture/day when it doesn’t rain. Therefore, if it is at 72% moisture when checked and you want it down to 65% moisture for harvest (7 percentage point difference) it will take 2 weeks (14 days) to get there. However, that dry down rate is under ideal conditions. Dry down in October is different than dry down in September due to day length and temperatures.

Whether planning to buy or sell standing corn for chopping, yield per acre can be difficult to estimate. The best practice is to run trucks across a scale and record the weights and number of trucks or wagons. If scales are far from the fields, it may help to run several trucks of corn to the scales and then use the average weight from those times the number of loads delivered.

If the corn crop is so immature such that won’t likely yield grain, a gross estimate can be made of tonnage by figuring the average height of the plants (minus tassel). Each foot equals approximately 1 ton of feed per acre.

Weight is a function of moisture content. Determining moisture is important for pricing. If price is determined based on 35% DM (65% moisture) and the material is 68% moisture, then price needs to be adjusted.

For more information on harvesting corn silage see these Michigan State University Extension articles by Martin Mangual: Corn silage refresher part 3: The process of preservation to maintain feed quality, Corn silage refresher - Part 2: Analyzing and adjusting during harvest, and Corn silage refresher – Part 1: How to set your cutting date.

Pricing

When pricing corn silage normally, it is often estimated by multiplying a factor times the current corn price per bushel. The factor is usually 8-10, based on the premise that corn silage contains corn grain, approximately 7.5 bushels per ton of corn silage when corn is harvested at full maturity. There is variation in that amount even in full season corn based on area, season, hybrid and more. Using a factor above 7.5 gives value to the stover as well.

If, for example, we used 9 as the factor and corn grain locally was $3.50/bushel, then the value of corn silage (CS) would be $31.50/ton of CS at 35% DM. It is important to use a corn grain price that is local because this is the alternative market for the corn.

For immature corn, we recommend adjusting the price down because of lower feed value; approximately 90% at early dent, 75-80% at soft dough stage. For example, CS harvested in the early dough stage – before dent – would be valued at $23.60 - $25.20 per ton (75-80% of normal CS price based on $3.50/bushel corn). These calculations are approximate and are used as a starting point for negotiations.

That pricing assumes the crop is harvested and ready for delivery. For purchase out of the field, one needs to adjust for harvest cost. For that, a reference for field operation costs is the Michigan State University Extension “2019 Custom Machine and Work Rate Estimates” bulletin. Chopping and hauling are estimated at $10 per ton of corn silage. These are imperfect tools based on surveys but can again be a starting point for negotiation. The harvest and hauling cost would be subtracted from the value of the corn silage for sale out of the field.

For more information on pricing CS, see the article by Michigan State University Extension Educator Jon LaPorte: Pricing standing corn silage.

Start conversations now

It would be wise for potential sellers to contract now with those who may be willing to buy immature corn, but each side needs to be aware of the risks. Any agreement on selling the standing crop needs to hold off on final determination of price until frost stops all growth. However, having a plan and an agreement for sale can provide peace of mind to a cash crop grower.

This type of purchase should be a win-win. The buyer is adding to his or her forage or grain supply with good feed. The seller is getting a rescue of a crop that he or she cannot otherwise sell, or only after high drying costs and then at a discount. If the buyer is harvesting it, then the seller is also saving costs. It is an agreement between a willing seller and a willing buyer that meets needs for both sides.

For more information, see the MSU Extension website on Delayed Planting Resources at https://www.canr.msu.edu/agriculture/delayed-planting-resources/ .