With the “grab-test” method, squeeze a handful of finely cut plant material as tightly as possible for 90 seconds. Release your grip and note the condition of the ball of plant material in your hand. If:
- Juice runs freely or shows between your fingers, the crop contains 75 to 85 percent moisture
- The ball holds its shape and your hand is moist, the material contains 70 to 75 percent moisture
- The ball expands slowly and no dampness appears on the hand, the material contains 60 to 70 percent moisture
- The ball springs out in your open hand, the crop contains less than 60 percent moisture
Then account for the influence of moisture when establishing price. Use 65 percent moisture silage at $45 per ton as an example. Each ton contains 700 pounds of dry matter (2,000 x 0.35). The value per hundredweight of dry matter is $6.43 ($45 divided by 7).
However, if the moisture content is 70 percent, then each ton contains only 600 pounds of dry matter. To have comparable value, this silage would have to be priced at $38.58 (6 x $6.43) per ton. On the other hand, if the moisture content were 60 percent, then a comparable price would be $51.44 per ton (2,000 x 0.40, which equals 800, and then 8 x $6.43). But remember, if the corn gets too dry, it will not ensile, so proper moisture is necessary to make silage.
To calculate on a dry-matter basis, the formula is ($ per ton x actual dry matter) divided by dry matter for silage. For example, to determine the price of corn silage at 20 percent moisture (80 percent dry matter) using the reference price of $45 per ton of 65 percent moisture (35 percent dry matter) silage, the calculation would be ($45 x 80) divided by 35, which equals $102.86 per ton at 80 percent dry matter.
As you can see, trying to find an equitable value for corn silage can be a little more work, so some prefer to start with the following pricing rules of thumb for corn silage that’s ready to feed, then adjust from there:
- 1 ton of silage is equal to approximately eight to 10 times the price of a bushel of corn.
- 1 ton of silage is equal to approximately six times the price of a bushel of corn plus harvest costs.
- Corn silage is worth approximately one-third the price of alfalfa hay.
While this gives you a place to start, you also need to keep in mind some likely discounts to feed value, including the condition of drought-stressed corn. According to University of Wisconsin researchers, if droughty corn is estimated to yield 20 to 40 bushels per acre, the feed value typically would be adjusted to 90 to 100 percent of the price of normal corn silage. If the yields are estimated in the range of 0 to 20 bushels per acre, the feed value would be 80 to 90 percent of the price of normal corn silage. And if the stalks are short and barren, then multiply the price by 70 to 80 percent.
If the buyer is responsible for harvesting, then use the custom farm rates for your state as a guide to establish credit toward the final payment.
For more information, visit NDSU Extension Service publication “What is the Value of a Standing Corn Crop for Silage?” online at http://www.ag.ndsu.edu/pubs/plantsci/rowcrops/ec1343.pdf.