By Todd Whitney
Fair pricing of drought-stressed forage can be a challenge when harvest costs are higher per ton along with lower yields and reduced energy values due to drought.
Under normal conditions, grain content in a field is about 52% of the total biomass. So, when droughty corn fields are earless; the UNL rule of thumb: multiplying the corn grain value per bushel times 7.65 to equal the forage value per ton might need adjustment. For example, if the dry matter is only 30% versus the standard 35%; and field grain content is 40% verses normal 52%; then, the fair multiplier tonnage price would be 5 times the grain price instead of 7.65.
An alternative pricing method might be using hay values adjusted for moisture. However, drought many times drives hay prices higher than comparative silage prices. So, the normal rule of thumb: one ton of corn silage substituting for 1/3 the price of alfalfa hay per ton may also overvalue droughty forage.
The bottom line is that droughty crops have less TDN (total digestible nutrients) than normal forage, so ‘rule of thumb pricing’ should be slightly adjusted. Actual field sample nutrient content testing (regarding standing forage for grazing, greenchop or silage) is the fairest method for both the buyer and seller.
For example, if we use 72% TDN as normal for corn silage, then a droughty 60% TDN crop adjustment factor would equal 0.83 (60/72) or about 17% less value. Buyers bear the risk of over-estimating the value of drought-stressed corn which often has wetter content and less value than normal corn harvests.
Further value pricing might be improved by using free silage valuing spreadsheets on Nebraska Extension; Iowa State or South Dakota State University websites.