What is the value of nutrients in baled corn stalks?
The hot and dry weather this summer has had devastating impact on all dry land
crops. Many acres of corn and soybean are not going to make it, so many growers are
baling or considering baling corn stalks for hay. Some drought stressed corn may be
harvested for silage also. However, we need to remember that there is a value to
leaving the crop on the ground as a nutrient source for the next crop and as organic
matter for long-term soil quality, which is always beneficial. Crop residues contain all
plant essential nutrients, especially N, P and K. Baling stover for hay or for sale will
remove those nutrients from the field.
So, can we put a value on the baled corn stalks? We can calculate the main
nutrient value based on the nutrient content of the residue and current market prices for
N, P and K. The table below shows the estimated N, P and K value of baled corn stalks
for two different moisture contents. The nutrient contents are average values and they
vary with growth stage when harvested and with soil fertility levels. Using current
nutrient costs, the baled corn is worth nearly $40/per ton on a dry weight basis. The
value drops to $15/ton if the stalks have 60% moisture. Note that this is just the value of
the nutrients themselves, and the potential value would be higher if fertilizer application
cost is factored in.
Estimated nutrient value of baled corn stalks.
Moisture Total N P2O5 K2O N, P and K
value
% lbs/ton $/ton*
Dry Basis 0 24 8 32 37.6
As Harvested 60 9.6 3.2 12.8 15.04
* Estimate based on $0.6/lb of N, $0.5 lb of P2O5, and $0.6/lb of K2O
If the crop residues are left in the field, all nutrients and organic matter would be
returned to the soil. However, not all the nutrients are going to be available to the
following crop because organic matter must be decomposed before nutrients become
available. Conservative estimates suggest at least 60% of N and 80% of P and K will be
available for the next crop. Consider the nutrient value and organic benefits when baling
a failed corn crop.
Hailin Zhang
Hailin.