The Value of Corn Residue
by Greg Stewart, OMAFRA Corn Specialist
Is the value of selling corn residues more than the value of the nutrients lost?
Ontario’s energy providers are evaluating corn residue for bioenergy production. Although opportunities may emerge for Ontario producers to supply corn residues to diversify their income, the value of the residue should be considered before signing any contract.
Corn residues have potential for ligno-cellulosic conversion to produce ethanol or to be sold as an energy source for direct combustion. To some, corn residues may be considered a waste, however research shows removing corn residue from the soil removes nutrients and reduces soil productivity over the long term [1. Blanco-Canqui, 2009].
Estimated nutrient loss / US ton residue removal
The actual nutrient loss from residue removal is difficult to predict. Dr. Paul Fixen, from the International Plant Nutrition Institute, has identified large variation in the nutrient content of residues after harvest due to; foliar leaching during crop senescence, the extent of weathering in the field, and harvest techniques. For example, 40% residue removal would increase nutrient removal from the soil (N by 20%, P2O5 by 14% and K2O by 110%) for an average 150 bu/ac corn crop.
Table 1 shows the average lbs/dry US ton of N, P and K that are removed when residues are harvested for biomass, including both U.S. and Canada sources [2. Fixen, 2007]
| Table 1. Nutrient content of corn residue | |||
| N | P2O5 | K2O | |
| 8 estimates of typical corn residue nutrient concentrations | 9 - 22 | 3.6 - 8.0 | 16 - 46.5 |
| Average | 19 | 5.7 | 32 |
Cost to replace lost nutrients
In a second study, Dr. Reed Hoskinson, from the Idaho National Laboratory calculated the short term fertility replacement requirements for corn residue removal (cut height 15.5 inches) to be: N at 33.5 lb/acres, P at 3.3 lbs/acre and K at 28.6 lbs/acre. The cost estimate for this scenario was valued at $21.60/acre. Of course it must be noted that the actual replacement costs are directly connected to the amount of residue removed and fertilizer prices. In some cases the costs to replace nutrients may vary by 3-4 times depending on price fluctuations in fertilizer. Including compensation for Ca, Mg, and micronutrients (Cu, Fe, Mn, and Zn) would increase these costs further.
Although nutrients removed from the corn residues can be replaced post harvest, there are other logistical issues to be considered. There are other management and economical considerations like residue collection method, additional passes in the field, residue moisture content, drying costs, type and quantity of storage facilities and transportation costs. These logistics will require local solutions, and will have a large influence on the practically of using corn residue for biomass combustion for energy production in Ontario.
Residue removal for the bioeconomy must carefully be considered for its impacts on soil fertility. Producers will need to monitor soil fertility to prevent nutrient deficiencies in the long term and must be prepared to require additional N, P and K fertilizers to compensate for the loss when removing crop residues.
References
1. Corn Residue Removal for Expanded Uses Reduces Soil Fertility and Structural Stability. Blanco-Canqui, 2009. Soil Science Society of America Journal [0361-5995] vol:73 iss:2 pg:418 -426
2. Potential Biofuels Influence on the Fertilizer Market. Paul E. Fixen. International Plant Nutrition Institute. 2007. www.ipni.net/ppiweb/.../Fluid%20Forum%20Biofuels%20Impact.pdf
3. Engineering, nutrient removal, and feedstock conversion evaluations of four corn residue harvest scenarios. Reed L. Hoskinson, 2007. Biomass and Bioenergy. vol:31 pg:126–136.
This article has been created on behalf of the IFAO and the Advancing Innovative and Sustainable Cropping Systems in Ontario Project funded by the Agricultural Adaptation Council.
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