August 22, 2008

A recently published NebGuide, Harvesting Crop Residues, G1846, addresses the question of how much value you lose when removing corn stalks from the field. It covers the implications of stover harvest for the value of nutrients removed, maintenance of soil organic matter and soil productivity, wind and water erosion, and runoff and evaporation. Tillage and cropping systems also are important considerations. 

The amount of crop residue produced is related to grain production. Approximately 1 ton of crop residue (at 10% moisture) is produced with 40 bushels of corn or grain sorghum (56 lb/bu at 15.5%), 30 bushels of soybean, and 20 bushels of wheat. One of the easiest costs to estimate relative to crop residue harvest is the value of the nutrients removed. The concentration of nutrients in crop residues varies with season, management practice, time of harvest, and location. In addition, crop residue components differ in nutrient concentration, with most elements concentrated more in leaves and husks than stalks. The typical nutrient content for corn or sorghum is about 17 lb nitrogen, 4 lb P₂O₅, 50 lb K₂O, and 3 lb sulfur per ton of dry harvested residue.

NebGuide 1846 contains a worksheet for calculating the total cost of harvesting crop residue.  Since its publication, the costs of several nutrients have changed significantly.  The chart below represents figures that may be more accurate at this time.

G1846 is available online at http://www.ianrpubs.unl.edu/sendIt/g1846.pdf

Charles Wortmann
Extension Nutrient Management Specialist
Charles Shapiro
Extension Soils Specialist