Purdue University Department of Agronomy

Corny News Network

Published 10 Oct 2008
URL: http://www.kingcorn.org/news/articles.08/StoverNutrients-1010.html

Corn Stover Baling - Phosphorus and Potassium Removal

Jim Camberato
Agronomy Dept., Purdue Univ.
West Lafayette, IN 47907-2054
Email address: jcambera at purdue.edu

orn stover baling removes valuable crop nutrients from the field. The amount and value of phosphorus (P) and potassium (K) in stover clearly should be considered a cost of stover baling. Other essential plant nutrients, such as nitrogen, calcium, magnesium sulfur, and the micronutrient are removed in the stover and may be figured into the nutrient cost of stover baling, especially in low nutrient soils and with long-term stover removal.

The amount of dry stover produced by a corn crop is approximately equal to the weight of grain at 15.5% moisture. Therefore, a 150 bushel per acre corn crop would leave about 4 tons of stover in the field. The usual assumption is that about 60% of the stover is gathered, approximately 2.5 tons per acre.

Corn stover contains about 3.6 lb P2O5 and 20 lb K2O on a per ton basis (based on stover concentrations of 0.18% P2O5 and 0.99% K2O). The 2.5 tons per acre removed from a field producing 150 bushels per acre contains about 9 pounds of P2O5 and 50 pounds of K2O. The value of these nutrients at current prices ($0.75 per pound of P2O5 or K2O) is about $44 per acre or $18 per ton of stover.

Crop residue is not only an important recyclable source of crop nutrients, it also helps reduce soil erosion and replenishes soil organic matter. Soil organic matter is responsible for many soil quality characteristics, such as soil structure, porosity, drainage, aeration, and water holding capacity. Corn stover removal eventually will lead to reduced soil quality through a reduction in soil organic matter. Compaction during stover removal is another factor that may reduce soil quality and should be minimized.

Fig. 1. Don't overlook the lost value of phosphorus and potassium when baling cornstalks.