Farm Progress

Extension Crop Connection: With harvest underway in Nebraska, consider corn residue removal through baling or grazing this season.

Daren Redfearn

October 8, 2018

4 Min Read
EXCESSIVE RESIDUE: In Nebraska, it's common to see cattle grazing cornstalks or baling equipment harvesting the residue for feeding.

Over the past 50 years, corn grain production has increased around 2 bushels per acre per year. At the same time, the amount of corn residue has also increased since grain production and residue production are related. For each 40 bushels of corn, there is about 1 ton of corn residue. That means that production environments for 180 to 200 bushels of corn grain per acre can also have 4.5 to 5 tons of residue per acre, and about 7 tons of residue per acre for grain yields approaching 300 bushels per acre.

Residue levels in high-yielding environments present several production challenges in both continuous corn and corn-soybean rotations. The most common issues are physical hindrances at planting due to residue volume, reduced crop establishment due to either poor planting or competition from excessive residue, increased insect and disease pressure, and a predictable reduction in yield.

Doing nothing is usually not a good option for managing excessive corn residue. Methods to manage excessive residue include tillage or shredding. In Nebraska, it is common to see cattle grazing corn residue or baling equipment mechanically harvesting residue for feeding later.

However, there are reasons for not baling corn residue. These include the potential for increased soil compaction from harvesting equipment, decreased soil organic matter, wind and water erosion, and loss of valuable plant nutrients.

Grazing corn residue, at low to moderate stocking rates, does not appear to cause negative effects on crop growth due to soil compaction. In fact, any soil compaction resulting from proper grazing is limited to the surface and is short-lived from natural freeze-thaw cycles.

Also, reduced soil organic matter, increased erosion and reduced nutrient availability have not been reported under moderate grazing. Residue removal by baling or grazing each present special considerations and challenges.

Baling corn residue
Good management practices for baling corn residue include several factors. Two simple questions can be asked as a guide for baling corn residue. First, is the field susceptible to erosion? Corn residue should not be harvested if the slope in the field is greater than 4% (water erosion), or if the field has soil types or is in a region prone to wind erosion.

Secondly, can residue removal be supported? This relates to biomass production. If grain yields are considerably less than 180 bushels per acre, regularly harvesting corn residue will most likely decrease the long-term supply of soil organic matter.

One common cost associated with crop residue harvest is the value of the nutrients removed. Crop residue components differ in nutrient concentration, with most of the nutrients concentrated in leaves and husks. The concentration of nutrients in crop residues can also vary with season, management practice, time of harvest and location.

Common management practices for baling corn residue in the western Corn Belt include:

 mechanically harvesting no more than 40% of the residue

 baling corn residue no more than three out of every four years in continuous corn systems

 baling residue no more than two years out of five years corn is grown in corn-soybean systems

Surface applied manure or cover crops can help minimize negative effects of residue removal.

Grazing residue
If baling is not an option, is grazing corn residue a reasonable management option to increase the amount and rate of corn residue breakdown?

Grazing corn residues isn't a new practice, but some producers are concerned about negative effects on the following crop. University of Nebraska-Lincoln recommendations for establishing corn residue stocking rates are based on 50% utilization of leaves and husks (8 pounds per bushel or 20% of the total corn residue).

Some additional corn residue would disappear through trampling and wind loss, but there should be no increased erosion risks if 40% to 50% of the corn residue was removed through grazing.

A 16-year corn-soybean rotation study conducted in Nebraska investigated long-term yield effects on corn and soybeans from grazing corn residue during fall or spring. When corn residues were grazed at proper stocking rates (15% residue removal), crop production after grazing was not reduced. In fact, small, positive impacts of grazing corn residue on subsequent soybean yield occurred.

In a recent survey conducted by the University of Nebraska-Lincoln, 17% of responding crop producers listed lack of available cattle as the reason for not grazing corn residue. Other factors, including lack of fencing and water availability, can also be hurdles.

UNL's Crop Residue Exchange was developed to increase the use of crop residue for livestock grazing by helping crop producers make their crop residue more available to cattle producers and develop mutually beneficial grazing agreements.

The Crop Residue Exchange is an interactive, online tool designed to help farmers and cattle producers connect and develop mutually beneficial agreements for grazing using crop residues. This online exchange serves as a way for corn and other crop producers to market their crop residue to cattle producers, and is available at cropresidueexchange.unl.edu.

Redfearn is a Nebraska Extension forage and crop residue specialist.

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