In recent years cattlemen have become more interested in harvesting and utilizing corn residue. Factors contributing to this greater interest have included higher hay and feed costs, more acres in row crops and the availability of large balers and stackers that can effectively harvest corn residue.
Now an important new situation exists. Producers who participate in U.S.D.A. programs now must maintain 30% ground residue cover until after the succeeding crop has been planted the following spring. This plant residue helps reduce soil erosion during the winter and through to the establishment of the new crop. If significant corn residue is removed, a fall planted cover crop or modifications in type of spring tillage and planting may be necessary to preserve the needed 30% ground cover. Conservation provisions in the 1985 and 1990 farm bills require compliance in order for growers to participate in Crop Support Payments, Storage Loans, Federal Crop Insurance, FHA loans and other Federal programs.
Cattle grazing of corn residue may still be possible since animals seldom consume more than 20-25% of the stover. A 100 bushel/acre grain yield should result in 6000 lbs. field residue with 9000 lbs. for a 150 bushel grain crop. Sufficient residue should remain over winter to provide necessary spring cover. This is especially true where adequate stands of taller growing corn hybrids are utilized and cattle grazing is limited to consumption of unharvested grain, leaves and husks. These tender plant tissues generally decompose rapidly so they are not present in large quantities the following spring.
If residue cover is substantially reduced by whatever means, including grazing, baling, stacking and ensiling, the producer will need to promptly seed a rye or wheat cover crop to protect the soil through to planting. Remember, however, the final step is to maintain 30% surface residue cover until after planting the new crop the next spring.
Approximately 50 percent of the weight of the total corn plant is residue, consisting of stalk, leaf, cob and husk. Table I indicates the dry matter distribution in corn residue at or immediately following corn harvest. Note the stalk contains the highest level of moisture and is one-half of the dry matter weight of the total residue material.
Table I. Dry Matter Distribution in Corn Residue | ||
|---|---|---|
| Corn Residue | % Moisture | % of Residue D.M. Basis |
| Stalk | 70-75 | 50 |
| Leaf | 20-25 | 20 |
| Cob | 50-55 | 20 |
| Husk | 45-50 | 10 |
Three basic methods of harvesting corn residue are grazing, stacking or baling and ensiling.
Grazing or gleaning of corn residue in fields with livestock has been an accepted practice by many livestock producers. One acre of corn residue will yield approximately 60 animal unit grazing days. This means that one acre of corn residue will provide 60 days of grazing for a 1,000 pound animal, or 30 days for two animals, etc. Livestock will selectively graze the most palatable portions of the residue first; the grain, leaves and husks and then the cobs and stalks. Generally animal grazing will leave 75 to 80% of total residue in the field, especially if animals are rotated to new areas before appreciable cob and stalk material is consumed.
Suggestions for optimum grazing of corn residue:
Problems of grazing:
The potential for stacking or baling corn residue has been made possible in recent years by the development of fast, efficient field stackers and large round balers. The field stackers may be of direct flail type pickup, while for use of the large round baler and for some using the stackers, the residue will need to be windrowed. This system results in removal of more corn residue than from grazing.
Suggestions for stacking or baling corn residue:
Problems of stacking or baling:
Harvesting and storing corn residue as silage will result in the retrieval of the highest percent of the material from the field. Dry matter yields of 2-3 tons per acre may be expected. Livestock dry matter intake and palatability of the silage is higher than that of the residue stacks or bales. Forage harvesters with a flail pickup are used for this system.
Suggestions for ensiling:
Problems of ensiling:
With the reduced acreages of small grain, straw may be in short supply. Dry corn residue may be used for bedding. The residue should dry in the field to as low a level as possible prior to harvest.
Corn residue is not a high quality feed. It is low in energy, protein and digestibility. Animal scientists indicate unsupplemented or untreated corn crop residue is not adequate to maintain a beef brood cow year-round. Corn residue barely supplies sufficient energy to maintain a beef cow during early pregnancy and does not supply adequate amounts of protein, phosphorus and vitamin A. Grazeable or harvested crop residues should be used with beef cows in the middle trimester of pregnancy. This assumes average or better cow body condition. Cows with twin calves need additional supplementation.
Table II indicates the average composition of corn residue and corn residue silage.
Table II. Crop Residue Composition | ||
|---|---|---|
| Corn Residue | Corn Residue Silage | |
| Estimated TDN % | 45.0 | 50.0 |
| Crude Protein % | 4.0 | 5.3 |
| Calcium % | 0.37 | 0.44 |
| Phosphorus % | 0.12 | 0.14 |
| Vitamin A, IU/lb. | 0.0 | 0.0 |
Livestock producers must be aware of the nutritional value of corn residue and its limitations in feed value. Producers also must be aware of the necessity to maintain adequate residue cover or planting of a cover crop to meet conservation guidelines. Some agronomists for years have questioned the wisdom of repeated total removal of corn stover because a good management program that leaves crop residue on the surface promotes good soil structure, aggregation, and decreases the potential for soil erosion by water and wind.
Written by:
Donald K. Myers, Extension Agronomist Emeritus, Forages
Revised by:
John F. Underwood, District Specialist, Agronomy
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