Corn

Zea mays L.

Symbol:

ZEMA

Group:

Monocot

Family:

Poaceae Barnhart

Description:

An erect, fast growing, warm-season annual commonly growing to 6.5 to > 9 feet (2-3m). As a forage crop, corn can be green-shopped, made into silage or directly grazed by animals. Corn makes excellent forage due to its rapid growth, high yields, high-energy, and fiber quality, and diversity of utilization. Silage corn is high in sugars that enhances rapid silage fermentation, so often little or no requirements for additives to assist the ensiling process. Stover dry leaves, husks, and stocks, remaining from corn grain harvest, is a major source of fall and winter grazing feed for ruminants, when soils are dry or frozen.

Corn silage serves as a high-energy forage for year-round dairy cow production, usually in total mixed rations (TMR's). With its relatively high-energy (starch) content, corn silage is also well adapted for inclusion in low-cost cattle fattening rations. Silage corn requires less labor per ton to produce, possesses fewer anti-quality traits, but is also relatively more expensive to grow than many other forage crops. The broad genetic base of corn permits adaptability and interactions within the widely diverse environments where the crop is grown. It can extend the harvest period for the entire corn acreage and provide an opportunity for salvage of stressed or damaged cornfields. It can also efficiently recycle plant nutrients, especially large amounts of N and K.

Uses:

Silage

Identification Characteristics

Type:

Grass

Climate and Soil Suitability Zones

Climate Tolerances:

Corn requires soil temperatures at or above 50°F (10°C) for germination and development of the young seedling. Optimum growth temperature is approximately 86°F (30°C). Tassle development is reduced at temperatures above 82.4°F (28°C). In dryland farmin systems, corn is generally not grown in areas receiving less than 25 in (60 cm) of annual precipitation. For high yields, growing season precipitation of 18 to 20 inches (45 to 50 cm) is needed.

Soil Tolerances:

Corn grows best in moderately well-drained soils, but will tolerate somewhat poorly-drained to excessively drained conditions. It will only tolerate short periods of flooding. Suited to moderately acidic soils (pH 5.6-7.3). Intolerant of Aluminum (persistence reduced at 0.5 ppm Al3+ and pH 4.2). Moderately sensitive to salinity, 1.5-3dS/m (millimhos,cm).

Cultivars

To maximize corn silage yield potential, select hybrids with a relative maturity rating up to 10 days longer than a full-season grain hybrid for your area. These hybrids often have a 2 to 4 ton/acre (4.48-9 metric ton/ha) yield advantage over standard maturity hybrids. However, later-maturing hybrids are not appropriate where the crop may be harvested for grain, where early silage is desired, or where wet soils may interfere with harvest. Forage quality varies among hybrids. Many seed corn companies are characterizing their hybrids with respect to whole plant digestibility, fiber digestibility, and starch digestibility. Selecting an appropriate hybrid is based first on relative crop maturity (RCM). This ensures that the hybrid is matched to the length of the growing season. Other considerations are leafiness (leafy hybrids contain a gene that results in an increase in the leaf content of the silage) and lignin content.

Quality and Antiquality Factors

Quality Factors:

Depending on the type of livestock used, producers may have to supplement to compensate for lower protein levels of corn silage or grazed corn.

Anti-quality Factors:

Mycotoxins have long been a concern to livestock producers when environmental conditions during the growing season were conducive to mold growth on the field crop. Mycotoxins are now more frequently being associated with crops like corn silage that include not just grain, but are now more frequently being associated with crops like corn silage that include not just grain but a high percentage of stalks and stover. Management practices that can help to minimize the effects of molds and mycotoxins include:

A balanced soil fertility program.
Hybrid selection based on disease resistance, relative maturity, and insect resistance.
Tillage and crop rotation to non-susceptible crops.
Control of leaf diseases through cultivar selection and fungicides.
Optimum harvest timing and optimum moisture. The longer th crop stands in the fields, the more opportunity for mold and mycotoxin development.
Transgenic hybrids may reduce the risk of molds and mycotoxins.