Submitted to: Grassland International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/8/1997
Publication Date: N/A
Interpretive Summary: Double cropping of no-till annual crops provides an economic incentive and a degree of stabilization in the Coastal Plains and Piedmont regions of the Southeastern USA. A second crop frequently no-till seeded following small grains is sorghum for silage production. Tropical corn planted on June 15 (after small grain is harvested) showed high yield potential of 8.6 6tons of dry matter per acre when harvested in October as silage. The sorghum crop it would displace yielded only 3.8 to 4.6 tons of dry matter per acre. The tropical corn had <50% as much grain as an adapted temperate corn with cell wall concentrations similar to the sorghums. These forages were found to give similar dry matter intake when fed to steers. Tropical corn had a similar dry matter digestibility to intermediate sorghum, but a lower digestibility than a forage-type sorghum. The no-till planting of tropical corn resulted in a 105% increase in silage yield over the average of the sorghums without adversely altering silage dry matter intake. Tropical corn provides a high yielding alternative to sorghum in double cropping systems.
Technical Abstract: This study compared the yield potential and inherent nutritive value and quality of tropical corn [Zea mays L.] with temperate corn and two forage sorghums [Sorghum bicolor (L.) Moench] for use in multiple cropping systems. Tropical corn showed high dry matter yield potential (19.3 Mg/ha) compared with a selected temperate corn (14.7 Mg/ha) or with an intermediate (8.5 Mg/ha) or taller growing forage-type sorghum (10.3 Mg/ha). Neutral detergent fiber concentration (g/kg) was lower for temperate corn (330) than for tropical (548) corn which had a concentration similar to the intermediate (497) and forage-type sorghums (543). Dry matter intake was similar among silage (1.83 kg/100 kg body weight) but apparent dry matter digestion was higher (P=0.01) for temperate corn (64.0%) vs. Tropical corn (59.8%). Tropical corn had similar digestion values to intermediate sorghum silage (61.4%) but lower than forage sorghum (64.5%).