ARS | Publication request: A THREE YEAR STUDY ON YIELD AND ROOT DEVELOPMENT OF EASTERN GAMAGRASS STANDS GROWN ON A RESTRICTED SOIL

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 2000
Publication Date: N/A

Technical Abstract: A three-year field study (1997 to 1999) was conducted to determine the response of eastern gamagrass (cv. Pete) to pH, bulk density, and depth of topsoil on six sites of a loam soil. Despite severe drought in all three years, total yield from two cuttings ranged from 2.4 to 6.0 Mg/ha in 1997 and 2.9 to 7.1 Mg/ha in 1998. In 1999, only one cutting was obtained in July, which yielded 1.1 to 3.5 Mg/ha. In general, yields varied with position on the slope, bulk density, and depth of topsoil, but not with pH. Sites at the base of the slope out-yielded those at the top and tended to have lower bulk density, lower penetrometer resistance (PR), and greater topsoil depth. Overall, bulk density increased with depth; the average bulk density of the six sites at 0-15,15-30, and 30-45 cm was 1.3, 1.6 and 1.7 g/cm3, respectively. Root dry weights were reduced at depths below 15 cm, where bulk density was the highest. PR readings at site 1 (plowed) averaged 2.2 MPa, while the averages at the other five sites (no-till planted) ranged from 4.3 to 4.8 MPa. PR readings were lower within rows than between rows at 5 cm depth. Forage yield was not closely related to PR. The capacity of eastern gamagrass to survive moisture stress may be attributed to its ability to develop deep penetrating roots in restricted soils early in the season, thereby, providing a drought-avoidance mechanism.