A FOUR-YEAR STUDY ON YIELD AND ROOT DEVELOPMENT OF EASTERN GAMAGRASS GROWN ON AN ACID, COMPACT SOIL

Authors: Krizek, Donald; Ritchie, Jerry; Sadeghi, Ali; RHODEN, ERROL - TUSKEGEE UNIV; DAVIS, JOHN - NRCS, USDA; Camp, Mary; FOY, CHARLES - USDA,ARS (RETIRED)

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2002
Publication Date: 2/1/2003
Citation: KRIZEK, D.T., RITCHIE, J.C., SADEGHI, A.M., RHODEN, E.G., DAVIS, J.R., CAMP, M.J., FOY, C.D. A FOUR-YEAR STUDY ON YIELD AND ROOT DEVELOPMENT OF EASTERN GAMAGRASS GROWN ON AN ACID, COMPACT SOIL. COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS. 2003. V. 34(3-4). P. 457-480.

Interpretive Summary: It has been estimated that 39% of the soils in the mid-Atlantic region have root restriction factors with 50-100 cm of the soil surface. Species are needed that are adapted to such sites. Eastern gamagrass is a perennial, warm-season grass that has been called "Queen of the Grasses" because of its rapid growth rate and extreme palatability as a forage crop. It has been shown to have promise in soil conservation as a grass hedge because o its fibrous root system and ability to tolerate waterlogged soils. The present study was conducted to determine the adaptation of eastern gamagrass to aluminum-toxic, acid, compact soils on a site at the Beltsville Agricultural Research Center previously occupied by tall fescue. Despite restricted soil conditions imposed by shallow top soil, strong acidity, high bulk density, and a limited moisture supply, eastern gamagrass plants produced high forage yields during the four-year period of f1997-2000. The silt content and bulk density of the soil and the distribution of rainfall appeared to be important factors in determining yield. The acidity of the soil was only of minor importance. This research indicates that eastern gamagrass is ideally suited for reclaiming acid, compact soils since roots of this species can penetrate compact clay pans that serve as barriers to roots of corn and other crops. Since eastern gamagrass also produces high biomass yield of a high quality forage, eastern gamagrass is an ideal grass for the management of poor soils while producing abundant forage for livestock. These findings should be of interest to farmers interested in growing plants on marginal lands.

Technical Abstract: A field study was conducted from 1997 to 2000 to determine the yield of 'Pete' eastern gamagrass [Tripsacum dactyloides (L.) L.] grown on an acid, compact soil at the Beltsville Agricultural Research Center. Total yield from two cuttings in 1997, 1998, and 2000 averaged 3801, 4469, and 6007 kg/ha, respectively, despite drought conditions during those years. A single cutting in July 1999 averaged 1981 kg/ha. In general, yields varie with position on the slope, bulk density, and depth of the topsoil, but not with pH. Average yield was generally lowest at the top of the slope where the depth of the Ap horizon was relatively shallow and the soil was strongly acid (pH 4.3 - 4.4). The silt content and bulk density of the soil and the distribution of rainfall appeared to be important determinants of yield. Eastern gamagrass at sites 4 to 6 at the top of the slope generally had a low pH (4.3 - 4.4), high penetrometer resistance, and high bulk density. Significant differences in yield were found between sites, year, and harvest date. Penetrometer readings were lower between rows than within rows at 5 cm depth. There was no relationship between bulk density and penetrometer readings but forage yields appeared to be related to bulk density. Dry weight of roots was reduced by increasing bulk density and at depths below 15 cm. Despite stress imposed by shallow top soil, low pH, and high bulk density, eastern gamagrass survived deficits in soil moisture during 1997-2000. These findings indicate that eastern gamagrass is ideally suited for reclamation of acid, compact soils and for producing high yields of forage on marginal lands.