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United States Department of Agriculture

Agricultural Research Service

Title: Influence of Root Removal on Regrowth and Forage Quality of Greenhouse-Grown Eastern Gamagrass

Authors
item Rhoden, Errol - TUSKEGEE UNIV
item Reeves Iii, James
item Krizek, Donald
item Ritchie, Jerry
item Foy, Charles - COLLABORATOR W/ CSL

Submitted to: Eastern Native Grass Symposium
Publication Type: Proceedings
Publication Acceptance Date: May 1, 2000
Publication Date: July 1, 2000
Citation: RHODEN, E.G., REEVES III, J.B., KRIZEK, D.T., RITCHIE, J.C., FOY, C.D. INFLUENCE OF ROOT REMOVAL ON REGROWTH AND FORAGE QUALITY OF GREENHOUSE-GROWN EASTERN GAMAGRASS. EASTERN NATIVE GRASS SYMPOSIUM. 2000.

Interpretive Summary: Trimming roots of eastern gamagrass plants by 0, 25%, and 50% at the time of transplanting had a negative effect on subsequent regrowth of shoots, particularly when 50% of the roots were removed. This was generally reflected in an increase in the number of senescent leaves, a decrease in the number of tillers, and a reduction in the dry weight of forage collected. Despite these reductions in vegetative growth, there was little or no effect of root removal or time of harvest on forage quality. A slight increase in lignin content and slight decreases in crude protein (CP), dry matter digestibility, and cell wall digestibility were obtained at the second harvest in plants that had been pruned 25%, but these constituents tended to show a reversal in values at subsequent harvests. Removal of 50% of the roots surprisingly had little or no significant effect on CP or lignin content. It appears that one of the main ways in which eastern gamagrass plants coped with the stress of root pruning was to increase the number of senescent leaves. This is rather remarkable considering that these stress effects were not reflected in a decline of forage quality of the new shoots formed. These findings demonstrate the extreme versatility of eastern gamagrass in coping with environmental stress and in being able to compensate for adverse growth conditions.

Technical Abstract: This study was conducted to determine the influence of root removal on shoot regrowth and forage quality of greenhouse-grown eastern gamagrass plants. On July 27, 1998, the root mass of 5-month old plants was pruned 25% or 50%, or left uncut, and the plants were transferred to 20cm diameter pots having a depth of 40cm. Shoots were clipped to 25cm on August 18 (H1-vegetative), September 16 (H2-vegetative), October 7 (H3-flowering), and October 28 (H4-dormat). For each harvest, height and total biomass measurements were taken on shoot regrowth, and samples were analyzed for neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, crude protein (CP), dry matter digestibility (DMD), and cell wall digestibility (CWD). Trimming roots of eastern gamagrass plants at the time of transplanting had a negative effect on subsequent regrowth of shoots, particularly when 50% of the roots were removed. This was generally reflected in an increase in the number of senescent leaves, a decrease in the number of tillers, and in a reduction in the dry weight of forage collected. Despite these reductions in vegetative growth, root removal had no significant effect on NDF or ADF and little or no effect on DMD or CWD at H1-H4. Content of lignin and CP was variable, depending on the extent of root removal and the date of harvest. CP content of the forage samples ranged from 14% to nearly 20%. The ability of eastern gamagrass plants to cope with the stress of root pruning without altering the quality of forage demonstrates the resilience of this species for adapting to adverse environmental conditions.

Last Modified: 10/25/2014
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