Defoliation Management of Bahiagrass Germplasm Affects Cover and Persistence-Related Responses
- S. M. Interrantea,
- L. E. Sollenberger *b,
- A. R. Blountc,
- S. W. Colemand,
- U. R. Whitee and
- K. Liub
- a The Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401
b Agronomy Dep., Univ. of Florida, Gainesville, FL 32611-0500
c North Florida Research and Education Center, Marianna, FL 32446
d USDA-ARS Subtropical Agricultural Research Station, Brooksville, FL 34601-4672
e Natural Resource Conservation Service, Wauchula, FL 33873
Bahiagrass (Paspalum notatum Flügge) cultivars are valued for their persistence under grazing and low management inputs. However, they are daylength-sensitive and have minimal cool-season production, resulting in high winter feeding costs in forage-based livestock systems. New germplasm is less daylength-sensitive, possesses greater cold tolerance, and is more productive during the cool season, but its persistence under defoliation is unknown. A field experiment quantified cover and persistence-related responses of photoperiod-sensitive bahiagrass (diploids ‘Pensacola’ and ‘Tifton 9’ and tetraploids ‘Argentine’ and Tifton 7) and a less photoperiod-sensitive, cold-adapted (PCA) diploid bahiagrass (Cycle 4) at two stubble heights (4 and 8 cm) and two harvest frequencies (7 and 21 d). Argentine cover was unaffected by defoliation treatments, but harvesting every 7 d to 4 cm for 3 yr resulted in <40% cover for both Tifton 9 and Cycle 4. Averaging over defoliation treatments, stem base mass of Pensacola and Argentine was 60% greater than Cycle 4. At 4- and 8-cm stubble heights, the advantage was 86 and 41%, respectively. When defoliated every 7 d, Pensacola and Argentine stem base mass was 125% greater than Cycle 4, while the difference was 23% for the 21-d treatment. Similar but less-pronounced responses were observed for N and total nonstructural carbohydrate (TNC) content of stem base and root + rhizome fractions. Defoliation management of PCA Cycle 4 is more critical than for Pensacola and Argentine bahiagrass, and longer regrowth intervals and taller residual heights may be required to ensure its persistence.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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