Eduardo I. Alava1, Yoana Newman2, Lynn E. Sollenberger1, Diane Rowland3, Charles Staples4 and Leonardo Ortega5, (1)Agronomy Department, University of Florida, Gainesville, FL (2)University of Florida, Gainesville, FL (3)Agronomy, Univ. of Florida, Gainesville, FL (4)Animal Sciences, University of Florida, Gainesville, FL (5)National Mango Board, Gainesville, FL
Spring transition from annual ryegrass to warm-season perennial grasses can be troublesome and inconsistent due to heat-tolerant annual ryegrass. A two year evaluation was conducted to examine the factorial combination of three ryegrass removal dates (early March, D1; mid March, D2; and late March, D3) and three removal methods [chemical, C; mechanical, M; and simulated grazing, G, plus two controls (T-85 only not overseeded, and overseeded ryegrass not removed)] on spring regrowth of Tifton 85 bermudagrass (T-85). There were interactions with year for light interception at soil level (P < 0.01). In 2011, light interception was affected by date and method (P < 0.01); highest light interception occurred with D2 (54%) followed by D1 (47%), and D3 (40%). Tifton 85 only had the highest light interception (76%), followed by chemical removal (65%), mechanical removal (49%) and simulated grazing (45%). In 2012, light interception was affected by date and method (P < 0.01). Highest light interception occurred with early removal D1 (41%) followed by D2 (35%), and D3 (31%). Tifton 85 only had the highest light interception interception (61%), followed by chemical removal (48%), simulated grazing (41%) and mechanical removal (37%). Tifton 85 rhizome mass was by affected by year (P < 0.01; 314.9 vs. 731.5 g m2 in 2011 and 2012, respectively). Removal date had an effect (P < 0.01) on Tifton 85 rhizome mass. Early removal D1 had the heaviest rhizome weight (659.9 g m2), followed by D2 (506.5 g m2) and D3 (443.5 g m2). Implications from this study show that warm spring temperature will require early removal of ryegrass to guarantee T-85 bermudagrass regrowth in the spring.