Wednesday, November 15, 2006

Post-harvest Affects on Kentucky Bluegrass Forage Nutrient Composition.

John Holman1, Carl Hunt2, and Donn Thill2. (1) Kansas State University, SW Research and Extension Center, 4500 East Mary Street, Garden City, KS 67846-9132, (2) University of Idaho, Po Box 442330, Moscow, ID 83844-2330

It is unknown if combining, baling, and delayed baling affect the post-harvest residue forage composition of Kentucky bluegrass grown for seed.  Two experiments evaluated these effects on Kentucky bluegrass crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), lignin, and in-vitro true digestibility (IVTD).  In the first experiment, forage composition of the variety Kenblue was measured at swathing, before and after combining, and after baling in 2004 and 2005.  In the second experiment, forage composition was measured at 0, 2, 4, 6, 8, 11, 14, 17, 20, and 23 days after seed harvest for four varieties (Kenblue, Ascot, Touchdown, and Limousine) in 2003 and 2004.  Data were analyzed using mixed model analysis of variance with blocks and years as random effects, and treatments as fixed effects.  Treatment effects were declared significant at P ≤ 0.05.  In the first experiment, contrast statements were used to compare forage composition between swathing and before combining, before combining and after combining, and after combining and after baling.  In the second experiment, regression analysis was used to determine forage composition change with time.  In the first experiment, Kenblue forage composition averaged 6.2% CP, 33.2% ADF, 64.7% NDF, 7.2% lignin, and 54.4% IVTD on a dry matter basis at swathing.  The only forage composition changes were a 12.8% decrease in crude protein, a 7.0% decrease in IVTD, a 7.9% increase in ADF, and a 7.3% increase in NDF between swathing and before combining.  In the second experiment, forage composition was not affected by variety and averaged 6.3% CP, 33.9% ADF, 64.8% NDF, 3.8% lignin, and 59.6% IVTD on a dry matter basis at day 0.  Neutral detergent fiber increased 6.4%, ADF increased 3.3%, IVTD decreased 4.4%, and lignin and crude protein were not affected between 0 and 23 days after seed harvest. 

Handout (.pdf format, 227.0 kb)