The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Wednesday, January 30, 2008 - 9:00 AM
Forage Productivity and Quality Dynamics in Southern-Pine Silvopasture Versus Open-Pasture
Uma Karki, Mary S. Goodman, and Susan E. Sladden. Agronomy and Soils, Auburn University, 202 Funchess Hall, South College Drive, Auburn University, AL 36849-5412
Silvopasture is a sustainable agroforestry practice that affords environmental and economic benefits. However, there is little information relative to forage productivity and quality dynamics in silvopasture developed from pasture. The objectives of this research were: 1) to determine the impact of N source (fertilizer-N versus legume-N) on forage productivity in silvo- versus open-pasture, and 2) to determine the impact of N source on forage quality (N and ADF) in silvo- versus open-pasture. This research was conducted from 2003 to 2007 at Americus GA (Pinus palustris Mill.) -bahiagrass (Paspalum notatum Flugge) silvopasture and adjoining bahiagrass pasture. Starting 2005, treatments included either fertilizer-N or overseeded crimson clover (Trifolium incarnatum L. ‘Dixie ’). Silvopasture forage productivity and quality were monitored in two (1.0m and 6.1m, 2003-2005) or three (1.0m, 3.5m, and 6.1m; 2006-2007) alley positions relative to the center of the tree base. Overall, the legume-N treatment produced 7% higher shoot dry matter (SDM) than fertilizer-N. Silvopasture produced 25% higher SDM in 2003; but SDM was 28% higher for open-pasture in 2007. During 2006-2007, SDM production at 3.5m was 34% and 13% higher than at 1.0m and 6.1m, respectively; 6.1m SDM was 19% higher than 1.0m SDM. Forage N concentration was 6% higher for legume-N than fertilizer-N. Forage N in silvopasture was 25% and 16% higher than in open-pasture in May and August 2006, respectively. ADF concentration was 4% higher for silvopasture than open-pasture. In silvopasture, forage N at 6.1m was 14% higher than at 1.0m in April 2007; ADF was higher at 1.0m than at 6.1m in May and June 2006. Significant spatial as well as temporal impacts on forage productivity and quality occured early in conversion of bahiagrass pasture to silvopasture. Benefits of legume addition for forage productivity and quality equaled or surpassed benefits of N fertilizer.