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Title: FORAGE NUTRITIVE VALUE IN AN EMULATED SILVOPASTURE

Author
item BUERGLER, A - VIRGINIA TECH
item FIKE, J - VIRGINIA TECH
item BURGER, J - VIRGINIA TECH
item Feldhake, Charles
item MCKENNA, J - VIRGINIA TECH
item TEUTSCH, C - VIRGINIA TECH

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2006
Publication Date: 6/10/2006
Citation: Buergler, A.L., Fike, J.H., Burger, J.A., Feldhake, C.M., Mckenna, J.R., Teutsch, C.D. 2006. Forage Nutritive Value in an Emulated Silvopasture. Agronomy Journal 98:1265-1273.

Interpretive Summary: Farms in the Appalachian Region typically have about half of their acreage occupied by variable density trees or forest. There is little information available for farmers on how to increase the economic return from these acres by incorporating them into animal production systems. We evaluated forage quality across black walnut and honey locust tree density gradients in order to determine how forage under these species might best be managed as a component of farm grazing systems. Animal-available energy decreased with tree density but forage mineral content increased. Crude protein was generally higher under honey locust than under black walnut. The results suggest forages under trees can supplement open-pasture grazing when appropriately managed in order to increase the overall capacity of the farm system. This work provides a useful tool for scientists from which to further refine optimal grazing systems within the Appalachian Region. It also provides a base for advisors to help farmers better utilize some of their tree impacted land. It will benefit rural areas by increasing the profitability of small farms thus improving the quality of life in small communities across the economically depressed Appalachia Region.

Technical Abstract: Incorporating trees into pastures may alter forage nutritive value. The objective of this study was to determine nutritive value in response to trees and slope position in an emulated (no animals) silvopasture. In 1995, black walnut (Juglans nigra L.) and honey locust (Gleditisia triacanthos L.) trees were planted within plots (r = 3) of predominantly tall fescue (Festuca arundinacea Schreb.) pasture. Soils on the site, (Unison and Braddock) are clayey, mixed mesic Typic Hapludults, well drained, with moderately steep slopes (10-25%). Trees were planted down slopes in rows to create low, medium, and high tree densities at shoulder, mid, and toe slope positions. Sampling sites (n = 54) under field treatment combinations were harvested May, June, and July in 2002 and 2003. Concentrations of neutral and acid detergent fiber (NDF, ADF), acid detergent lignin (ADL), crude protein (CP), total non-structural carbohydrate (TNC) and Ca, P, Mg, and K were determined. Few differences due to treatment were observed for NDF and ADF concentrations. Concentrations of TNC decreased with greater tree density and appeared to follow tree leaf dynamics. Crude protein concentrations were typically greater under honey locust trees. Forage mineral concentrations frequently were greater with increased tree density. Trees appear to have both positive and negative effects on forage nutritive value, and their effects on animal performance warrants further research.