|Brauer, David - Dave|
Submitted to: Agroforestry Systems
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/5/2001
Publication Date: 1/1/2003
Citation: BURNER, D.M., BRAUER, D.K. 2003. HERBAGE RESPONSE TO LOBLOLLY PINE SPACING UNDER EXTENSIVE MANAGEMENT IN ARKANSAS, USA. AGROFORESTRY SYSTEMS. 57:69-77. Interpretive Summary: Farming, in particular that of smaller scale operations, have been marginally profitable in recent years due to low agricultural commodity prices. Agroforestry offers the potential of decreased risk, increased farm receipts through commodity diversification, increased agricultural sustainability, and improved utilization of natural resources. The application of pine agroforestry practices could increase farm receipts on millions of acres of marginal land in the southeast USA. However, growers interested in adopting agroforestry practices are confronted with a min-boggling array of potential tree-crop-livestock combinations, and often must make their decisions based on insufficient research data. Our objective was to assess forage productivity between rows of loblolly pine of different widths on a marginal site with no fertilizer input. Row spacing had large effects on forage productivity, especially in stands exceeding 340 trees per acre, even though trees were only six years old. These results are of interest to growers and professionals working with landowners as they provide insight into tree stand arrangements that balance tree and forage crop yield and quality on poorer agricultural sites.
Technical Abstract: Loblolly pine (Pinus taeda L.) silvopastures often are established and maintained on sites of poor soil fertility and minimal fertilizer input. Our objective was to determine whether row spacing affected yield, quality, and botanical composition of extensively managed herbage in loblolly pine early in the tree rotation. Plots were randomly located equidistant from bordering tree rows in each of eight alley width treatments that were 2.4, 3.6, 4.9, 7.3, 9.7, 12.2, 14.6 m wide, and no trees. Row spacing affected the yield, quality, and botanical composition of marginal pasture five to six years in the rotation especially at densities exceeding 840 trees/ha. Botanical composition shifted from predominantly cool-season to warm-season grasses between annual first- and second-harvests, respectively, which caused seasonal differences in several yield and quality traits. Tall fescue production appeared to be unsustainable under marginal management. Herbage yield generally increased, but quality and minerals (crude protein, IVDMD, Ca, and P) tended to decrease with spacing. The 4.9 m row spacing was minimally acceptable for herbage yield and quality. System design should seek to balance tree-crop yield and quality within the context of management constraints and site productivity.