Assessing GHG Contributions in Crop-Cattle-Conifer Connections of Alley Cropping/Silvopasture Systems.

U.S. agricultural lands are being targeted to increase food/feed/fiber/biofuel production, along with other economic and environmental services - without increasing GHG emissions. At the same time, capacity to meet these many objectives under potential climate change (CC) is being questioned. Agroforestry, one of the CC production-conservation strategies being considered for agricultural lands, has potential to contribute to both GHG mitigation and CC adaptation.  However, we currently lack research and data to estimate these contributions; limiting our ability to account for and capitalize on them through improved management strategies. Alley cropping, the intentional integration of trees and crops, and silvopasture, the intentional integration of trees, forage and livestock, can potentially create productive and profitable operations by mitigating risks involved with changing climate and fluctuating markets.  GHG fluxes in these systems encompass the potentially favorable process of carbon sequestration in woody and possibly soil components, and reduced N₂O emission through decreased application of fertilizers and tightened nutrient cycling in more stratified and diverse systems, as well as potential reduction in CH₄ production if high forage quality can be managed with rotational grazing schemes.  We intend to characterize GHG fluxes (N₂O, CH₄ and C sequestration) in a 17-acre agroforestry research and extension alley cropping/silvopasture trial (randomized block design: five replications, 3 tree species and 2 alley widths) established at the Center for Environmental Farming Systems in Goldsboro, North Carolina.   Initial focus will be on developing suitable monitoring/measurement approaches utilizing GRACEnet protocols. Ultimately, the measurement/estimation approach will need to account for the net GHG impact from the wide variety of management activities used in these systems (e.g. fertilization, liming, mowing, and species for the forage component to frequency, intensity and timing of grazing rotations to thinning, pruning and species management of the woody component).