Parr, S., G.P. Robertson, A.T. Corbin
Presented at the ASM at Estes Park (2006-09-01 to 2012-09-23 )
With the growing awareness of the environmental impact of humans, land managers are increasingly trying to reduce degradation while maintaining profitability. We tested the impact of management intensity on the level of nitrogen loss through nitrate leaching, greenhouse gas production, and carbon sequestration. Gas, soil water, and soil from four annual cropping systems (corn-soybean-wheat rotations managed as conventional, no-till, low-input, and organic systems), two perennial cropping systems (alfalfa and poplar trees), two successional systems (early and mid-successional old fields), and two forest systems (planted conifer and native deciduous systems) all replicated on the same soil series. Quartz soil water samplers were used to sample leachate, and samples were collected twice a month from March 1995-November 2005, and analyzed for inorganic nitrogen. Nitrate leaching was highest in annual agricultural plots and perennial alfalfa plots. Successional plots and plots with trees (fast growing poplar clones) showed the lowest leaching levels, while native forested sites showed intermediate levels of nitrate loss. Within agricultural systems, conventional tilled and no-tilled systems showed higher leaching losses than organic systems. Carbon sequestration was estimated based on comparisons of initial soil C levels and soil C levels after ten years. Carbon sequestration was highest in successional and perennial systems, although the no-till system also had a high rate of carbon sequestration. Greenhouse gas production was measured using the static chamber method, with samples being taken weekly to monthly from March-December. Greenhouse gas production was similar across all the annual cropping systems and alfalfa, while native systems were consistently lower in greenhouse gas emissions. Results suggest ecosystem service trade-offs in these systems, and that managers will need to make prioritized management choices. Results also show how land use changes alter the partitioning of ecosystem services across the landscape.
Back to meeting | Show |