Location: Integrated Cropping Systems ResearchTitle: Soil nitrogen dynamics in switchgrass seeded to a marginally yielding cropland of South Dakota Author
Submitted to: Global Change Biology Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/2/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: Using marginal croplands to raise switchgrass for biofuel production may result in economic and environmental benefits. To consistently produce sufficient switchgrass biomass, N fertilizer may have to be applied. The amount of applied N will be critical in determining the economic and environmental benefits from switchgrass production systems. We found that a moderate rate of N (56 kg N ha-1) application was optimum for producing switchgrass biomass without loss of N via leaching or nitrous oxide emission to the environment. Lower landscape positions (e.g., footslope) were found to increase loss of N to the environment. These findings provide guidance for efficient production of switchgrass biomass.
Technical Abstract: Soil nitrate (NO3-), nitrate leaching, and nitrous oxide (N2O) emissions for 2009 through 2015 were monitored to explore N dynamics in switchgrass (Panicum virgatum L.) seeded to a marginally yielding cropland. Our findings indicated that N rate impacted soil NO3- (0-5 cm depth) and soil surface N2O fluxes but did not impact NO3- leaching after five years of continuous growing switchgrass. Medium N (56 kg N ha-1) was turned out to the optimal rate for increasing the biomass yield with reduced environmental problems. Landscape position impacted the N dynamics. At footslope position, there was higher soil NO3-, NO3- leaching and N2O fluxes than the other positions. Data from this study showed that growing switchgrass on marginally yielding croplands can store N nutrient, reduce N losses via leaching, and mitigate N2O emissions from soils to the atmosphere over time.