Soil nitrogen dynamics in switchgrass seeded to a marginal cropland in South Dakota

• Published in: Global change biology. Bioenergy Vol. 10; no. 1; pp. 28 - 38
• Main Authors: Lai, Liming, Oh Hong, Chang, Kumar, Sandeep, Osborne, Shannon L., Lehman, R. Michael, Owens, Vance N.
• Format: Journal Article
• Language: English
• Published: Oxford John Wiley & Sons, Inc 01-01-2018
• Subjects: Agricultural land; Biofuels; Biomass; Dynamics; Emissions; Energy crops; Environmental conditions; Environmental impact; Fertilization; Fluxes; Land management; Landscape; landscape position; Leaching; nitrate (NO3−) leaching; Nitrates; Nitrogen; nitrogen (N) dynamics; nitrogen (N) fertilization rate; Nitrous oxide; nitrous oxide (N2O); Panicum virgatum; Soil dynamics; soil nitrate (NO3−); Soils; switchgrass (Panicum virgatum L.)
• ISSN: 1757-1693; 1757-1707
• DOI: 10.1111/gcbb.12475

The potential ecological impacts of switchgrass (Panicum virgatum L.), as a biofuel feedstock, have been assessed under different environmental conditions. However, limited information is available in understanding the integrated analysis of nitrogen (N) dynamics including soil nitrate (NO3−), nitrous oxide (N2O) emissions, and NO3− leaching under switchgrass land management. The specific objective was to explore N dynamics for 2009 through 2015 in switchgrass seeded to a marginally yielding cropland based on treatments of N fertilization rate (N rate; low, 0; medium, 56; high, 112 kg N ha−1) and landscape position (shoulder, backslope, and footslope). Our findings indicated that N rate impacted soil NO3− (0–5 cm depth) and surface N2O fluxes but did not impact NO3− leaching during the observed years. Medium N (56 kg N ha−1) was the optimal rate for increasing biomass yield with reduced environmental problems. Landscape position impacted the N dynamics. At the footslope position, soil NO3−, soil NO3− leaching, and N2O fluxes were higher than the other landscape positions. Soil N2O fluxes and NO3− leaching had downward trends over the observed years. Growing switchgrass on marginally yielding croplands can store soil N, reduce N losses via leaching, and mitigate N2O emissions from soils to the atmosphere over the years. Switchgrass seeded on marginally yielding croplands can be beneficial in reducing N losses and can be grown as a sustainable bioenergy crop on these marginal lands.