Analysis of N-Species (NO3-, NO2-, and NH4+) in Canadian Marginal Land Soils for Growing Sorghum Biomas

Candidate: Nicole Rodriguez

Supervisor: Dr. Julia Lu

Abstract:
As part of a project to develop low-cost and high production systems for growing sorghum biomass on marginal lands in Canada, this research focuses on analysis of inorganic nitrogen species (NO3-, NO2-, and NH4+) in soil samples collected from 3 selected fields in Ontario. Soil samples were extracted using synthetic rainwater and analyzed using colorimetric methods. Evaluation of NO3- established comparable levels of plant-available N between marginal and agricultural soil, prior to sorghum planting. Comparison of soil from plots of 3 different sorghum hybrids showed no significant influence from hybrid on soil NO3-. Application of N fertilizer influenced soil NO3- levels, but the response differed between marginal sites, as well as in comparison to the agricultural field. At both marginal sites, N fertilizer at the applied rate of 45 kg N ha-1, had no significant impact on sorghum biomass, yet appears sustainable in terms of maintaining available N levels.