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Available nitrogen from biochar and manure soil amendments


Background: Nitrogen pollution has become a severe problem in the Chesapeake Bay watershed where there is highly concentrated chicken production. The application of chicken manure and other fertilizers to fields increases the emission of N2O and other greenhouse gases from the soil. Applying biochar made from poultry litter in place of raw poultry litter appears to reduce these gas emissions and increase crop yields. How much inorganic nitrogen (NO3 and NH4) does biochar make available to plants? Methods: We conducted a soil incubation study to analyze the inorganic nitrogen released by different soil amendments over time. Sixty jars were filled with soil from two field sites: one in Delaware and one in Pennsylvania. Jars of soil were assigned one of five treatments, each with six replications: control (no treatment), manure, biochar, urea, or biochar and urea. Each soil amendment was applied at a rate of 0.2 g dry N per jar, corresponding to 320 kg dry N per ha in the field. Subsamples of soil were taken every 3-6 days. NO3 and NH4 were extracted with 2M KCl and analyzed using a colorimetric nutrient analyzer. N2O, NOx, and CO2 fluxes were also measured. Results: Initial results suggest that biochar releases less NH4 than manure or urea. When biochar and urea were combined, NH4 concentrations were lower than for urea alone. N2O emissions appear to be initially higher in biochar treated soils than soils incubated with other fertilizers. Preliminary conclusions: Biochar may interact with urea to reduce the amount of NH4 released. Although biochar reduced emissions (relative to other fertilizers) in a field site with growing corn, it may increase emissions in isolated soils.


Clark, Mahalia, "Available nitrogen from biochar and manure soil amendments" (2014). Summer Research Symposium. Brown Digital Repository. Brown University Library.



  • Summer Research Symposium

    Each year, Brown University showcases the research of its undergraduates at the Summer Research Symposium. More than half of the student-researchers are UTRA recipients, while others receive funding from a variety of Brown-administered and national programs and fellowships and go …