title: Biochar for the mitigation of nitrate leaching from soil amended with biosolids.
abstract: Countries with sewage treatment plants produce on average 27 kg of dried biosolids/person/yr. Concerns about nitrate leaching limit the rate at which biosolids are added to soil. We sought to determine whether biochar, a form of charcoal that is added to soil, could reduce nitrate leaching from biosolids amended soil. We set up 24 (0.5 m × 0.75 m) lysimeters, filled with two soil types (Templeton Silt Loam and Ashley Dene silt loam) and amended with combinations of biochar (102 t/ha equivalent) and biosolids (600 and 1200 kg N/ha equivalent). Pasture and leachates were sampled over 5 months. Nitrate leaching from biochar plus biosolids amended soils were reduced to levels at or below the control treatments. Pasture N concentrations were similarly affected by biochar addition. Future research should focus on unravelling the mechanism responsible for the change in the nitrogen cycle in soils amended with biosolids and biochar.
authors.affiliation: Soil and Physical Sciences Department, Faculty of Agricultural and Life Sciences, Lincoln University, PO Box 7647, Lincoln 7647, New Zealand.
authors.forename: O A
authors.initials: OA
authors.lastname: Knowles
authors.forename: B H
authors.initials: BH
authors.lastname: Robinson
authors.forename: A
authors.initials: A
authors.lastname: Contangelo
authors.forename: L
authors.initials: L
authors.lastname: Clucas
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D009566:Nitrates / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D058458:Nitrogen Cycle; D010944:Plants / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D014865:Waste Disposal, Fluid
chemical_list: D009566:Nitrates; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal