Biochar applications to boreal podzol improve soil hydraulic properties and control nitrogen dynamics

• Published in: Canadian Journal of Soil Science
• Main Authors: Saha, Ratnajit, Thomas, Raymond, Hawboldt, Kelly, Nadeem, Muhammad, Cheema, Mumtaz, Galagedara, Lakshman
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2023
• Subjects: Soil Science; Canada; Newfoundland
• Online Access: http://dx.doi.org/10.1139/cjss-2022-0086; https://cdnsciencepub.com/doi/full-xml/10.1139/cjss-2022-0086; https://cdnsciencepub.com/doi/pdf/10.1139/cjss-2022-0086

The study aimed to investigate the effects of biochar (BC) application on hydraulic properties and nitrogen (N) transport in a podzolic soil profile. Soil samples were collected from an agricultural research field in Pasadena, Newfoundland, Canada. The following three types of leaching columns were prepared: ( i) topsoil, ( ii) top and E-horizon soil, and ( iii) mixed soil (2:1 ratio of topsoil and E-horizon soil). Granular biochar (GBC) and powder biochar (PBC) were mixed with soils at the rate of 0%, 1% and 2% (w/w). BC’s morphological structure and pore size distribution were examined using a scanning electron microscope, and the specific surface area was assessed by the Brunauer−Emmett−Teller method. Soil physical and hydraulic properties (bulk density, porosity, field capacity (FC), permanent wilting point, plant available water (PAW)), leaching concentration of nitrate (NO 3 − ) and ammonium (NH 4 + ), and volume of leachate were measured through a total of 378 experiments under laboratory conditions. GBC and PBC showed hydrophobic and hydrophilic characteristics, respectively. With the 2% PBC amendment, porosity increased by 3%, FC by 10%, and PAW by 13% in the mixed soil and reduced NO 3 − leaching by 36% in top and E-horizon soil and NH 4 + leaching by 72% in mixed soil. On the other hand, NO 3 − and NH 4 + leaching was reduced by 26% and 33% in mixed soil when treated with 2% GBC. A 2% application rate for both BC (GBC and PBC) showed the best performance to enhance soil hydraulic properties and retain significant amounts of NO 3 − and NH 4 + in the boreal podzol.