Phosphorous Leaching and Depth Stratification in the Biochar Amended Field Soils.

Previous soil column studies have shown clear evidence of the ability of hardwood biochar to retain nutrients (specifically P) in the upper layer of soil columns and significantly reduce P leaching. The objective of this study was to determine biochar impacts on depth stratification of P in field soils and P leaching under field conditions.   Eighteen small field plots (23.7 m²) were established on a glacial-till derived soils by incorporating 0 to 96 Mg ha^-1 of hardwood biochar to a depth of 30 cm in the fall of 2010.  The field was managed as continuous no-till corn. Suction lysimeters were installed in the summer of 2014 at two depths; 15 and 45 cm– within and below the biochar layer. Water samples were collected following rain events during 2015 growing season and analyzed for P and other nutrients by ICP. Soil samples were collected at three depth (0-5, 5-15, and 15-30cm) in the fall of 2014 and analyzed for Mehlich III extractable P and other nutrients. Results of the study will be presented.