Tying Together Biochar Properties with Corn Root Development and Nutrient Uptake.

Biochar, the solid coproduct of pyrolysis, has been shown to have variable effects on plant growth based on feedstock material, pyrolysis temperature and duration, crop and soil type. However, to date, the challenge remains in predicting which biochar material which provide consistent, positive results on plant growth.  This project aims to determine if biochar chemical properties (volatile content and composition, fixed C content, ash content, pH, surface area, available N) are a function of feedstock and/or pyrolysis temperature and whether these parameters can be used to predict corn early root development, biomass accumulation and nitrogen uptake.  Nine biochar materials were used: 3 produced from softwood pellets at 500, 550 and 700 C; 2 produced from Miscanthus straw pellets at 550 and 700 C; 2 produced from oil seed rape straw at 550 and 700 C; 2 produced from biosolids at 270 and 320 C.  Corn plants were grown under greenhouse conditions in sandy loam soil, amended with 20 Mg biochar ha-1 until the V3 growth stage (approximately 25 days after seeding).  At harvest roots were washed and scanned using WinRhizo to determine root length, diameter, surface area and volume. Shoot and root biomass was dried, weighed and analyzed for C and N concentrations. Detailed results will be presented, describing the relationship between biochar properties and changes to root morphology, functionality, nutrient uptake and plant biomass accumulation.