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An assessment of phosphorus-enriched poplar biochar as a soil amendment for agriculture

University of British Columbia

Globally, there is an increasing need to develop renewable sources of biomass to alleviate petroleum-derived commodity reliance. In order to do this sustainably and economically, biomass needs to be multi-purpose, and one such product stream is the generation of biochar while employing lignocellulosic biomass for biofuel production. Biochar can be used as a soil amendment to improve soil health, however, the inherent variability in feedstock quality, processing methods, and the variety of feedstocks, impacts biochar utility. Phosphorus is a non-renewable plant macronutrient that is often added in excess to agricultural crops to maximize yield, but is highly susceptible to leaching resulting in contamination of downstream ecosystems. This study examines the phosphorus storage capacity of Populus sp. for bioremediation of phosphorus-rich soils and production of biochar intended for agricultural amendments. Two greenhouse experiments were conducted to study phosphorus uptake and yield of Brassica napus L. using biochar as a growth-media amendment. The first involved the application of mixed-Salicaceae biochar alongside the phosphorus-solubilizing fungus, Penicillium bilaiae. The second experiment involved biochars produced from the poplar genotypes Walker, Tristis and MIN-13, grown in phosphorous-enriched media by slow-pyrolysis at 550°C. B. napus showed increased leaf phosphate content with biochar applications greater than 1.5% w/w with the P. bilaiae, however, its role is questionable, as it may have acted as a competitor for other plant nutrients resulting in decreased overall yield. In the second trial, Walker produced the greatest amount of feedstock, as well as the biochar with highest phosphate concentrations. Moreover, biochar generated from Walker grown on prairie phosphorus levels produced canola with the greatest number of seeds. However, overall, the MIN-13 biochar amendments resulted in greater yields. Nitrogen and micronutrient concentrations may be a better indicator of nutritional value of biochar amendments, compared to phosphorus. Biochar did not affect concentrations of oil or proteins. These results lead to recommendations for future biochar studies and identify important feedstock considerations that need to be addressed.

Text

2019-08-15

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/71303

Forestry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/