We investigated the effect of biochar type on plant performance and soil nitrogen (N) transformations in mesocosms representing an organic lettuce (Lactuca sativa) production system. Five biochar materials were added to a silt loam soil: Douglas fir wood pyrolyzed at 410 °C (W410), Douglas fir wood pyrolyzed at 510 °C (W510), pine chip pyrolyzed at 550 °C (PC), hogwaste wood pyrolyzed between 600 and 700 °C (SWC), and walnut shell gasified at 900 °C (WS). Soil pH and cation exchange capacity were significantly increased by WS biochar only. Gross mineralization increased in response to biochar materials with high H/C ratio (i.e., W410, W510, and SWC), which can be favorable for organic farming systems challenged by insufficient N mineralization during plant growth. Net nitrification was increased by W510, PC, and WS without correlating with the abundance of ammonia oxidizing gene (amoA). Increases in N transformation rates did not translate into increases in plant productivity or leaf N content. WS biochar increased the abundance of amoA and nitrite reductase gene (nirK), while SWC biochar decreased the abundance of amoA and nitrous oxide gene (nosZ). Decreases in N 2 O emissions were only observed in soil amended with W510 for 3 days out of the 42-day growing season without affecting total cumulative N 2 O fluxes. This suggests that effects of biochar on decreasing N 2 O emissions may be transient, which compromise biochar’s potential to be used as a N 2 O mitigation strategy in organic systems. Overall, our results confirm that different biochar materials can distinctively affect soil properties and N turnover.
CITATION STYLE
Pereira, E. I. P., Suddick, E. C., Mansour, I., Mukome, F. N. D., Parikh, S. J., Scow, K., & Six, J. (2015). Biochar alters nitrogen transformations but has minimal effects on nitrous oxide emissions in an organically managed lettuce mesocosm. Biology and Fertility of Soils, 51(5), 573–582. https://doi.org/10.1007/s00374-015-1004-5
Mendeley helps you to discover research relevant for your work.