Effect of pristine and Fe-modified rice husk-derived biochar on denitrification and N2O emission in calcareous arable soil.

Autor: Wang, Chaoxu, Chang, Zhilin, Liu, Yongchao, Li, Yuankun, Chen, Qibin, Liu, Guangming
Předmět:
Zdroj: Journal of Soils & Sediments: Protection, Risk Assessment, & Remediation; Jun2023, Vol. 23 Issue 6, p2529-2543, 15p
Abstrakt: Purpose: The objective of the study was to explore the effect of pristine (rice husk-derived biochar produced at 500 ℃ by a Japanese company, JBC) and FeCl3-modified biochar (JBC-Fe) and its application rate on denitrification and N2O emission in calcareous arable soil and the potential mechanisms. Methods: After biochar preparation and characterization, JBC or JBC-Fe was thoroughly mixed with the soil at the mass ratio of 2% or 5%, which were defined as JBC-2%, JBC-5%, JBC-Fe-2%, and JBC-Fe-5%, respectively, and a control treatment without any biochar addition was also arranged. After 7-day preincubation, an 8-day microcosm incubation experiment was carried out consecutively under the condition of facilitating denitrification. N2O and N2O + N2 emission rates were determined, and the distribution pattern of N2O and N2, as the end products of denitrification, was distinguished by the acetylene inhibition method. The dynamic changes of soil physicochemical properties and the activities of nitrate reductase and nitrite reductase during incubation were also explored. Results: Results showed that both JBC and JBC-Fe promoted soil cumulative N2O + N2 and N2O emission during the 8-day incubation. Compared with JBC-2%/JBC-5%, the cumulative N2O + N2 emission of JBC-Fe-2%/JBC-Fe-5% significantly increased by 9.83%/41.21% and the cumulative N2O emission significantly increased by 465.98%/147.68%, respectively (p < 0.05), indicating that JBC-Fe promoted soil NO3 reduction and inhibited N2O reduction compared to JBC. Compared with 2% biochar addition, 5% biochar addition increased soil C/N ratio, decreased the bioavailability of nitrogen and inhibited soil nitrate reductase activity, and subsequently decreased the cumulative N2O + N2 emission. Moreover, 5% biochar addition also inhibited soil N2O reductase activity, resulting in the increase of cumulative N2O emission. Conclusions: JBC-Fe did not show the greenhouse gas mitigation benefits, but increased N2O emission from the calcareous arable soil under the condition of facilitating denitrification (e.g., after heavy rainfall, irrigation, and fertilization). The study provides a theoretical basis to functional biochar production and its engineering application in calcareous arable soil. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index