Influence of Biochar Addition on the Denitrification Process and N₂O Emission in Cd-Contaminated Soil

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• 作者：Guanhong Chen ; Zhirong Zhang ; Zhiyuan Zhang ; Renduo Zhang
• 关键词：Biochar ; Cd ; contaminated soil ; Denitrification process ; N2O emission
• 刊名：Water, Air, & Soil Pollution
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：228
• 期：1
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment, general; Water Quality/Water Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Soil Science & Conservation; Hydrogeology; Climate Change/Climate Change Impacts;
• 出版者：Springer International Publishing
• ISSN：1573-2932
• 卷排序：228

文摘

The aim of this study was to investigate the effect of biochar addition on the denitrification process and N₂O emission in Cd-contaminated soil. Four different biochars, i.e., dairy manure and rice straw pyrolyzed at 350 and 550 °C, respectively, were added into a Cd-contaminated soil and incubation experiments were conducted for 8 weeks. Results showed that Cd had an inhibitory effect on denitrifying reductase enzymes and reduced the abundance of functional genes. On the contrary, amendment with the biochars increased denitrifying enzyme activity and gene abundance, and thus, enhanced the denitrification process. Labile carbon (C) in the biochar-amended soil, which was calculated based on the two-pool exponential model, was the key factor to facilitate this process. As a less important factor, elevated soil pH by biochar addition also increased denitrifying activity as well as the nosZ abundance. Decrease of Cd bioavailability by the biochar addition was beneficial to the denitrification process. Addition of the biochars with higher amount of NO₃−-N, especially the rice straw-derived biochars, increased cumulative N₂O emission by more than ten times relative to the Cd-contaminated soil. With the great amount of labile C and NO₃−-N, the treatment of biochars prepared at 350 °C released the larger amount of CO₂ and N₂O than other treatments. The biochar addition could totally release the heavy metal stress and restore the Cd-contaminated soil in terms of bacterial community.