Biochar suppressed the decomposition of organic carbon in a cultivated sandy loam soil: a negative priming effect
Date
2014
Authors
Lu, W.
Ding, W.
Zhang, J.
Li, Y.
Luo, J.
Bolan, N.
Xie, Z.
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Journal article
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Soil Biology and Biochemistry, 2014; 76:12-21
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Abstract
Conversion of plant residues to biochar is an attractive strategy for mitigation of atmospheric carbon dioxide (CO₂) emission and enhancement of carbon (C) storage in soil. However, the effect of biochar application on the decomposition of soil organic C (SOC) as well as its mechanisms is not well understood in the sandy loam soil of North China Plain. We investigated how biochar affected the decomposition of native SOC, using stable δ¹³C isotope analyses by applying biochar produced from corn straw (a C₄ plant,δ¹³C ¼ =-11.9⁰/₀₀) to a sandy loam soil (δ¹³C of SOC ¼=-24.5⁰/₀₀) under a long-term C₃ crop rotation. The incubation experiment included four treatments: no amendment (Control), biochar amendment (BC,0.5% of soil mass), inorganic nitrogen (N) amendment (IN, 100 mg N kg⁻¹) and combined biochar and N amendments (BN). Compared with Control, N amendment significantly (P < 0.05) increased total soil CO₂ emission, even when combined with biochar amendment. In contrast, biochar alone amendment did not affect total soil CO₂ emission significantly. However biochar, even when combined with N amendment,significantly (P < 0.05) reduced CO₂ emission from native SOC by 64.9-68.8%, indicating that biochar inhibited the decomposition of native SOC and the stimulation effect of inorganic N on native SOC degradation, a negative priming effect. N addition immediately stimulated the growth of microorganisms and altered microbial community structure by increasing Gram-positive bacteria compared to Control as measured by phospholipid fatty acid. Biochar amendment did not alter microbial biomass during the720-h incubation period except at 168 and 720 h, but significantly (P < 0.05) lowered dissolved organic C(DOC) content in soil, primarily due to sorption of DOC by the biochar. Our study suggested that biochar application could effectively reduce the decomposition of native organic C and a potential effective measure for C sequestration in the test soil of the North China Plain.incubation experiment included four treatments: no amendment (Control), biochar amendment (BC,0.5% of soil mass), inorganic nitrogen (N) amendment (IN, 100 mg N kg⁻¹) and combined biochar and N amendments (BN). Compared with Control, N amendment significantly (P < 0.05) increased total soil CO2emission, even when combined with biochar amendment. In contrast, biochar alone amendment did not affect total soil CO2 emission significantly. However biochar, even when combined with N amendment,significantly (P < 0.05) reduced CO2 emission from native SOC by 64.9e68.8%, indicating that biochar inhibited the decomposition of native SOC and the stimulation effect of inorganic N on native SOC degradation, a negative priming effect. N addition immediately stimulated the growth of microorganisms and altered microbial community structure by increasing Gram-positive bacteria compared to Control as measured by phospholipid fatty acid. Biochar amendment did not alter microbial biomass during the720-h incubation period except at 168 and 720 h, but significantly (P < 0.05) lowered dissolved organic C (DOC) content in soil, primarily due to sorption of DOC by the biochar. Our study suggested that biochar application could effectively reduce the decomposition of native organic C and a potential effective measure for C sequestration in the test soil of the North China Plain.
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Copyright 2014 Elsevier