Biochar Application Increases Labile Carbon and Inorganic Nitrogen Supply in a Continuous Monocropping Soil

Rong Huang, Bing Li, Yulan Chen, Qi Tao, Qiang Xu, Denghong Wen, Xuesong Gao, Qiquan Li, Xiaoyan Tang and Changquan Wang
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Rong Huang: College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Bing Li: College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Yulan Chen: Liangshan Branch of Sichuan Tobacco Corporation, Xichang 615000, China
Qi Tao: College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Qiang Xu: College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Denghong Wen: College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Xuesong Gao: College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Qiquan Li: College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Xiaoyan Tang: College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Changquan Wang: College of Resources, Sichuan Agricultural University, Chengdu 611130, China

Land, 2022, vol. 11, issue 4, 1-17

Abstract: Biochar is an effective method for increasing soil carbon (C) sequestration and nitrogen (N) supply under continuous monocropping. To investigate the impact of biochar placement methods on soil C and N, a one-year field experiment with five treatments was conducted including control, mineral fertilizers only (F), biochar hole placement (BFH; biochar applied to the soil layer at 5–10 cm) + F, biochar band placement (BFB; biochar applied to the soil layer at 15–20 cm) + F, and biochar band and hole placement + F (BFBH). The results showed that, regardless of the placement method, biochar application increased soil total organic C (TOC) and C pool management index by 6.9–39.7% and 4.1–36.1%, respectively, especially for dissolved organic C (DOC; 6.9–51.3%), readily oxidizable C (ROC; 2.4–46.4%), and microbial biomass C (MBC; 10.4–41.7%). Single biochar placement methods significantly influenced DOC, MBC, and ROC contents of both soil layers in the rank order of BFH ≈ BFBH > BFB at 0–15 cm and BFB ≈ BFBH > BFH at 15–30 cm. Soil TN and microbial biomass N (MBN) mainly accumulated at the site of biochar placement. The increased soil TOC:TN and MBC:N ratios under biochar treatments promoted inorganic N immobilization and reduced the loss of ammonium N and nitrate N (NO 3 − -N) through leaching at the early stage of tobacco growth. Biochar-adsorbed N was remobilized at a later period (vigorous growth stage and maturity), possibly causing the slow decrease in NO 3 − -N content. Additionally, soil C and N pools were significantly influenced by the main effects of soil layer and growth stage. Overall, biochar application increased soil C and N pools and inorganic N supply through N remobilization. However, the increased labile organic C content and microbial activity may prevent C sequestration in biochar-amended soils.

Keywords: biochar; soil labile organic C; soil inorganic N; placement method (search for similar items in EconPapers)
JEL-codes: Q15 Q2 Q24 Q28 Q5 R14 R52 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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