Moisture-driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co-application in tropical soils
Biochar and nitrification inhibitors (NIs) are crucial in improving soil nitrogen (N) availability and decreasing its environmental consequences in agroecosystems. Soil microbes can regulate soil N dynamics through metabolic processes, such as the secretion of extracellular enzymes, which affect bot...
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Elsevier
2025-08-01
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| author | Lijun Liu Qilin Zhu Xiaoqian Dan Huanyu Bao Tongbin Zhu Lei Meng Ahmed S. Elrys Christoph Müller Jinbo Zhang |
| author_facet | Lijun Liu Qilin Zhu Xiaoqian Dan Huanyu Bao Tongbin Zhu Lei Meng Ahmed S. Elrys Christoph Müller Jinbo Zhang |
| author_sort | Lijun Liu |
| collection | DOAJ |
| description | Biochar and nitrification inhibitors (NIs) are crucial in improving soil nitrogen (N) availability and decreasing its environmental consequences in agroecosystems. Soil microbes can regulate soil N dynamics through metabolic processes, such as the secretion of extracellular enzymes, which affect both N production and turnover. However, how and why soil microbial N limitation (MNL) responds to biochar-NIs co-application is poorly understood, especially in tropical regions under different moisture contents. Here, an incubation study was conducted on soils from a long-term rice-vegetable rotation to investigate the effects of five treatments including control (no biochar or NIs), 2 % biochar, 2 % biochar plus 5 % dicyandiamide (DCD), 2 % biochar plus 1 % 3,4 dimethylpyrazole phosphate (DMPP), and 2 % biochar plus 2.5 % DCD and 0.5 % DMPP, at 60 % and 100 % water holding capacity (WHC) on MNL and N availability. Biochar derived from rice straw was applied at a rate of 40 Mg ha−1. All treatments, including the control, received 150 mg N kg−1 as urea, with NIs added proportionally to the applied N mass. The vector-threshold element ratio was applied to evaluate MNL, while δ15N and net N transformation rates were measured to evaluate N availability. The vector-threshold model results indicated severe MNL in studied soils, and that biochar, alone or with NIs, increased δ15N and alleviated the MNL under unsaturated conditions, while the opposite was observed under saturated conditions. Biochar increased the particulate and dissolved organic carbon contents, which in turn increased the net N mineralization rate, thereby alleviating MNL under unsaturated conditions. Relative to biochar, biochar-NIs co-application increased net N mineralization rate under unsaturated conditions. The lower nitrate production in response to biochar, alone or with NIs, decreased δ15N and aggravated MNL under saturated conditions. Among all NIs treatments, biochar + DMPP showed the highest net N mineralization rate, but the lowest MNL at 60 % WHC and the highest MNL at 100 % WHC. Nitrous oxide emissions increased in response to biochar alone, but decreased under biochar-NIs co-application in unsaturated and saturated soils, with the lowest emissions observed for biochar + DCD at 60 % WHC and biochar + DCD + DMPP at 100 % WHC. Our results indicated that soil moisture conditions control the response of MNL and N losses to biochar and NIs in the tropics. |
| format | Article |
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| institution | DOAJ |
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| publishDate | 2025-08-01 |
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| spelling | doaj-art-9d7e56a06d4345ad9eb2ec7d0e2ede652025-08-20T03:23:34ZengElsevierGeoderma1872-62592025-08-0146011745510.1016/j.geoderma.2025.117455Moisture-driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co-application in tropical soilsLijun Liu0Qilin Zhu1Xiaoqian Dan2Huanyu Bao3Tongbin Zhu4Lei Meng5Ahmed S. Elrys6Christoph Müller7Jinbo Zhang8Institute of Karst Geology, CAGS/Key Laboratory of Karst Dynamics, MNR & GZAR/International Research Center on Karst Under the Auspices of UNESCO, Guilin, Guangxi 541004, China; School of Tropical Agriculture and Forest, Hainan University, Haikou 570228, China; Pingguo Guangxi, Karst Ecosystem, National Observation and Research Station, Pingguo, Guangxi 531406, ChinaSchool of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, ChinaSchool of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, ChinaSchool of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, ChinaInstitute of Karst Geology, CAGS/Key Laboratory of Karst Dynamics, MNR & GZAR/International Research Center on Karst Under the Auspices of UNESCO, Guilin, Guangxi 541004, China; Pingguo Guangxi, Karst Ecosystem, National Observation and Research Station, Pingguo, Guangxi 531406, ChinaSchool of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, ChinaSchool of Tropical Agriculture and Forest, Hainan University, Haikou 570228, China; School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; Soil Science Department, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt; Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Giessen 35392, Germany; Corresponding author at: School of Tropical Agriculture and Forest, Hainan University, Haikou 570228, China.Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Giessen 35392, Germany; Institute of Plant Ecology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany; School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin, IrelandSchool of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572025, China; Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Giessen 35392, GermanyBiochar and nitrification inhibitors (NIs) are crucial in improving soil nitrogen (N) availability and decreasing its environmental consequences in agroecosystems. Soil microbes can regulate soil N dynamics through metabolic processes, such as the secretion of extracellular enzymes, which affect both N production and turnover. However, how and why soil microbial N limitation (MNL) responds to biochar-NIs co-application is poorly understood, especially in tropical regions under different moisture contents. Here, an incubation study was conducted on soils from a long-term rice-vegetable rotation to investigate the effects of five treatments including control (no biochar or NIs), 2 % biochar, 2 % biochar plus 5 % dicyandiamide (DCD), 2 % biochar plus 1 % 3,4 dimethylpyrazole phosphate (DMPP), and 2 % biochar plus 2.5 % DCD and 0.5 % DMPP, at 60 % and 100 % water holding capacity (WHC) on MNL and N availability. Biochar derived from rice straw was applied at a rate of 40 Mg ha−1. All treatments, including the control, received 150 mg N kg−1 as urea, with NIs added proportionally to the applied N mass. The vector-threshold element ratio was applied to evaluate MNL, while δ15N and net N transformation rates were measured to evaluate N availability. The vector-threshold model results indicated severe MNL in studied soils, and that biochar, alone or with NIs, increased δ15N and alleviated the MNL under unsaturated conditions, while the opposite was observed under saturated conditions. Biochar increased the particulate and dissolved organic carbon contents, which in turn increased the net N mineralization rate, thereby alleviating MNL under unsaturated conditions. Relative to biochar, biochar-NIs co-application increased net N mineralization rate under unsaturated conditions. The lower nitrate production in response to biochar, alone or with NIs, decreased δ15N and aggravated MNL under saturated conditions. Among all NIs treatments, biochar + DMPP showed the highest net N mineralization rate, but the lowest MNL at 60 % WHC and the highest MNL at 100 % WHC. Nitrous oxide emissions increased in response to biochar alone, but decreased under biochar-NIs co-application in unsaturated and saturated soils, with the lowest emissions observed for biochar + DCD at 60 % WHC and biochar + DCD + DMPP at 100 % WHC. Our results indicated that soil moisture conditions control the response of MNL and N losses to biochar and NIs in the tropics.http://www.sciencedirect.com/science/article/pii/S0016706125002964BiocharExtracellular enzyme stoichiometryNet N transformation rateMicrobial N limitationNitrification inhibitor |
| spellingShingle | Lijun Liu Qilin Zhu Xiaoqian Dan Huanyu Bao Tongbin Zhu Lei Meng Ahmed S. Elrys Christoph Müller Jinbo Zhang Moisture-driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co-application in tropical soils Geoderma Biochar Extracellular enzyme stoichiometry Net N transformation rate Microbial N limitation Nitrification inhibitor |
| title | Moisture-driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co-application in tropical soils |
| title_full | Moisture-driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co-application in tropical soils |
| title_fullStr | Moisture-driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co-application in tropical soils |
| title_full_unstemmed | Moisture-driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co-application in tropical soils |
| title_short | Moisture-driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co-application in tropical soils |
| title_sort | moisture driven shifts in microbial nitrogen limitation under biochar and nitrification inhibitors co application in tropical soils |
| topic | Biochar Extracellular enzyme stoichiometry Net N transformation rate Microbial N limitation Nitrification inhibitor |
| url | http://www.sciencedirect.com/science/article/pii/S0016706125002964 |
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