Cargando…
Nitrogen turnover and N(2)O/N(2) ratio of three contrasting tropical soils amended with biochar
Biochar has been reported to reduce emission of nitrous oxide (N(2)O) from soils, but the mechanisms responsible remain fragmentary. For example, it is unclear how biochar effects on N(2)O emissions are mediated through biochar effects on soil gross N turnover rates. Hence, we conducted an incubatio...
Autores principales: | , , , , , , , , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Elsevier Scientific Pub. Co
2019
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6559130/ https://www.ncbi.nlm.nih.gov/pubmed/31423022 http://dx.doi.org/10.1016/j.geoderma.2019.04.007 |
_version_ | 1783425775378104320 |
---|---|
author | Fungo, Bernard Chen, Zhe Butterbach-Bahl, Klaus Lehmannn, Johannes Saiz, Gustavo Braojos, Víctor Kolar, Allison Rittl, Tatjana F. Tenywa, Moses Kalbitz, Karsten Neufeldt, Henry Dannenmann, Michael |
author_facet | Fungo, Bernard Chen, Zhe Butterbach-Bahl, Klaus Lehmannn, Johannes Saiz, Gustavo Braojos, Víctor Kolar, Allison Rittl, Tatjana F. Tenywa, Moses Kalbitz, Karsten Neufeldt, Henry Dannenmann, Michael |
author_sort | Fungo, Bernard |
collection | PubMed |
description | Biochar has been reported to reduce emission of nitrous oxide (N(2)O) from soils, but the mechanisms responsible remain fragmentary. For example, it is unclear how biochar effects on N(2)O emissions are mediated through biochar effects on soil gross N turnover rates. Hence, we conducted an incubation study with three contrasting agricultural soils from Kenya (an Acrisol cultivated for 10-years (Acrisol10); an Acrisol cultivated for over 100-years (Acrisol100); a Ferralsol cultivated for over 100 years (Ferralsol)). The soils were amended with biochar at either 2% or 4% w/w. The (15)N pool dilution technique was used to quantify gross N mineralization and nitrification and microbial consumption of extractable N over a 20-day incubation period at 25 °C and 70% water holding capacity of the soil, accompanied by N(2)O emissions measurements. Direct measurements of N(2) emissions were conducted using the helium gas flow soil core method. N(2)O emissions varied across soils with higher emissions in Acrisols than in Ferralsols. Addition of 2% biochar reduced N(2)O emissions in all soils by 53 to 78% with no significant further reduction induced by addition at 4%. Biochar effects on soil nitrate concentrations were highly variable across soils, ranging from a reduction, no effect and an increase. Biochar addition stimulated gross N mineralization in Acrisol-10 and Acrisol-100 soils at both addition rates with no effect observed for the Ferralsol. In contrast, gross nitrification was stimulated in only one soil but only at a 4% application rate. Also, biochar effects on increased NH(4)(+) immobilization and NO(3)(−)consumption strongly varied across the three investigated soils. The variable and bidirectional biochar effects on gross N turnover in conjunction with the unambiguous and consistent reduction of N(2)O emissions suggested that the inhibiting effect of biochar on soil N(2)O emission seemed to be decoupled from gross microbial N turnover processes. With biochar application, N(2) emissions were about an order of magnitude higher for Acrisol-10 soils compared to Acrisol-100 and Ferralsol-100 soils. Our N(2)O and N(2) flux data thus support an explanation of direct promotion of gross N(2)O reduction by biochar rather than effects on soil extractable N dynamics. Effects of biochar on soil extractable N and gross N turnover, however, might be highly variable across different soils as found here for three typical agricultural soils of Kenya. |
format | Online Article Text |
id | pubmed-6559130 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Elsevier Scientific Pub. Co |
record_format | MEDLINE/PubMed |
spelling | pubmed-65591302019-08-15 Nitrogen turnover and N(2)O/N(2) ratio of three contrasting tropical soils amended with biochar Fungo, Bernard Chen, Zhe Butterbach-Bahl, Klaus Lehmannn, Johannes Saiz, Gustavo Braojos, Víctor Kolar, Allison Rittl, Tatjana F. Tenywa, Moses Kalbitz, Karsten Neufeldt, Henry Dannenmann, Michael Geoderma Article Biochar has been reported to reduce emission of nitrous oxide (N(2)O) from soils, but the mechanisms responsible remain fragmentary. For example, it is unclear how biochar effects on N(2)O emissions are mediated through biochar effects on soil gross N turnover rates. Hence, we conducted an incubation study with three contrasting agricultural soils from Kenya (an Acrisol cultivated for 10-years (Acrisol10); an Acrisol cultivated for over 100-years (Acrisol100); a Ferralsol cultivated for over 100 years (Ferralsol)). The soils were amended with biochar at either 2% or 4% w/w. The (15)N pool dilution technique was used to quantify gross N mineralization and nitrification and microbial consumption of extractable N over a 20-day incubation period at 25 °C and 70% water holding capacity of the soil, accompanied by N(2)O emissions measurements. Direct measurements of N(2) emissions were conducted using the helium gas flow soil core method. N(2)O emissions varied across soils with higher emissions in Acrisols than in Ferralsols. Addition of 2% biochar reduced N(2)O emissions in all soils by 53 to 78% with no significant further reduction induced by addition at 4%. Biochar effects on soil nitrate concentrations were highly variable across soils, ranging from a reduction, no effect and an increase. Biochar addition stimulated gross N mineralization in Acrisol-10 and Acrisol-100 soils at both addition rates with no effect observed for the Ferralsol. In contrast, gross nitrification was stimulated in only one soil but only at a 4% application rate. Also, biochar effects on increased NH(4)(+) immobilization and NO(3)(−)consumption strongly varied across the three investigated soils. The variable and bidirectional biochar effects on gross N turnover in conjunction with the unambiguous and consistent reduction of N(2)O emissions suggested that the inhibiting effect of biochar on soil N(2)O emission seemed to be decoupled from gross microbial N turnover processes. With biochar application, N(2) emissions were about an order of magnitude higher for Acrisol-10 soils compared to Acrisol-100 and Ferralsol-100 soils. Our N(2)O and N(2) flux data thus support an explanation of direct promotion of gross N(2)O reduction by biochar rather than effects on soil extractable N dynamics. Effects of biochar on soil extractable N and gross N turnover, however, might be highly variable across different soils as found here for three typical agricultural soils of Kenya. Elsevier Scientific Pub. Co 2019-08-15 /pmc/articles/PMC6559130/ /pubmed/31423022 http://dx.doi.org/10.1016/j.geoderma.2019.04.007 Text en © 2019 The Authors http://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Fungo, Bernard Chen, Zhe Butterbach-Bahl, Klaus Lehmannn, Johannes Saiz, Gustavo Braojos, Víctor Kolar, Allison Rittl, Tatjana F. Tenywa, Moses Kalbitz, Karsten Neufeldt, Henry Dannenmann, Michael Nitrogen turnover and N(2)O/N(2) ratio of three contrasting tropical soils amended with biochar |
title | Nitrogen turnover and N(2)O/N(2) ratio of three contrasting tropical soils amended with biochar |
title_full | Nitrogen turnover and N(2)O/N(2) ratio of three contrasting tropical soils amended with biochar |
title_fullStr | Nitrogen turnover and N(2)O/N(2) ratio of three contrasting tropical soils amended with biochar |
title_full_unstemmed | Nitrogen turnover and N(2)O/N(2) ratio of three contrasting tropical soils amended with biochar |
title_short | Nitrogen turnover and N(2)O/N(2) ratio of three contrasting tropical soils amended with biochar |
title_sort | nitrogen turnover and n(2)o/n(2) ratio of three contrasting tropical soils amended with biochar |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6559130/ https://www.ncbi.nlm.nih.gov/pubmed/31423022 http://dx.doi.org/10.1016/j.geoderma.2019.04.007 |
work_keys_str_mv | AT fungobernard nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT chenzhe nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT butterbachbahlklaus nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT lehmannnjohannes nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT saizgustavo nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT braojosvictor nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT kolarallison nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT rittltatjanaf nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT tenywamoses nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT kalbitzkarsten nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT neufeldthenry nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar AT dannenmannmichael nitrogenturnoverandn2on2ratioofthreecontrastingtropicalsoilsamendedwithbiochar |