Nitrogen fractions in the microbial biomass in soils of southern Brazil

Camargo, F. A.O.; Gianello, C.; Vidor, C.

doi:10.1590/S0100-06831999000100022

Abstracts

The reaction of nitrogen compounds with ninhydrin can be used as an indicator of cytoplasmic materials released from microbial cells killed by fumigation. Total-N, ninhydrin-reactive-N (NR-N), ammonium-N (A-N), and α-amino-N in the microbial biomass of soils from the State of Rio Grande do Sul, Brazil, were determined, in 1996, in 0.5 mol L-1 K2SO4 extracts of fumigated and non-fumigated soils. Total-N varied from 20.3 to 104.4 mg kg-1 and the ninhydrin-reactive-N corresponded, in average, to 27% of this. The ninhydrin-reactive-N was made up of 67% ammonium-N and 33% aminoacids with the amino group at the α-carbon position. It was concluded that colorimetric analysis of NR-N and A-N may be used as a direct measure of microbial N in soil. This simple and rapid procedure is adequate for routine analyses.

Biomass-N; biomass ninhydrin-reactive-N; biomass ammonium-N; biomass α-amino-N

A reação de compostos nitrogenados com a ninhidrina pode ser utilizada como parâmetro indicador dos produtos citoplásmicos oriundos da lise de células microbianas mortas pela fumigação. Com base nessa assertiva, realizou-se o presente trabalho, em 1996, com o objetivo de avaliar as concentrações de N-total, N-reativo com ninhidrina (NR-N), N-amônio (A-N) e N-a-amino presentes na biomassa microbiana de solos do Rio Grande do Sul. A partir da extração com K2SO4 0,5 mol L-1 de amostras provenientes de solos fumigados e não fumigados, determinaram-se as frações nitrogenadas presentes na biomassa. Constatou-se que a quantidade do N-total presente na biomassa variou de 20,3 a 104,4 mg kg-1 de solo, sendo a fração microbiana reativa com a ninhidrina correspondente a 27% desses valores, em média. Dois terços dessa fração eram constituídos de nitrogênio na forma de amônio microbiano e um terço na forma de aminoácidos contendo o radical amino no carbono α. É possível utilizar a análise colorimétrica do NR-N e do A-N para a quantificação do N-microbiano do solo. Tais procedimentos são rápidos, simples e aplicáveis em análises de rotina.

biomassa microbiana do N; do N-reativo com ninhidrina; do N-amônio e do N-α--amino

NOTA

Nitrogen fractions in the microbial biomass in soils of southern Brazil

Frações do nitrogênio na microbiota de solos do sul do Brasil

F. A.O. Camargo; C. Gianello; C. Vidor

Professor do Departamento de Solos, Faculdade de Agronomia, Universidade Federal do Rio Grande do Sul. Caixa Postal 776, CEP 90001-970 Porto Alegre (RS). E-mail: labsolos@datacontrol.com.br

ABSTRACT

The reaction of nitrogen compounds with ninhydrin can be used as an indicator of cytoplasmic materials released from microbial cells killed by fumigation. Total-N, ninhydrin-reactive-N (NR-N), ammonium-N (A-N), and α-amino-N in the microbial biomass of soils from the State of Rio Grande do Sul, Brazil, were determined, in 1996, in 0.5 mol L^-1 K₂SO₄ extracts of fumigated and non-fumigated soils. Total-N varied from 20.3 to 104.4 mg kg^-1 and the ninhydrin-reactive-N corresponded, in average, to 27% of this. The ninhydrin-reactive-N was made up of 67% ammonium-N and 33% aminoacids with the amino group at the α-carbon position. It was concluded that colorimetric analysis of NR-N and A-N may be used as a direct measure of microbial N in soil. This simple and rapid procedure is adequate for routine analyses.

Index terms: Biomass-N, biomass ninhydrin-reactive-N, biomass ammonium-N, biomass α-amino-N

RESUMO

A reação de compostos nitrogenados com a ninhidrina pode ser utilizada como parâmetro indicador dos produtos citoplásmicos oriundos da lise de células microbianas mortas pela fumigação. Com base nessa assertiva, realizou-se o presente trabalho, em 1996, com o objetivo de avaliar as concentrações de N-total, N-reativo com ninhidrina (NR-N), N-amônio (A-N) e N-a-amino presentes na biomassa microbiana de solos do Rio Grande do Sul. A partir da extração com K₂SO₄ 0,5 mol L^-1 de amostras provenientes de solos fumigados e não fumigados, determinaram-se as frações nitrogenadas presentes na biomassa. Constatou-se que a quantidade do N-total presente na biomassa variou de 20,3 a 104,4 mg kg^-1 de solo, sendo a fração microbiana reativa com a ninhidrina correspondente a 27% desses valores, em média. Dois terços dessa fração eram constituídos de nitrogênio na forma de amônio microbiano e um terço na forma de aminoácidos contendo o radical amino no carbono α. É possível utilizar a análise colorimétrica do NR-N e do A-N para a quantificação do N-microbiano do solo. Tais procedimentos são rápidos, simples e aplicáveis em análises de rotina.

Termos de Indexação: biomassa microbiana do N, do N-reativo com ninhidrina, do N-amônio e do N-α-amino.

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LITERATURE CITED

Received for publication in January of 1997

Aproved in October of 1998

AMATO, M. & LADD, J.N. An assay for microbial biomass based on ninhydrin-reactive nitrogen in extracts of fumigated soils. Soil Biol. Biochem., 20:107-114, 1988.
ANDERSON, J.P.E. & DOMSCH, K.H. Quantities of plant nutrients in the microbial biomass of selected soils. Soil Biol. Biochem., 130:211-216, 1980.
BADALUCCO, L.; GELSOMINO, A.; DELL'ORCO, S. GRECO, S. & NANNIPIERI, P. Biochemical characterization of soil organic compounds extracted by 0.5 M K₂SO₄ before and after chloroform fumigation. Soil Biol. Biochem., 24:569-578, 1992.
BROOKES, P.C.; LANDMAN, A.; PRUDEN, G. & JENKINSON, D.S. Chloroform fumigation and the release of soil nitrogen: a rapid direct extraction method for measuring microbial biomass nitrogen in soil. Soil Biol. Biochem., 17:837-842, 1985.
CAMARGO, F.A.O.; GIANELLO, C. & VIDOR, C. Tempo de hidrólise e concentração de ácido para fracionamento do nitrogênio orgânico do solo. Pesq. Agropec. Bras., 32:221-227, 1997a.
CAMARGO, F.A.O.; GIANELLO, C. & VIDOR, C. Comparative study of five hydrolytic methods in the determination of soil organic nitrogen compounds. Comm. Soil Sci. Plant Anal., 28:13030-13090, 1997b.
CARTER, M.R. Ninhydrin-reactive N released by the fumigation-extraction method as a measure of microbial biomass under field conditions. Soil Biol. Biochem., 23:139-143, 1991.
DUXBURY, J.M.; SMITH, M.S. & DORAN, J.W. Organic matter as a source and sink of plant nutrients. In: COLEMAN, D.C.; OADES, J.M. & UEHARA, G., eds. Dynamics of soil organic matter in tropical ecosystems. Honululu, University of Hawaii Press, 1989. p.33-68.
INOBUSHI, K.; BROOKES, P.C. & JENKINSON, D.S. Soil microbial biomass C, N, and ninhydrin-N in aerobic and anaerobic soils measured by the fumigation-extraction method. Soil Biol. Biochem., 23:737-741, 1991.
JOERGENSEN, R.G. & BROOKES, P.C. Ninhydrin-reactive nitrogen measurements of microbial biomass in 0.5 M K₂SO₄ soil extracts. Soil Biol. Biochem., 22:1023-1027, 1990.
NHEIDHARDT, F.C.; INGRAHAM, J.L. & SCHAECHTER, M. Biosynthesis and fuelling. In: Physiology of the bacterial cell: a molecular approach. Massachusetts, Sinauer Publishers, 1990. p.133-173.
SPARLING, G.P.; GUPTA, V.V.S.R. & ZHU, C. Release of ninhydrin-reactive compounds during fumigation of soil to estimate microbial C and N. Soil Biol. Biochem., 25:1083-1085, 1993.
TEDESCO, M.J.; GIANELLO, C.; BISSANI, C.; BOHNEN, H. & VOLKWEISS, S.J. Análises de solo, plantas e outros materiais. 2 ed. Porto Alegre, Universidade Federal do Rio Grande do Sul, 1995. 174p. (Boletim Técnico, 5)
VANCE, E.D.; BROOKES, P.C. & JENKINSON, D.S. An extraction method for measuring soil microbial biomass C. Soil Biol. Biochem., 19:697-702, 1987.

Publication Dates

Publication in this collection
07 Oct 2014
Date of issue
Mar 1999

History

Accepted
Oct 1998
Received
Jan 1997

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] AMATO, M. & LADD, J.N. An assay for microbial biomass based on ninhydrin-reactive nitrogen in extracts of fumigated soils. Soil Biol. Biochem., 20:107-114, 1988.

[2] ANDERSON, J.P.E. & DOMSCH, K.H. Quantities of plant nutrients in the microbial biomass of selected soils. Soil Biol. Biochem., 130:211-216, 1980.

[3] BADALUCCO, L.; GELSOMINO, A.; DELL'ORCO, S. GRECO, S. & NANNIPIERI, P. Biochemical characterization of soil organic compounds extracted by 0.5 M K₂SO₄ before and after chloroform fumigation. Soil Biol. Biochem., 24:569-578, 1992.

[4] BROOKES, P.C.; LANDMAN, A.; PRUDEN, G. & JENKINSON, D.S. Chloroform fumigation and the release of soil nitrogen: a rapid direct extraction method for measuring microbial biomass nitrogen in soil. Soil Biol. Biochem., 17:837-842, 1985.

[5] CAMARGO, F.A.O.; GIANELLO, C. & VIDOR, C. Tempo de hidrólise e concentração de ácido para fracionamento do nitrogênio orgânico do solo. Pesq. Agropec. Bras., 32:221-227, 1997a.

[6] CAMARGO, F.A.O.; GIANELLO, C. & VIDOR, C. Comparative study of five hydrolytic methods in the determination of soil organic nitrogen compounds. Comm. Soil Sci. Plant Anal., 28:13030-13090, 1997b.

[7] CARTER, M.R. Ninhydrin-reactive N released by the fumigation-extraction method as a measure of microbial biomass under field conditions. Soil Biol. Biochem., 23:139-143, 1991.

[8] DUXBURY, J.M.; SMITH, M.S. & DORAN, J.W. Organic matter as a source and sink of plant nutrients. In: COLEMAN, D.C.; OADES, J.M. & UEHARA, G., eds. Dynamics of soil organic matter in tropical ecosystems. Honululu, University of Hawaii Press, 1989. p.33-68.

[9] INOBUSHI, K.; BROOKES, P.C. & JENKINSON, D.S. Soil microbial biomass C, N, and ninhydrin-N in aerobic and anaerobic soils measured by the fumigation-extraction method. Soil Biol. Biochem., 23:737-741, 1991.

[10] JOERGENSEN, R.G. & BROOKES, P.C. Ninhydrin-reactive nitrogen measurements of microbial biomass in 0.5 M K₂SO₄ soil extracts. Soil Biol. Biochem., 22:1023-1027, 1990.

[11] NHEIDHARDT, F.C.; INGRAHAM, J.L. & SCHAECHTER, M. Biosynthesis and fuelling. In: Physiology of the bacterial cell: a molecular approach. Massachusetts, Sinauer Publishers, 1990. p.133-173.

[12] SPARLING, G.P.; GUPTA, V.V.S.R. & ZHU, C. Release of ninhydrin-reactive compounds during fumigation of soil to estimate microbial C and N. Soil Biol. Biochem., 25:1083-1085, 1993.

[13] TEDESCO, M.J.; GIANELLO, C.; BISSANI, C.; BOHNEN, H. & VOLKWEISS, S.J. Análises de solo, plantas e outros materiais. 2 ed. Porto Alegre, Universidade Federal do Rio Grande do Sul, 1995. 174p. (Boletim Técnico, 5)

[14] VANCE, E.D.; BROOKES, P.C. & JENKINSON, D.S. An extraction method for measuring soil microbial biomass C. Soil Biol. Biochem., 19:697-702, 1987.