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Registro Completo |
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Biblioteca(s): |
Embrapa Pantanal. |
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Data corrente: |
03/09/1996 |
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Data da última atualização: |
04/04/2017 |
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Autoria: |
SPARLING, G. P.; MURPHY, D. V.; THOMPSON, R. B.; FILLERY, I. R. P. |
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Título: |
Short-term net N mineralization from plant residues and gross and net N mineralization from soil organic matter after rewetting of a seasonally dry soil. |
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Ano de publicação: |
1995 |
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Fonte/Imprenta: |
Australian Journal Soil of Research, v.33, n.6, p.961-973, 1995. |
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Idioma: |
Inglês |
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Conteúdo: |
The mineralization of N from shoot residues of two legume species and a common weed component of Western Australian pastures was measured after a simulated summer rainfall in a laboratory experiment using undisturbed soil cores of a loamy sand. Water was added to the surface of the cores equivalent to a single rainfall event of 10 mm water (treatment 1); or followed 48 h later by a further application of 10 mm water (treatment 2). Net mineralization and microbial biomass N were measured over 144 h following the initial rewetting of the soil cores. Threes types of 15N-labelled plant residue, namely (i) lupin leaf (Lupinus angustifolium), (ii) clover (Trifolium subterraneum) shoot, burr and petiole, and (iii) capeweed (Arctotheca calendula) shoots and leaves were placed on the soil surface as large fragments and examined to asses their mineralization and incorporation into microbial biomass. The soils dried rapidly after rewetting and net mineralization of N was very low. The proportion of N as nitrate was increased in the rewetted soils with the major changes occurring in the top 5 cm of soil. However, there was very little mineralization of the surface-applied plant residues, with more than 90% of the mineral N being derived from the native organic matter. Microbial biomass showed fluctuations in both the rewetted treatments, but no consistent increase or decrease and no significant immobilization of 15N. Gross N mineralization was measured using an isotopic dilution technique involving the injection of 15N-labelled solutions into the soil. Estimates of gross N mineralization after a single rainfall event of 10 mm water were, on average, four times greather than measures of net N mineralization. Gross N mineralization rates declined as the soil dried, with three times more mineralization occurring in the 0-5 cm depth (4.73-8.93 ug g-1 day-1), compared with the 5-10 cm depth (0.86-2.38 ug g-1 day-1). A major disadvantage with the isotopic dilution method was that injection of the solutions into soil greatly increased the soil moisture content. Gross mineralization in the injected cores is likely to have been overestimated because of N movement below the sampling zone and increased microbial activity relative to non-injected cores. MenosThe mineralization of N from shoot residues of two legume species and a common weed component of Western Australian pastures was measured after a simulated summer rainfall in a laboratory experiment using undisturbed soil cores of a loamy sand. Water was added to the surface of the cores equivalent to a single rainfall event of 10 mm water (treatment 1); or followed 48 h later by a further application of 10 mm water (treatment 2). Net mineralization and microbial biomass N were measured over 144 h following the initial rewetting of the soil cores. Threes types of 15N-labelled plant residue, namely (i) lupin leaf (Lupinus angustifolium), (ii) clover (Trifolium subterraneum) shoot, burr and petiole, and (iii) capeweed (Arctotheca calendula) shoots and leaves were placed on the soil surface as large fragments and examined to asses their mineralization and incorporation into microbial biomass. The soils dried rapidly after rewetting and net mineralization of N was very low. The proportion of N as nitrate was increased in the rewetted soils with the major changes occurring in the top 5 cm of soil. However, there was very little mineralization of the surface-applied plant residues, with more than 90% of the mineral N being derived from the native organic matter. Microbial biomass showed fluctuations in both the rewetted treatments, but no consistent increase or decrease and no significant immobilization of 15N. Gross N mineralization was measured using an isotopic dilution techniq... Mostrar Tudo |
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Palavras-Chave: |
Mirobial biomass. |
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Thesagro: |
Matéria Orgânica; Mineralização; Nitrogênio; Solo. |
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Thesaurus Nal: |
mineralization; nitrogen; organic matter; soil. |
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Categoria do assunto: |
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Marc: |
LEADER 03065naa a2200265 a 4500
001 1789564
005 2017-04-04
008 1995 bl --- 0-- u #d
100 1 $aSPARLING, G. P.
245 $aShort-term net N mineralization from plant residues and gross and net N mineralization from soil organic matter after rewetting of a seasonally dry soil.
260 $c1995
520 $aThe mineralization of N from shoot residues of two legume species and a common weed component of Western Australian pastures was measured after a simulated summer rainfall in a laboratory experiment using undisturbed soil cores of a loamy sand. Water was added to the surface of the cores equivalent to a single rainfall event of 10 mm water (treatment 1); or followed 48 h later by a further application of 10 mm water (treatment 2). Net mineralization and microbial biomass N were measured over 144 h following the initial rewetting of the soil cores. Threes types of 15N-labelled plant residue, namely (i) lupin leaf (Lupinus angustifolium), (ii) clover (Trifolium subterraneum) shoot, burr and petiole, and (iii) capeweed (Arctotheca calendula) shoots and leaves were placed on the soil surface as large fragments and examined to asses their mineralization and incorporation into microbial biomass. The soils dried rapidly after rewetting and net mineralization of N was very low. The proportion of N as nitrate was increased in the rewetted soils with the major changes occurring in the top 5 cm of soil. However, there was very little mineralization of the surface-applied plant residues, with more than 90% of the mineral N being derived from the native organic matter. Microbial biomass showed fluctuations in both the rewetted treatments, but no consistent increase or decrease and no significant immobilization of 15N. Gross N mineralization was measured using an isotopic dilution technique involving the injection of 15N-labelled solutions into the soil. Estimates of gross N mineralization after a single rainfall event of 10 mm water were, on average, four times greather than measures of net N mineralization. Gross N mineralization rates declined as the soil dried, with three times more mineralization occurring in the 0-5 cm depth (4.73-8.93 ug g-1 day-1), compared with the 5-10 cm depth (0.86-2.38 ug g-1 day-1). A major disadvantage with the isotopic dilution method was that injection of the solutions into soil greatly increased the soil moisture content. Gross mineralization in the injected cores is likely to have been overestimated because of N movement below the sampling zone and increased microbial activity relative to non-injected cores.
650 $amineralization
650 $anitrogen
650 $aorganic matter
650 $asoil
650 $aMatéria Orgânica
650 $aMineralização
650 $aNitrogênio
650 $aSolo
653 $aMirobial biomass
700 1 $aMURPHY, D. V.
700 1 $aTHOMPSON, R. B.
700 1 $aFILLERY, I. R. P.
773 $tAustralian Journal Soil of Research$gv.33, n.6, p.961-973, 1995.
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Registro original: |
Embrapa Pantanal (CPAP) |
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