| |
|
|
 | Acesso ao texto completo restrito à biblioteca da Embrapa Solos. Para informações adicionais entre em contato com cnps.biblioteca@embrapa.br. |
|
Registro Completo |
|
Biblioteca(s): |
Embrapa Solos. |
|
Data corrente: |
15/04/2004 |
|
Data da última atualização: |
25/10/2020 |
|
Autoria: |
MACHADO, P. L. O. de A.; SOHI, S. P.; GAUNT, J. L. |
|
Afiliação: |
PEDRO LUIZ OLIVEIRA DE A MACHADO, CNPS. |
|
Título: |
Effect of no-tillage on turnover of organic matter in a Rhodic Ferralsol. |
|
Ano de publicação: |
2003 |
|
Fonte/Imprenta: |
Soil Use and Management, v. 19, n. 3, p. 250-256, Sept. 2003. |
|
DOI: |
https://doi.org/10.1111/j.1475-2743.2003.tb00311.x |
|
Idioma: |
Inglês |
|
Conteúdo: |
Soil organic matter (SOM) is considered to be key to sustainability of agriculture in the tropics. In southern Brazil, no-tillage has been adopted widely to control soil erosion, but its impact on the dynamics of SOM is not well established. We measured soil carbon (C) and d13C in two crop rotations, one of which contained C4 maize (Zea mays L.), after 21 years of contrasting tillage (conventional tillage versus no-tillage). Adjacent sites that reflected historic land-uses were also sampled. In the tillage experiment there was no effect of tillage on the total amount of C in the 0-40 cm profile (even when contrasting bulk density was accounted for), and the concentration of C differed only in the 0-5 cm and 5-10 cm layers. However, the occasional input of C4 material in the maize rotation resulted in a significant effect of rotation on d13C (P <0.001). Using 13C as a tracer for the SOM formed since the start of the experiment, we estimated the abundance of 'recent' and 'old' C within each depth interval. We found the main effect of tillage was to increase the medium-term turnover of SOM, particularly in the subsoil (i.e. below 20 cm depth). Compared with no-tillage, there was almost five times more recent C in the subsoil, and 20% more recent C in the 0?40 cm profile as a whole. |
|
Thesagro: |
Ferralsolo; Matéria Orgânica; Plantio Direto. |
|
Thesaurus Nal: |
Ferralsols; No-tillage; Soil organic matter. |
|
Categoria do assunto: |
P Recursos Naturais, Ciências Ambientais e da Terra |
|
Marc: |
LEADER 02004naa a2200229 a 4500
001 1335978
005 2020-10-25
008 2003 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.1111/j.1475-2743.2003.tb00311.x$2DOI
100 1 $aMACHADO, P. L. O. de A.
245 $aEffect of no-tillage on turnover of organic matter in a Rhodic Ferralsol.$h[electronic resource]
260 $c2003
520 $aSoil organic matter (SOM) is considered to be key to sustainability of agriculture in the tropics. In southern Brazil, no-tillage has been adopted widely to control soil erosion, but its impact on the dynamics of SOM is not well established. We measured soil carbon (C) and d13C in two crop rotations, one of which contained C4 maize (Zea mays L.), after 21 years of contrasting tillage (conventional tillage versus no-tillage). Adjacent sites that reflected historic land-uses were also sampled. In the tillage experiment there was no effect of tillage on the total amount of C in the 0-40 cm profile (even when contrasting bulk density was accounted for), and the concentration of C differed only in the 0-5 cm and 5-10 cm layers. However, the occasional input of C4 material in the maize rotation resulted in a significant effect of rotation on d13C (P <0.001). Using 13C as a tracer for the SOM formed since the start of the experiment, we estimated the abundance of 'recent' and 'old' C within each depth interval. We found the main effect of tillage was to increase the medium-term turnover of SOM, particularly in the subsoil (i.e. below 20 cm depth). Compared with no-tillage, there was almost five times more recent C in the subsoil, and 20% more recent C in the 0?40 cm profile as a whole.
650 $aFerralsols
650 $aNo-tillage
650 $aSoil organic matter
650 $aFerralsolo
650 $aMatéria Orgânica
650 $aPlantio Direto
700 1 $aSOHI, S. P.
700 1 $aGAUNT, J. L.
773 $tSoil Use and Management$gv. 19, n. 3, p. 250-256, Sept. 2003.
Download
Esconder MarcMostrar Marc Completo |
|
Registro original: |
Embrapa Solos (CNPS) |
|
|
Biblioteca |
ID |
Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
URL |
Voltar
|
|
|
| Acesso ao texto completo restrito à biblioteca da Embrapa Agricultura Digital. Para informações adicionais entre em contato com cnptia.biblioteca@embrapa.br. |
Registro Completo
|
Biblioteca(s): |
Embrapa Agricultura Digital. |
|
Data corrente: |
30/09/1996 |
|
Data da última atualização: |
18/02/2011 |
|
Autoria: |
NASCIMENTO, M. A.; DUNHAM, M. H.; KOURAMAJIAN, V. |
|
Afiliação: |
MARIO A. NASCIMENTO, CNPTIA; MARGARET H. DUNHAM, Southern Methodist University; VRAM KOURAMAJIAN, Wichita State University. |
|
Título: |
A mapping-based approach for range indexing. |
|
Ano de publicação: |
1995 |
|
Fonte/Imprenta: |
Dallas: Southern Methodist University, 1995. |
|
Páginas: |
27 p. |
|
Série: |
(Technical Report, 95-CSE-14). |
|
Idioma: |
Inglês |
|
Conteúdo: |
In this paper we present an indexing structure for ranges. The main idea is to map a bounded range to a point in one-dimensional space, using a standard B+-tree to index such a point. The indexing structure is storage-wise efficient, requiring O(N), where N is the number of indexed ranges. Its maintainance is also efficient, requiring O(log N) accesses per update. We also show that it is able to efficaciously answer a number of different queries, requiring, for instance, O(log N + L) I/Os to answer an intersection type of query, where L is the length of the range given in the query. An analytical performance study is also presented. Finally, we point out two immediate applications of this indexing approach, which are (1) answering stabbing queries and (2) the indexing of a valid-time (historical) database. |
|
Palavras-Chave: |
Algoritmo; Árvore B+-; Bases de dados histórica; Indexação. |
|
Thesaurus NAL: |
Algorithms; Databases. |
|
Categoria do assunto: |
X Pesquisa, Tecnologia e Engenharia |
|
Marc: |
LEADER 01419nam a2200229 a 4500
001 1003669
005 2011-02-18
008 1995 bl uuuu t 00u1 u #d
100 1 $aNASCIMENTO, M. A.
245 $aA mapping-based approach for range indexing.
260 $aDallas: Southern Methodist University$c1995
300 $a27 p.
490 $a(Technical Report, 95-CSE-14).
520 $aIn this paper we present an indexing structure for ranges. The main idea is to map a bounded range to a point in one-dimensional space, using a standard B+-tree to index such a point. The indexing structure is storage-wise efficient, requiring O(N), where N is the number of indexed ranges. Its maintainance is also efficient, requiring O(log N) accesses per update. We also show that it is able to efficaciously answer a number of different queries, requiring, for instance, O(log N + L) I/Os to answer an intersection type of query, where L is the length of the range given in the query. An analytical performance study is also presented. Finally, we point out two immediate applications of this indexing approach, which are (1) answering stabbing queries and (2) the indexing of a valid-time (historical) database.
650 $aAlgorithms
650 $aDatabases
653 $aAlgoritmo
653 $aÁrvore B+-
653 $aBases de dados histórica
653 $aIndexação
700 1 $aDUNHAM, M. H.
700 1 $aKOURAMAJIAN, V.
Download
Esconder MarcMostrar Marc Completo |
|
Registro original: |
Embrapa Agricultura Digital (CNPTIA) |
|
|
Biblioteca |
ID |
Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
Fechar
|
| Expressão de busca inválida. Verifique!!! |
|
|
