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Registro Completo |
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Biblioteca(s): |
Embrapa Semiárido; Embrapa Unidades Centrais. |
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Data corrente: |
24/02/2014 |
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Data da última atualização: |
21/10/2015 |
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Autoria: |
BARICELO, L. G.; BACHA, C. J. C. |
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Título: |
Oferta e demanda de máquinas agrícolas no Brasil. |
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Ano de publicação: |
2013 |
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Fonte/Imprenta: |
Revista de Política Agrícola, Brasília, DF, ano 22 , n. 4, p. 67-83, out./nov./dez. 2013. |
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Idioma: |
Português |
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Conteúdo: |
O objetivo deste artigo é analisar os principais impactos das políticas econômicas e agrícolas sobre a oferta e a demanda de máquinas agrícolas no Brasil, dando atenção especial aos anos de 1995 a 2010. Constata-se, tanto por meio da análise gráfica quanto da análise econométrica, que há relação direta e positiva entre a área plantada e a demanda por máquinas agrícolas, bem como relação inversa entre os preços de máquinas agrícolas e sua demanda. Apesar de o governo federal ter criado o Programa de Modernização da Frota de Tratores Agrícolas e Implementos Associados e Colheitadeiras (Moderfrota) em 2000, e de ter ocorrido aumento da demanda por máquinas agrícolas a partir de então, os resultados das análises gráfica e econométrica não evidenciam relação linear entre esse programa e o aumento da demanda por máquinas agrícolas no Brasil. A demanda reage mais a variações de área (com elasticidade cruzada de 2,72) do que a variações de preços (elasticidade de -1,41). |
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Palavras-Chave: |
Moderfrota. |
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Thesagro: |
Política agrícola; Política econômica. |
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Thesaurus Nal: |
Agricultural policy; Economic policy. |
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Categoria do assunto: |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/98036/1/Oferta-e-demanda-de-maquinas-agricolas-no-Brasil.pdf
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Marc: |
LEADER 01588naa a2200193 a 4500
001 1981006
005 2015-10-21
008 2013 bl uuuu u00u1 u #d
100 1 $aBARICELO, L. G.
245 $aOferta e demanda de máquinas agrícolas no Brasil.
260 $c2013
520 $aO objetivo deste artigo é analisar os principais impactos das políticas econômicas e agrícolas sobre a oferta e a demanda de máquinas agrícolas no Brasil, dando atenção especial aos anos de 1995 a 2010. Constata-se, tanto por meio da análise gráfica quanto da análise econométrica, que há relação direta e positiva entre a área plantada e a demanda por máquinas agrícolas, bem como relação inversa entre os preços de máquinas agrícolas e sua demanda. Apesar de o governo federal ter criado o Programa de Modernização da Frota de Tratores Agrícolas e Implementos Associados e Colheitadeiras (Moderfrota) em 2000, e de ter ocorrido aumento da demanda por máquinas agrícolas a partir de então, os resultados das análises gráfica e econométrica não evidenciam relação linear entre esse programa e o aumento da demanda por máquinas agrícolas no Brasil. A demanda reage mais a variações de área (com elasticidade cruzada de 2,72) do que a variações de preços (elasticidade de -1,41).
650 $aAgricultural policy
650 $aEconomic policy
650 $aPolítica agrícola
650 $aPolítica econômica
653 $aModerfrota
700 1 $aBACHA, C. J. C.
773 $tRevista de Política Agrícola, Brasília, DF, ano 22$gn. 4, p. 67-83, out./nov./dez. 2013.
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Registro original: |
Embrapa Unidades Centrais (AI-SEDE) |
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Registro Completo
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Biblioteca(s): |
Embrapa Instrumentação. |
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Data corrente: |
26/07/2023 |
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Data da última atualização: |
15/01/2024 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
A - 3 |
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Autoria: |
PESSOA, T. N.; FERREIRA, T. R.; PIRES, L. F.; COOPER, M.; UTEAU, D.; PETH, S.; VAZ, C. M. P.; LIBARDI, P. L. |
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Afiliação: |
University of São Paulo-“Luiz de Queiroz” College of Agriculture; Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM); Laboratory of Physics Applied to Soils and Environmental Sciences, State University of Ponta Grossa; Department of Soil Science, University of São Paulo-“Luiz de Queiroz” College of Agriculture; Department of Soil Science, Faculty of Ecological Agriculture, University of Kassel; Institute of Soil Science, Leibniz Universität Hannover; CARLOS MANOEL PEDRO VAZ, CNPDIA; Department of Soil Science, University of São Paulo-“Luiz de Queiroz” College of Agriculture. |
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Título: |
X-ray Microtomography for Investigating Pore Space and Its Relation to Water Retention and Conduction in Highly Weathered Soils. |
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Ano de publicação: |
2023 |
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Fonte/Imprenta: |
Agriculture, v. 13, n. 28, 2023. |
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Páginas: |
14 p. |
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DOI: |
https://doi.org/10.3390/agriculture13010028 |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract: Soil structure controls soil hydraulic properties and is linked to soil aggregation processes. The aggregation processes of Oxisols are controlled mainly by clay mineralogy and biological activity. Computed microtomography (µCT) may be a tool for improving the knowledge of the hydraulic properties of these soils. Thus, this study brings an advance in the use of 3D image analysis to better comprehend the water behavior in tropical soils. In this work, three Oxisols were studied with the objective to (i) characterize the soil water retention curve (SWRC), the corresponding pore size frequency, and the saturated hydraulic conductivity (Ksat); (ii) use µCT to obtain, based on 3D images of soil structure and pore size distribution; and (iii) correlating parameters from SWRCs, Ksat, and µCT with other physical-hydric, chemical, and mineralogical attributes. Rhodic Haplustox—P1, Anionic Acrustox—P2, and Typic Hapludox—P3 were the three studied Oxisols. The differences among the SWRCs were related to the microgranular and block type’s structure morphology, which modified the soil pore space. The pore size frequency was calculated from SWRCs for pores with diameters of 87 ± 2 µm in P1, 134 ± 11µm in P2, and 175 ± 18 µm in P3. Pore size distribution from µCT was determined for the range of 20–100 µm, mainly with the highest percentages: 12 ± 1.09% for P1 and 12 ± 1.4% for P2. Pore connectivity was assessed from images by calculating Euler Numbers (EN), with the differences related to the biggest pore (ENbigpore): P1 (−44,223 ± 10,096) and P2 (−44,621 ± 12,573) showed more connected pores (ENbigpore) in comparison to P3 (−11,597 ± 6935). The parameter ENbigpore was decisive in understanding the water retention and conduction processes of the studied soils. The better-connected pore space increased Ksat in P1 (220 ± 0.05 mm h−1 ) and P2 (189 ± 0.1 mm h−1 ) in comparison to P3 (20 ± 0.3 mm h−1 ) and modified the shape of SWRCs. MenosAbstract: Soil structure controls soil hydraulic properties and is linked to soil aggregation processes. The aggregation processes of Oxisols are controlled mainly by clay mineralogy and biological activity. Computed microtomography (µCT) may be a tool for improving the knowledge of the hydraulic properties of these soils. Thus, this study brings an advance in the use of 3D image analysis to better comprehend the water behavior in tropical soils. In this work, three Oxisols were studied with the objective to (i) characterize the soil water retention curve (SWRC), the corresponding pore size frequency, and the saturated hydraulic conductivity (Ksat); (ii) use µCT to obtain, based on 3D images of soil structure and pore size distribution; and (iii) correlating parameters from SWRCs, Ksat, and µCT with other physical-hydric, chemical, and mineralogical attributes. Rhodic Haplustox—P1, Anionic Acrustox—P2, and Typic Hapludox—P3 were the three studied Oxisols. The differences among the SWRCs were related to the microgranular and block type’s structure morphology, which modified the soil pore space. The pore size frequency was calculated from SWRCs for pores with diameters of 87 ± 2 µm in P1, 134 ± 11µm in P2, and 175 ± 18 µm in P3. Pore size distribution from µCT was determined for the range of 20–100 µm, mainly with the highest percentages: 12 ± 1.09% for P1 and 12 ± 1.4% for P2. Pore connectivity was assessed from images by calculating Euler Numbers (EN), with the differences r... Mostrar Tudo |
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Palavras-Chave: |
Pore connectivity; Pore size distribution; Soil water retention curve. |
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Categoria do assunto: |
-- |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/259608/1/P-X-ray-Microtomography-for-Investigating-Pore-Space-and-Its-Relation-to-Water-Retention-and-Conduction-in-Highly-Weathered-Soils.pdf
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Marc: |
LEADER 02809naa a2200265 a 4500
001 2155317
005 2024-01-15
008 2023 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.3390/agriculture13010028$2DOI
100 1 $aPESSOA, T. N.
245 $aX-ray Microtomography for Investigating Pore Space and Its Relation to Water Retention and Conduction in Highly Weathered Soils.$h[electronic resource]
260 $c2023
300 $a14 p.
520 $aAbstract: Soil structure controls soil hydraulic properties and is linked to soil aggregation processes. The aggregation processes of Oxisols are controlled mainly by clay mineralogy and biological activity. Computed microtomography (µCT) may be a tool for improving the knowledge of the hydraulic properties of these soils. Thus, this study brings an advance in the use of 3D image analysis to better comprehend the water behavior in tropical soils. In this work, three Oxisols were studied with the objective to (i) characterize the soil water retention curve (SWRC), the corresponding pore size frequency, and the saturated hydraulic conductivity (Ksat); (ii) use µCT to obtain, based on 3D images of soil structure and pore size distribution; and (iii) correlating parameters from SWRCs, Ksat, and µCT with other physical-hydric, chemical, and mineralogical attributes. Rhodic Haplustox—P1, Anionic Acrustox—P2, and Typic Hapludox—P3 were the three studied Oxisols. The differences among the SWRCs were related to the microgranular and block type’s structure morphology, which modified the soil pore space. The pore size frequency was calculated from SWRCs for pores with diameters of 87 ± 2 µm in P1, 134 ± 11µm in P2, and 175 ± 18 µm in P3. Pore size distribution from µCT was determined for the range of 20–100 µm, mainly with the highest percentages: 12 ± 1.09% for P1 and 12 ± 1.4% for P2. Pore connectivity was assessed from images by calculating Euler Numbers (EN), with the differences related to the biggest pore (ENbigpore): P1 (−44,223 ± 10,096) and P2 (−44,621 ± 12,573) showed more connected pores (ENbigpore) in comparison to P3 (−11,597 ± 6935). The parameter ENbigpore was decisive in understanding the water retention and conduction processes of the studied soils. The better-connected pore space increased Ksat in P1 (220 ± 0.05 mm h−1 ) and P2 (189 ± 0.1 mm h−1 ) in comparison to P3 (20 ± 0.3 mm h−1 ) and modified the shape of SWRCs.
653 $aPore connectivity
653 $aPore size distribution
653 $aSoil water retention curve
700 1 $aFERREIRA, T. R.
700 1 $aPIRES, L. F.
700 1 $aCOOPER, M.
700 1 $aUTEAU, D.
700 1 $aPETH, S.
700 1 $aVAZ, C. M. P.
700 1 $aLIBARDI, P. L.
773 $tAgriculture$gv. 13, n. 28, 2023.
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Embrapa Instrumentação (CNPDIA) |
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