Funções de pedotransferência para a curva de resistência do solo à penetração
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Data
2008-12-01
Autores
Almeida, Cinara Xavier de [UNESP]
Centurion, José Frederico [UNESP]
Freddi, Onã da Silva [UNESP]
Jorge, Ricardo Falqueto [UNESP]
Barbosa, José Carlos [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Ciência do Solo
Resumo
A estimativa da curva de resistência do solo à penetração (CRP) a partir de variáveis de fácil obtenção, como o conteúdo de água, representa uma medida útil não só para a quantificação do estado de compactação, mas também para facilitar a interpretação da resistência do solo à penetração obtida em diferentes condições de campo. O objetivo deste trabalho foi estimar a CRP em solos de diferentes granulometrias e densidades, a partir de dados obtidos com o penetrômetro de impacto. O experimento foi realizado no laboratório de Pedologia da Faculdade de Ciências Agrárias e Veterinárias (UNESP), Jaboticabal, SP. Foram utilizadas quatro classes de solos: Neossolo Quartzarênico, Argissolo Vermelho-Amarelo, Latossolo Vermelho distrófico e Latossolo Vermelho acriférrico, os quais foram coletados na camada de 0-0,20 m. Colunas de PVC, com dimensões de 0,25 m de diâmetro e 0,6 m de altura, foram preenchidas de forma a obter duas condições de compactação: menor densidade e maior densidade do solo. O conteúdo de água nos solos, inicialmente elevado até o ponto de saturação, foi monitorado diariamente por meio de um medidor eletrônico tipo TDR (Profile Probe PR2 acoplado ao Moisture Meter HH2). A resistência do solo à penetração foi mensurada por meio de um penetrômetro de impacto adaptado para vaso. Os pares de dados entre a resistência do solo à penetração e o conteúdo de água foram ajustados, e as CRP foram submetidas ao teste de significância. A relação entre a resistência do solo à penetração e o conteúdo de água foi descrita pelo modelo exponencial decrescente: em que RP representa a resistência do solo à penetração (MPa); Ug é o conteúdo de água (kg kg-1); e A, B e C são os coeficientes da equação. Foram obtidos coeficientes de determinação que variaram de 0,79 a 0,96.
The estimate soil resistance to penetration curves (RPC) based on readily obtained variables such as water content, is a useful not only for the evaluation of soil compaction, but also to simplify the interpretation of soil resistance to penetration under different field conditions. The objective of this study was to estimate the RPC in soils of different textures and bulk densities based on data obtained with an impact penetrometer. The experiment was carried out at the Faculdade de Ciências Agrárias e Veterinárias (UNESP), Jaboticabal, SP. Four soil classes were used: Entissol, Alfissol, Oxisol sandy loam and clayey Oxisol, which were sampled at a depth of 0-0.20 m. The PVC columns (diameter 0.25 m, height 0.6 m) were filled to represent non compacted and compacted soil. The soil water content, initially elevated to the saturation point, was monitored daily with a TDR device (Profile Probe PR2 connected to a HH2 Moisture Meter). The soil resistance to penetration was measured by an impact penetrometer adapted to be used in the pot. The soil resistance to penetration and water content data pairs were adjusted and the RPC submitted to a significance test. The relationship between the soil resistance to penetration and soil water content was best described by the exponential equation: where RP is the soil resistance to penetration (MPa), Vg soil water content (kg kg-1) and A, B and C are the equation parameters. There was a significant relation between soil resistance to penetration and water content and the equations fit the data with coefficients of determination ranging from 0.79 to 0.96.
The estimate soil resistance to penetration curves (RPC) based on readily obtained variables such as water content, is a useful not only for the evaluation of soil compaction, but also to simplify the interpretation of soil resistance to penetration under different field conditions. The objective of this study was to estimate the RPC in soils of different textures and bulk densities based on data obtained with an impact penetrometer. The experiment was carried out at the Faculdade de Ciências Agrárias e Veterinárias (UNESP), Jaboticabal, SP. Four soil classes were used: Entissol, Alfissol, Oxisol sandy loam and clayey Oxisol, which were sampled at a depth of 0-0.20 m. The PVC columns (diameter 0.25 m, height 0.6 m) were filled to represent non compacted and compacted soil. The soil water content, initially elevated to the saturation point, was monitored daily with a TDR device (Profile Probe PR2 connected to a HH2 Moisture Meter). The soil resistance to penetration was measured by an impact penetrometer adapted to be used in the pot. The soil resistance to penetration and water content data pairs were adjusted and the RPC submitted to a significance test. The relationship between the soil resistance to penetration and soil water content was best described by the exponential equation: where RP is the soil resistance to penetration (MPa), Vg soil water content (kg kg-1) and A, B and C are the equation parameters. There was a significant relation between soil resistance to penetration and water content and the equations fit the data with coefficients of determination ranging from 0.79 to 0.96.
Descrição
Palavras-chave
Compaction, Soil water content, soil physical quality, compactação, Conteúdo de água, Qualidade física do solo
Como citar
Revista Brasileira de Ciência do Solo. Sociedade Brasileira de Ciência do Solo, v. 32, n. 6, p. 2235-2243, 2008.