Comparação de penetrômetros na avaliação da compactação de latossolos

Abstract

RESUMO:Diversos penetrômetros são utilizados para avaliar a resistência do solo à penetração em sistemas de uso e manejo, no entanto os valores obtidos com os mesmos divergem. O objetivo deste estudo foi comparar os resultados obtidos com três penetrômetros, em três níveis de compactação. Utilizou-se de um Latossolo Vermelho distrófico (LVd), textura média, e um Latossolo Vermelho eutroférrico (LVef), textura argilosa, cujas amostras foram coletadas na camada de 0-20 cm e compactadas em camadas, em vasos de 25 cm de diâmetro e 20 cm de altura. Determinou-se a resistência do solo à penetração com os penetrômetros de impacto, estático de anel dinamométrico e eletrônico de laboratório. Em solo compactado, o penetrômetro de impacto apresentou valores superiores de resistência à penetração, comparado aos penetrômetros de anel dinamométrico e eletrônico, porém todos foram eficientes para caracterizar a compactação. Os resultados obtidos com os penetrômetros de anel dinamométrico e eletrônico foram semelhantes. PALAVRAS-CHAVE:resistência à penetração, atributos físicos do solo, conteúdo de água. COMPARISON OF PENETROMETERS TO EVALUATE SOIL COMPACTNESS IN OXISOLSABSTRACT: Several penetrometers have been used to evaluate soil resistance to penetration in tillage systems. However, the values obtained with them, diverge. This research was carried out with the objective of comparing results obtained with three penetrometers in three levels of compactness, using soil samples collected at 0-20 cm depth of an Oxisol (Haplustox) (LVd), medium texture, an Oxisol (Eutrustox) (LVef) and clayey texture. The soils were compacted in layers, in pots of 25 cm diameter and 20 cm height. Soil resistance to penetration with impact and and electronic dynamometrical ring penetrometers were determined. The impact penetrometer presented superior values of resistance to penetration in relation to the static and electronic dynamometrical ring penetrometers; moreover all were efficient to characterize soil compactness. The results obtained with the ring penetrometer and eletronic penetrometers were similar.

Caracterização de solos sob diferentes usos na região sul do Amazonas

“…Nesse contexto, o conteúdo de água na capacidade de campo é considerado ideal para a determinação da RSP, condição em que é obtida melhor correlação com a densidade do solo (Henderson 1989). Beutler et al (2007), encontraram correlação positiva entre a RSP e Ds na comparação de penetrômetros usados para a avaliação da compactação de Latossolos.…”

Penetration resistance in a latosol under different moisture and penetration speeds

“…However, Sojka et al (2001) reported that, besides the use of instruments to measure the cone penetration into the soil is very common as a physical characterization method, such determinations are rarely followed by another information that allows to quantify how obtained cone index values are influenced by other parameters related with physical properties of each soil. Moreover, as found by Beutler et al (2007), different equipments can produce distinct results under the same conditions, although indicate equivalent tendencies. The authors noticed that these results are related with devices construction characteristics, even though the cone used in the measurements were standardized.…”

Development of an automated bench top electronic penetrometer

“…The results obtained for the interaction between velocity and BAC suggest the need for future studies involving these two variables, seeking to minimize its effects on the CI for the purpose of standardization of penetrometry tests in bench tops (laboratory). The influence of the base area of the cone in the values of CI is of concern, because there are no criteria or standards established for conducting this type of test, and researchers have recently used cones of different angles and base areas (GELAIN et al, 2011;PACHECO, 2010;FRANCO, 2010, andBEUTLER et al, 2007). The velocity of penetration also influenced the obtained CI, as it was observed from the results presented in Table 2.…”

“…The performance test involved the assessment of soil resistance to penetration with two cones of different base areas (C1 = 11,05 mm 2 and C2 = 34,21 mm 2 ), and two velocities of cone penetration (V1 = 10mm min-1 or 0.1667mm s-1 and V2 = 30mm s-1). The V1 was chosen because it is the velocity used in most studies developed with bench top penetrometers (GELAIN et al (2011);BERGAMIN et al (2010); PACHECO & CATALICE (2011);SERAFIM et al (2008);BEUTLER et al (2007). The V2 corresponds to the standard velocity established by the ASABE-ASAE, 1998, for field tests.…”

“…BERGAMIN et al (2010) and GELAIN et al (2011) used an electronic penetrometer developed by SERAFIM et al (2008), with a constant velocity of penetration of 0.1667 mm s -1 , a base area of the cone of 12.56mm², and a 60° angle. The study developed by BEUTLER et al (2007) used a laboratory static electronic penetrometer with a constant velocity of penetration of 0.1667 mm s -1 and a base area of the cone (BAC) of 3.7mm 2 .…”