Determinação da permeabilidade ao ar em amostras indeformadas de solo pelo método da pressão decrescente

Silva, Álvaro Pires da; Leão, Tairone Paiva; Tormena, Cássio Antônio; Gonçalves, Antônio Carlos Andrade

doi:10.1590/s0100-06832009000600003

Cited by 17 publications

(20 citation statements)

References 32 publications

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“…These results support the claim of Silva et al (2009) that Ɛ a may not reflect in precise measurements of the behavior of gases in the soil for measuring the volume and not taking pore continuity into consideration, which is more important for the soil air flow. Aeration is a dynamic process and is dependent on other factors, e.g., the saturation degree (Juca & Maciel, 2006), wetting/drying process (Kamiya et al, 2006) Considering that sowing is the only tillage operation in NT, it is hardly surprising that the conditions in terms of BD and K a are best in the CR position, as this is the point of action of the cutting discs and furrow opener for seed and fertilizer deposition, which also break the compacted layer.…”

Section: Resultssupporting

confidence: 84%

“…Ball et al (1988), Blackwell et al (1990), Dörner & Horn (2006) and Groenevelt et al (1984) used the relationships between K a and Ɛ a to estimate indexes of pore continuity that characterize functional changes in the soil pore system. In Brazil, Silva et al (2009) (Ball & Robertson, 1994;Rodrigues et al, 2011). However, these studies of near surface soils ignore spatial locations when obtaining samples in the field.…”

Section: Introductionmentioning

confidence: 99%

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Aeration condition of a clayey oxisol under long-term no-tillage

Betioli

Tormena²,

Moreira

et al. 2014

Rev. Bras. Ciênc. Solo

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The hypothesis of this study was that the absence of soil tillage in long-term no-tillage (NT) systems can be detrimental to soil aeration. The objective was to assess the aeration condition of an Oxisol (Rhodic Ferrasol), very clayey texture (750 g kg-1 of clay; 200 g kg-1 of sand), after 30 years of cultivation under NT. The physical property soil air permeability (Ka) is sensitive to changes in the soil pore system. Aside from Ka, the air-filled porosity (ε a) and indices of pore continuity (K1 and N), derived from the relationship between Ka and εa, were used as indices of soil aeration. From the soil layers 0.0-0.1 and 0.1-0.2 m, 240 undisturbed samples were collected along a transect perpendicular to the crop rows, at three sampling positions: corn plant row (CR); center of the interrow (INT); and the equidistant point between CR and INT (PE). The properties Ka and εa were determined at soil matric potentials (Ψm) of -2, -4, -6, -10, -30, and -50 kPa. Soil bulk density (BD) was also determined. The results confirmed the hypothesis. In the 0.0-0.1 m layer, Ka, K1, N and Ψa were significantly greater and BD significantly lower in CR than at the other sampling positions. At a Ψm of -10 kPa, the Ka of CR was 6.9 and 8.4 times higher than in PE and INT, respectively, in the 0.0-0.1 m layer. The properties Ka, K1 and N were sensitive enough to detect changes in the pore system and their differences between the sampling positions demonstrated the importance of the spatial location for soil sampling. Tilling the crop rows provides better soil aeration under NT.

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Section: Resultssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Aeration condition of a clayey oxisol under long-term no-tillage

Betioli

Tormena²,

Moreira

et al. 2014

Rev. Bras. Ciênc. Solo

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“…Alguns estudos têm definido a K a como dependente da estrutura do solo (IVERSEN et al, 2001;TULI et al, 2005;SILVA et al, 2009), influenciada pela Pt, distribuição e geometria do sistema poroso, tortuosidade, conectividade e constrição (MOLDRUP et al, 2003;DORNER;. Mais precisamente, a K a é condicionada em relação ao tamanho e continuidade dos Ma, considerados até mesmo mais importantes do que a quantidade de poros na determinação do fluxo de ar (BALL et al, 1988) e, portanto, sendo comum apresentar-se elevada nas camadas mais superficiais.…”

Section: Discussionunclassified

“…É provável ainda que, nessas camadas, ocorram caminhos preferenciais, devido à presença de raízes lignificadas e à atividade da fauna edáfica (SILVA et al, 2009).…”

Section: Discussionunclassified

“…Portanto, o valor da permeabilidade ao ar aumentou devido à redução no teor de água da amostra de solo, fato que pode estar associado à maior proporção de poros vazios e à formação de caminhos preferenciais para o escoamento do ar à medida que os poros de tamanho menores foram sendo progressivamente drenados (SILVA et al, 2009). Enfim, o máximo valor de permeabilidade ao ar é alcançado quando o solo está seco, diminuindo com seu umedecimento até valores próximos de zero, quando ocorre a saturação (BALL; SCHJØNNING, 2002).…”

Section: Discussionunclassified

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IMPACTO DO FLORESTAMENTO COM Pinus taeda L. NA POROSIDADE E PERMEABILIDADE DE UM CAMBISSOLO HÚMICO1

et al. 2015

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RESUMO -O objetivo deste estudo foi avaliar a influência da introdução da espécie Pinus taeda L. nas propriedades físicas e qualidade de um Cambissolo Húmico de campo nativo. O trabalho foi realizado no Município de Cambará do Sul, RS, Brasil. Para isso, foram escolhidas duas áreas, uma em primeira rotação (RT1) e a outra em segunda rotação (RT2). Em cada povoamento foi avaliada conjuntamente, como testemunha, uma área de campo nativo adjacente. Em cada área foram abertas cinco trincheiras e coletadas amostras de solo em quatro camadas até 0,60 m de profundidade. As alterações nas propriedades físicas foram analisadas, avaliando-se: a granulometria, densidade e espaço poroso do solo, a condutividade hidráulica do solo saturado e a permeabilidade do solo ao ar. A estratégia de análise estatística foi comparar os dados referentes à RT1 e RT2 com as respectivas testemunhas, CN1 e CN2, comparando também as médias pelo teste "t", de Student. A implantação de povoamentos de pinus não alterou a densidade nem a porosidade total, mas proporcionou aumentos médios de 145%, 436% e 172%, respectivamente, na macroporosidade, condutividade hidráulica e permeabilidade do solo ao ar na RT1 em relação ao CN1 na camada de 0,0-0,20 m e, respectivamente, de 157%, 640% e 111% para as mesmas variáveis da RT2 em relação ao CN2, na camada de 0,0-0,05 m. O povoamento com pinus melhorou a qualidade do solo, no que se refere à permeabilidade à água e ao ar.Palavras-chave: Estrutura do solo; Condutividade hidráulica; Funcionalidade de poros. IMPACT OF AFFORESTATION WITH Pinus taeda L. IN POROSITY AND PERMEABILITY OF A HAPLUMBREPTABSTRACT -The aim of this study was to evaluate the influence of the introduction of Pinus taeda L. in the physical properties and quality of a Haplumbrept, under native grassland. The study was conducted in Cambará do Sul-RS, Brazil. For this, two areas were chosen, one in first rotation (RT1) and the other in second rotation (RT2). For each stand one area of adjacent native grassland was evaluated jointly, as control. In each area, 5 trenches were opened and soil samples were collected in four layers up to 0.60 m deep. Changes in physical properties were analyzed by determining particle size, density and pore space of soil, saturated soil hydraulic conductivity and permeability of soil to air. The strategy of statistical analysis was to compare the data on RT1 and RT2 with their respective controls, CN1 and CN2, also comparing means by Student "t" test. The deployment of pine stands did not alter the density or total porosity, but provided average increases 1

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Changes in Physical Properties of Soils with Land Use Time in the Brazilian Savanna Environment

2013

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Soils from central Brazil have been intensively used over the last decades because of the rapid conversion of savannas (Cerrado) into corn/soybean fields. The objective of this work is to study modifications in the physical properties of soils in the Rio Verde watershed, as a function of the land use time for agriculture, determined from classification of Landsat satellite images between 1980 and 2010. Soil samples were collected at surface (0-20 cm) and subsurface (20-40 cm) horizons for the different classes of land use time (<10, 10-20, 20-30, and >30 years). The following physical properties were measured: bulk density (BD), air permeability (K a ), penetration resistance (PR), microporosity (MI), macroporosity (MA), and total porosity (TP). Results showed a strong expansion with time of agriculture that occupied 35Á3% (1980), 37Á4% (1990), 51Á3% (2000), and 60Á9% (2010) of the watershed area. When properties were compared with those from the reference areas (preserved soils under native vegetation), significant differences were observed for all the physical attributes of soils for a land use time higher than 20 years. Overall, BD and PR increased with land use time, and the opposite was verified for K a , MA, and TP. Some physical properties presented values (e.g., 1Á54 g cm À3 for BD and 0.06 cm 3 cm À3 for MA) close to the critical ones reported to affect crop development, but they were not still impacting on local soybean yield.

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Determinação da permeabilidade ao ar em amostras indeformadas de solo pelo método da pressão decrescente

Cited by 17 publications

References 32 publications

Aeration condition of a clayey oxisol under long-term no-tillage

Aeration condition of a clayey oxisol under long-term no-tillage

IMPACTO DO FLORESTAMENTO COM Pinus taeda L. NA POROSIDADE E PERMEABILIDADE DE UM CAMBISSOLO HÚMICO1

Changes in Physical Properties of Soils with Land Use Time in the Brazilian Savanna Environment

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