Intervalo hídrico ótimo para avaliação da degradação física do solo

Guimarães, Rachel Muylaert Locks; Tormena, Cássio Antônio; Blainski, Éverton; Fidalski, Jonez

doi:10.1590/s0100-06832013000600008

Cited by 25 publications

(25 citation statements)

References 53 publications

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“…The aeration porosity was lower than the field capacity at density values greater than 1.80 Mg m ( Figure 1B, D, F, H). These values are similar to those found by Guimarães et al (2013) who used the LLWR to assess physical degradation of an Oxisol under native forest, pasture, citrus and annual crops, and found LLWR variations between 0.00 and 0.070 m 3 m -3 .…”

Section: The Least Limiting Water Range (Llwr)supporting

confidence: 87%

“…This behavior differs from T 2 since the θ AP was lower than θ FC for BD> 1.20 Mg m -3 , reducing the LLWR at lower density, indicating a greater change in soil structure due to the higher number of crop cycles with mechanized harvests. Guimarães et al (2013) studied the connection between LLWR and the physical degradation of dystrophic Oxisols and observed that the porosity decreased with increasing density, but did not limit the soils. The aeration porosity was lower than the field capacity at density values greater than 1.80 Mg m ( Figure 1B, D, F, H).…”

Section: The Least Limiting Water Range (Llwr)mentioning

confidence: 99%

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Physical attributes and limiting water range as soil quality indicators after mechanical harvesting of sugarcane

Filho¹,

Souza²,

Souza³

et al. 2017

Aust J Crop Sci

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Monitoring soil physical quality in areas cultivated with sugarcane has become a key management practice of this crop. It is due to the in-field traffic of heavy machines, implements, high mass harvesters and transhipments in the area have caused changes in soil structure and promoted the fall of the crop yield.. This study evaluated physical attributes of soil and the least limiting water range to assess the effects caused by wheel traffic in areas with mechanized harvest of sugarcane. The design was completely randomized in a factorial 2 x 2 x 4, which were evaluated two areas of mechanical harvesting: 1 -Six years (T 1 ); 2 -Eighteen years of cultivation (T 2 ); Two sampling sites: 1 -Canteiro; 2 -Planting line; Four layers of soil sampled (0.00 to 0.10, 0.10-0.20, 0.20-0.30 and 0.30-0.40 m) with 4 repetitions. We evaluated bulk density (BD), mechanical resistance to penetration (RP), water content in the soil (WCS), macroporosity (Ma), microporosity (Mi), total porosity (TP), water retention curve, the least limiting water range (LLWR) and soil organic carbon (SOC). We observed that the area with mechanical harvest system after three crop cycles produced a high loadbearing capacity and high SOC. The same area also demonstrated high Ma and LLWR, and low BD and RP levels in the rows. The LLWR levels were high as well in the area with one cane cycle but decreased as the number of harvest cycles increased. In the areas with one and three cycles the critical bulk density (CBD) ranged between 1.40-1.50 Mg m -3 and 1.24-1.28 Mg m -3 respectively, while the LLWR was zero (LLWR = 0) with the limiting RP between 2.0 and 3.5 Mpa. The physical attributes are changed by heavy machinery traffic in the cane fields, but the effects of these changes are minimized when several crop cycles are conducted in the same area.

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Section: The Least Limiting Water Range (Llwr)supporting

confidence: 87%

Section: The Least Limiting Water Range (Llwr)mentioning

confidence: 99%

Physical attributes and limiting water range as soil quality indicators after mechanical harvesting of sugarcane

Filho¹,

Souza²,

Souza³

et al. 2017

Aust J Crop Sci

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“…Very common in publications addressing the least limiting water range is its estimation for several soil densities or degrees of compaction, aiming to predict the effects of a possible compaction on the soil physical quality and crop yields (Imhoff et al, 2001;Leão et al, 2004;Beutler et al, 2008;Blainski et al, 2009;Kaiser et al, 2009;Petean et al, 2010;De Lima et al, 2012;Farias et al, 2013;Guimarães et al, 2013;Moreira et al, 2014a;Seben Junior et al, 2014). In this case, θ fc and θ pwp are usually estimated as a function of an empirical relationship between the water content, bulk density and matric potential proposed by Silva et al (1994) or other also empirical equations (Guimarães et al, 2013), using fixed values for the matric potential; θ pr is calculated as a function of soil bulk density using the empirical model proposed by Busscher (1990), assessing it for a fixed impedance value, commonly 2 MPa; and θ air is calculated by subtracting 0.1 m 3 m -3 from total porosity, which is a function of the bulk and particle density.…”

Section: Critical Densitymentioning

confidence: 99%

“…In this case, θ fc and θ pwp are usually estimated as a function of an empirical relationship between the water content, bulk density and matric potential proposed by Silva et al (1994) or other also empirical equations (Guimarães et al, 2013), using fixed values for the matric potential; θ pr is calculated as a function of soil bulk density using the empirical model proposed by Busscher (1990), assessing it for a fixed impedance value, commonly 2 MPa; and θ air is calculated by subtracting 0.1 m 3 m -3 from total porosity, which is a function of the bulk and particle density.…”

Section: Critical Densitymentioning

confidence: 99%

Beyond the “Least Limiting Water Range”: Rethinking Soil Physics Research in Brazil

Lier

Gubiani

2015

Rev. Bras. Ciênc. Solo

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As opposed to objective definitions in soil physics, the subjective term "soil physical quality" is increasingly found in publications in the soil physics area. A supposed indicator of soil physical quality that has been the focus of attention, especially in the Brazilian literature, is the Least Limiting Water Range (R LL ), translated in Portuguese as "Intervalo Hídrico Ótimo" or IHO. In this paper the four limiting water contents that define R LL are discussed in the light of objectively determinable soil physical properties, pointing to inconsistencies in the R LL definition and calculation. It also discusses the interpretation of R LL as an indicator of crop productivity or soil physical quality, showing its inability to consider common phenological and pedological boundary conditions. It is shown that so-called "critical densities" found by the R LL through a commonly applied calculation method are questionable. Considering the availability of robust models for agronomy, ecology, hydrology, meteorology and other related areas, the attractiveness of R LL as an indicator to Brazilian soil physicists is not related to its (never proven) effectiveness, but rather to the simplicity with which it is dealt. Determining the respective limiting contents in a simplified manner, relegating the study or concern on the actual functioning of the system to a lower priority, goes against scientific construction and systemic understanding. This study suggests a realignment of the research in soil physics in Brazil with scientific precepts, towards mechanistic soil physics, to replace the currently predominant search for empirical correlations below the state of the art of soil physics.

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“…O IHO permite quantificar os mecanismos e os processos de perda e recuperação da qualidade física do solo, em função do seu uso e manejo (Guimarães et al, 2013), e geralmente é adotado para relacionar propriedades do solo e práticas de manejo (Safadoust et al, 2014).…”

Section: Introductionunclassified

Variabilidade espacial do intervalo hídrico ótimo de solos cultivados em sistema plantio direto

Klein

Graebin

Bortolanza

et al. 2016

Pesq. agropec. bras.

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Resumo -O objetivo deste trabalho foi avaliar a acurácia das regressões que definem os limites do intervalo hídrico ótimo e a validade do uso deste indicador ao se considerar a variabilidade espacial de lavouras sob sistema plantio direto. Foram coletadas 100 amostras de solo com estrutura preservada, em áreas com dimensões de 10x10 m, em Latossolo Vermelho distrófico, Nitossolo Vermelho distroférrico e Latossolo Vermelho aluminoférrico, manejados sob sistema plantio direto. Determinaram-se porosidade de aeração (0,10 m 3 m -3 ), capacidade de campo (potencial de -0,006 MPa), ponto de murcha permanente (potencial de -1,5 MPa) e resistência mecânica do solo à penetração crítica (2 MPa). As regressões que descreveram a capacidade de campo tiveram os menores coeficientes de determinação, enquanto as que descreveram a porosidade de aeração, o ponto de murcha permanente e a resistência mecânica do solo à penetração apresentaram os maiores valores. As regressões que definem o limite da capacidade de campo não são acuradas em descrever a variação na umidade volumétrica do solo por meio da densidade do solo, e os solos avaliados apresentam elevada variabilidade espacial para o intervalo hídrico ótimo.Termos para indexação: capacidade de campo, ponto de murcha permanente, porosidade de aeração, resistência mecânica do solo à penetração. Spatial variability of the least limiting water range of soils under a no-tillage systemAbstract -The objective of this work was to evaluate the regressions that define the least limiting water range limits and the validity of using this indicator considering the spatial variability of crops under a no-tillage system. One hundred undisturbed soil samples were collected in areas with dimensions of 10x10 m, in two different Oxisols and an Ultisol managed under no-tillage. Air-filled porosity (0.10 m 3 m -3), field capacity (potential of -0.006 MPa), permanent wilting point (potential of -1.5 MPa), and soil mechanical resistance (2 MPa) were determined. The regressions that described field capacity had the lowest coefficients of determination, whereas those that described air-filled porosity, permanent wilting point, and soil mechanical resistance to penetration showed the highest values. Regression adjustments that define field capacity limits are not accurate in explaining variation on volumetric soil water content through bulk density, and the evaluated soils show high spatial variability regarding the least limiting water range.

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Intervalo hídrico ótimo para avaliação da degradação física do solo

Cited by 25 publications

References 53 publications

Physical attributes and limiting water range as soil quality indicators after mechanical harvesting of sugarcane

Physical attributes and limiting water range as soil quality indicators after mechanical harvesting of sugarcane

Beyond the “Least Limiting Water Range”: Rethinking Soil Physics Research in Brazil

Variabilidade espacial do intervalo hídrico ótimo de solos cultivados em sistema plantio direto

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