Crescimento e produção de milho associados com o intervalo hídrico ótimo

Gubiani, Paulo Ivonir; Goulart, Rafael Ziani; Reichert, José Miguel; Reinert, Dalvan José

doi:10.1590/s0100-06832013000600007

Cited by 22 publications

(25 citation statements)

References 26 publications

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“…Those who do show low correlation, as found in a wide literature review (Gubiani et al, 2013a), as well as in an experimental corroboration with eight maize crop cycles (Gubiani et al, 2013b).…”

Section: The Limiting Water Contents Their Coherence and Parametrizamentioning

confidence: 77%

“…For θ fc a water content is used that corresponds to a given matric potential (-10 or -33 kPa, in general); θ air is chosen to match the air content of 0.10 m 3 m -3 ; θ pwp is considered to correspond to the matric potential of -1,500 kPa; and θ pr is chosen equivalent to the water content at which the soil has a predefined resistance to penetration (often 2 MPa). Except in some studies (Klein and Camara, 2007;Kaiser et al, 2009;Gubiani et al, 2013b), the values in general are not tested and compared with biological measurements, and a sensitivity analysis of the outcomes of studies regarding these values is rarely performed. In some cases, only the effect of the value chosen for penetration resistance in θ pr is assessed (Betioli Júnior et al, 2012;Moreira et al, 2014b).…”

Section: The Limiting Water Contents Their Coherence and Parametrizamentioning

confidence: 99%

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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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Section: The Limiting Water Contents Their Coherence and Parametrizamentioning

confidence: 77%

Section: The Limiting Water Contents Their Coherence and Parametrizamentioning

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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“…No entanto, quando ocorrem, ao mesmo tempo, IHOs iguais a zero e amplos em uma área aparentemente uniforme, com dimensões reduzidas, como as de 10x10 m, no caso dos três solos avaliados (Figura 5), a função e a viabilidade de uso desse indicador fica comprometida. Especialmente no solo N 520 , houve grande variação no IHO no espaço amostral, em um Diversos trabalhos apontam para níveis de produtividade não condizentes com o IHO (Klein & Camara, 2007;Gubiani et al, 2013a;Cecagno et al, 2016). Diante disso, a não ocorrência de correlação entre a produtividade de culturas e o IHO pode estar relacionada ao fato de as áreas apresentarem extremos de IHO, em razão da variabilidade espacial do solo (Figura 5).…”

Section: Classe De Solounclassified

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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“…Recently, De Jong van Lier and Gubiani (2015) suggested rethinking its use in Brazil in soil physics research due, mainly, to the very few research that relates to crop production, although there are studies that show (Kaiser et al, 2009;Magalhães et al, 2009) and others question (Gubiani et al, 2013) its effectiveness.…”

Section: Monitoring Of the Soil Water Content According To The Llwr Cmentioning

confidence: 99%

Sweet Sorghum Performance Affected by Soil Compaction and Sowing Time as a Second Crop in the Brazilian Cerrado

Júnnyor

Severiano

Silva

et al. 2015

Rev. Bras. Ciênc. Solo

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Increasing attention has recently been given to sweet sorghum as a renewable raw material for ethanol production, mainly because its cultivation can be fully mechanized. However, the intensive use of agricultural machinery causes soil structural degradation, especially when performed under inadequate conditions of soil moisture. The aims of this study were to evaluate the physical quality of aLatossolo Vermelho Distroférrico (Oxisol) under compaction and its components on sweet sorghum yield forsecond cropsowing in the Brazilian Cerrado (Brazilian tropical savanna). The experiment was conducted in a randomized block design, in a split plot arrangement, with four replications. Five levels of soil compaction were tested from the passing of a tractor at the following traffic intensities: 0 (absence of additional compaction), 1, 2, 7, and 15 passes over the same spot. The subplots consisted of three different sowing times of sweet sorghum during the off-season of 2013 (20/01, 17/02, and 16/03). Soil physical quality was measured through the least limiting water range (LLWR) and soil water limitation; crop yield and technological parameters were also measured. Monitoring of soil water contents indicated a reduction in the frequency of water content in the soil within the limits of the LLWR (Fwithin) as agricultural traffic increased (T0 = T1 = T2>T7>T15), and crop yield is directly associated with soil water content. The crop sown in January had higher industrial quality; however, there was stalk yield reduction when bulk density was greater than 1.26 Mg m-3, with a maximum yield of 50 Mg ha-1 in this sowing time. Cultivation of sweet sorghum as a second crop is a promising alternative, but care should be taken in cultivation under conditions of pronounced climatic risks, due to low stalk yield.

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Crescimento e produção de milho associados com o intervalo hídrico ótimo

Cited by 22 publications

References 26 publications

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

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

Sweet Sorghum Performance Affected by Soil Compaction and Sowing Time as a Second Crop in the Brazilian Cerrado

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