Pore network of an Inceptisol under different uses and relativized S-index as an indicator of soil physical quality

Júnior, Raimundo Nonato de Assis; Mota, Jaedson Claúdio Anunciato; Freire, Alcione Guimarães; Alencar, Thiago Leite de

doi:10.1590/s0100-204x2016000900057

Cited by 5 publications

(6 citation statements)

References 20 publications

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“…In this context, we have attempted to identify, select, and assign quantitative values for the best quality indicators of the performance of certain soil functions. Among several indicators, Assis Júnior et al (2016) presented an assessment index for soil structure (S relative ), which derived from the S index proposed by Dexter (2004).…”

Section: Introductionmentioning

confidence: 99%

“…The relativized S index (S relative ) allows inferring quantitatively about the effects of different uses and management on the soil structure. Among the advantages of the aforementioned indicator, it is worth noting the lack of ranges of indicative values of soil quality as in the S index (ASSIS JÚNIOR et al, 2016). According to Silva et al (2010) and Jong van Lier (2014), the limits used in the S index are provisional and are not valid for several conditions described in the literature.…”

Section: Introductionmentioning

confidence: 99%

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Response Function for the Srelative Index in Cambisol Treated With and Without Bovine Liquid Biofertilizer

et al. 2018

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The present study aimed at assessing the influence of physical properties associated with soil structure on the S relative index. Two soil conditions under Ficus carica L. cultivation were studied (with or without liquid bovine biofertilizer in the irrigation water), in the 0-0.1 m and 0-0.3 m layers. Disturbed and undisturbed soil samples were collected from the above-mentioned layers and physical analyzes, pertinent to the study objective, were performed. The response function model was applied to verify how the soil independent physical variables influence on the S relative index in the 0-0.1 m and 0-0.3 m layers, with 0 and 60% biofertilizer, being combined two to two. Once the response functions were known, the slopes of both functions were compared, being represented by the coefficients β11-β12 and β21-β22. This comparison enabled verifying whether there was an effect of the treatments on the response variable. In addition, the standard error of the difference between coefficients was calculated, and the Student's t-test applied. The method of multiple regression was also used to confirm the effect of the variables on the S relative index for the 0-0.3 m layer in both treatments. Then, the variables with greater weight were selected by a backward elimination method to estimate the S relative . The results showed that the S relative index is strongly influenced by properties of the porous fraction, with total porosity and continuity of pores being of significant influence. Management with liquid bovine biofertilizer results in improvement in the soil structure, with effects measured by the S relative index.Keywords: S index. Soil structure. Organic matter. FUNÇÃO DE RESPOSTA PARA O ÍNDICE S RELATIVO EM CAMBISSOLO TRATADO COM E SEM BIOFERTILIZANTE LÍQUIDO BOVINORESUMO -Objetivou-se com esta pesquisa estudar a influência de atributos físicos associados à estrutura do solo no índice S relativo . Foram contempladas duas situações de solo (sob cultivo de Ficus carica L., sem aplicação e com aplicação de biofertilizante bovino líquido na lâmina de irrigação), nas camadas de 0-0,1 m e 0 -0,3 m. Foram coletadas amostras de solo com estrutura preservada e não preservada nas camadas supracitadas e realizadas análises físicas pertinentes ao objetivo do estudo. Foi aplicado o modelo de função de resposta para verificar como as variáveis físicas do solo independentes influenciam no S relativo , nas camadas de 0-0,1 m e 0-0,3 m tratadas com 0 e 60 % do biofertilizante combinadas duas a duas. Conhecidas as funções de resposta compararam-se as inclinações de ambas as funções, representadas pelos coeficientes β 1 1-β 1 2 e β 2 1-β 2 2, para verificar se houve efeito dos tratamentos na variável resposta. Além disso, calculou-se o erro padrão da diferença entre os coeficientes e aplicou-se o teste t de Student. Também foi aplicado o método de regressão múltipla para verificar o efeito das variáveis sobre o S relativo para a camada de 0-0,3 m em ambos os tratamentos. Em seguida, por meio do método backward elimination foram sel...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Response Function for the Srelative Index in Cambisol Treated With and Without Bovine Liquid Biofertilizer

et al. 2018

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“…Conceptually, this index represents the slope of the line tangent to the inflection point of the SWRC. Several studies, such as Dexter (2004 a, b, c), Assis Júnior et al (2016), Magalhães et al (2018), Rossetti & Centurion (2018), have confirmed the accuracy of the S index using the soil compaction state, which is correlated with the microstructural porosity, bulk density, and soil organic matter content.…”

Section: Introductionmentioning

confidence: 89%

Pedotransfer Function to Estimate the Soil Structural “S” Index and Spatial Variability in an Oxisol Within a Livestock Farming System

et al. 2020

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Various attributes are often required to build soil quality indicators. However, determining these attributes is time-consuming and requires several specific devices. Thus, it is desirable to develop indexes that express soil quality based on easily determined attributes. The objective of this study was to investigate the spatial variability of the S index and its correlation with other physical and chemical soil attributes to generate a pedotransfer function for estimating the S index. A georeferenced sampling mesh covering 1.4 ha and employing 71 points was installed. The soil samples were collected in 0.00-0.15 m and 0.15-0.30 m deep layers to determine the physical and chemical attributes. The results indicated that the S index was correlated with porosity, carbon stocks, cation exchange capacity, and particle size fractions. However, macroporosity, microporosity, and sand content were the most suitable attributes for the construction of pedotransfer functions. A principal component analysis indicated that the S index was representative of 9.4% and 11.5% of the total variability in the dataset in the respective soil layers. Spherical semivariogram models showed that the S index was spatially dependent and ranged between 84-188 m. The S index maps estimated by the pedotransfer function resemble the observed S values; therefore, the function can be applied in spatial variability studies.

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“…As to the refinement of the S relative -index, the objective was to obtain a reference S-index value from the water retention curve determined using soil with disturbed structure as close as possible to the textural porosity, since the perception of the studies of Freire (2012), Alves (2013), and Assis Júnior et al (2016) is that the curve determined from the ADFE still contains part of its porosity associated with the microstructure. In the refinement process, the S relative -index was obtained according to the same procedure for the arrangement of the soil in the rings.…”

Section: Laboratory Analysesmentioning

confidence: 99%

“…Among the various indicators, an index of evaluation of soil structure-S relative -index-derived from the S-index proposed by Dexter in 2004, was presented by Freire (2012). The results observed so far have been promising; however, it was verified in Freire (2012), Alves (2013), and Assis Júnior et al (2016) the incomplete individualization of the particles to obtain the soil water retention curve reference. Thus, the S relative -index requires refinement to improve its sensitivity to physical changes imposed to the soil.…”

Section: Introductionmentioning

confidence: 98%

Soil Physical Quality Indicators and Refinement of the Evaluation Method through the Srelative

Alencar¹,

Chaves²,

Freire³

et al. 2018

JAS

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This study aimed to verify the efficiency of indicators of measure of physical attributes' alterations and to refine the S relative determination method in order to increase its sensitivity to soil physical alterations. Soils under Ficus carica L. cultivation (with 0, 20, 40 and 60% of liquid bovine biofertilizer in the irrigation depth) and under forest were used. Parameters evaluated included soil granulometry, soil bulk and particle density, soil water retention curve (SWRC), porosity and the indices S and S relative . The experimental design was completely randomized with four replicates. For S relative refinement, with the SWRC containing only textural porosity, the soil was dispersed in water and with the addition of 1 N sodium hydroxide (with and without removal of sodium through washing). An ANOVA was performed for 0, 20, 40 and 60% of biofertilizer in 0-10, 10-20 and 20-30 layers; Dunnett test was used to compare the mean values of S-index and S relative -index. With respect to four methods to obtain the S relative -index the means were compared by Tukey test. Tests of line parallelism and intercept were performed for the regressions between each of the soil physical variables and S relative -index obtained. It was found that S and S relative indices were sensitive to soil physical alterations caused by the application of the biofertilizer; Srelative-index was sensitive to variation in soil bulk density and total porosity and the S relative -index obtained from the method of soil dispersion in water is more sensitive to soil physical alterations in comparison to S relative -index obtained through ADFE.

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Pore network of an Inceptisol under different uses and relativized S-index as an indicator of soil physical quality

Cited by 5 publications

References 20 publications

Response Function for the Srelative Index in Cambisol Treated With and Without Bovine Liquid Biofertilizer

Response Function for the Srelative Index in Cambisol Treated With and Without Bovine Liquid Biofertilizer

Pedotransfer Function to Estimate the Soil Structural “S” Index and Spatial Variability in an Oxisol Within a Livestock Farming System

Soil Physical Quality Indicators and Refinement of the Evaluation Method through the Srelative

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