Fundamentação teórica dos sistemas de amostragem de solo de acordo com a variabilidade de características químicas.

Guarçoni, André; Álvarez, V Víctor Hugo; Sobreira, Fabricio Moreira

doi:10.28940/terra.v35i4.172

Cited by 5 publications

(9 citation statements)

References 24 publications

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“…The lower accuracy in the maps of the chemical attributes of the soil in relation to the physical ones (Figure 5) agrees with several studies about spatial variability carried out with chemical attributes of the soil using different sample sizes (from 9 to 164 samples) and sample densities (from 25x25 to 173x173), in different Brazilian states, therefore susceptible to different climates and soil types, and with other crops besides soy (corn and oats) (Cherubin et al 2014(Cherubin et al , 2015Kestring et al, 2015;Guarç oni et al, 2017). This is because the chemical attributes of the soil are more sensitive than the physical ones (therefore, than the SPR), concerning the description of spatial variability with a reduced number of samples (Jacob and Klutle, 1956).…”

Section: Analysis Of the Physical-chemical Attributes Of The Soilsupporting

confidence: 86%

Reduction of Sample Size in the Soil Physical-Chemical Attributes Using the Multivariate Effective Sample Size

Canton

Guedes

Uribe-Opazo

2021

JAS

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Financial investment with collection and laboratory analysis of soil samples is an important factor to be considered when mapping agricultural areas with soybean planting. One of the alternatives is to use the spatial autocorrelation between the sample points to reduce the number of elements sampled, thus restricting the collection of redundant information. This work aimed to reduce the sample size of this agricultural area, composed of 102 sample points, and use it to analyze the spatial dependence of soil macro- and micro- nutrients, as well as the soil penetration resistance. The agricultural area used in this study has 167.35 ha, cultivated with soybean, which the soil is Red Dystroferric Latosol, and the sampling design has used in this agricultural area is the lattice plus close pairs. The reduction of the sample size was made by the multivariate effective sample size (ESSmulti) methodology. The studies with the simulation data and the soil attributes showed an inverse relationship between the practical range and the estimated value of the univariate effective sample size. With the calculation of ESSmulti, the sample configuration was reduced to 53 points. The Overall Accuracy and Tau concordance index showed differences between the thematic maps elaborated with the original and reduced sampling designs. However, the analysis of the variance inflation factor and the standard error of the spatial dependence parameters showed efficient results with the resized sample size.

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Section: Analysis Of the Physical-chemical Attributes Of The Soilsupporting

confidence: 86%

Reduction of Sample Size in the Soil Physical-Chemical Attributes Using the Multivariate Effective Sample Size

Canton

Guedes

Uribe-Opazo

2021

JAS

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“…Tradicionalmente, a amostragem do solo é realizada adotando a divisão de glebas homogêneas de tamanho máximo preconizado por literatura, como 10 ou 20 ha (CANTARUTTI; ALVAREZ; RIBEIRO, 1999;IAC, 2020). Entretanto, a amostragem aleatória baseada na estatística "clássica" não é apropriada diante da ocorrência de dependência espacial (GUARÇONI; ALVAREZ, SOBREIRA, 2017). Nestas circunstâncias, recomendam-se técnicas geoestatísticas de interpolação para a estimativa de atributos do solo (SHAHRIARI et al, 2019;SULIEMAN;ALGARNI, 2019;LI;WAN;SHANG, 2020).…”

Section: Introductionunclassified

Dependência espacial e krigagem para a estimativa textural de solos em São João Evangelista

et al. 2022

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Investigações científicas sobre a distribuição espacial de atributos texturais de solo subsidiam o planejamento da coleta de amostras para análise granulométrica, importante para a definição de tratos culturais. O objetivo foi avaliar o desempenho de diferentes métodos de krigagem e modelos matemáticos de semivariograma teórico na estimativa textural em uma área de Latossolo Vermelho-Amarelo Distrófico. O estudo foi conduzido em uma área de 41,07ha no Instituto Federal de Educação, Ciência e Tecnologia de Minas Gerais, campus São João Evangelista. Estabeleceu-se uma grade amostral regular de 130 × 130m, totalizando 33 pontos amostrais georreferenciados. A análise de interpolação espacial adotou dois métodos de krigagem (simples e ordinária) e três modelos de semivariograma teórico (esférico, exponencial e gaussiano). A intensidade da dependência espacial das frações silte e argila tenderam a ser menores que aquela da fração areia. Para fins texturais, estimou-se o tamanho ideal de glebas circulares de 18,48ha para a obtenção de amostras compostas de solo. Conclui-se que a krigagem simples associada ao modelo de semivariograma gaussiano é eficiente para análises de interpolação espacial de frações de areia e argila. A combinação desse método de krigagem com o modelo de semivariograma esférico é preciso para a estimativa da fração silte. Palavras-chave: Areia. Silte. Argila. Geoestatística. Método probabilístico. Space dependence and kriging for soils texture estimate in São João Evangelista, Minas Gerais, Brazil Abstract Scientific investigations concerning the spatial distribution of soil textural attributes support planning of sample collection for granulometric analysis, important for definition of cultural tracts. This work aimed to evaluate the performance of different kriging methods and mathematical models of theoretical semivariogram in textural estimation of adystrophic Red Yellow Latosol. The study area has 41.07ha at the Federal Institute of Education, Science and Technology of Minas Gerais, campus São João Evangelista. A regular sampling grid of 130 × 130m was established, totaling 33 georeferenced sample points. Spatial interpolation analysis adopted two kriging methods (simple and ordinary) and three theoretical semivariogram models (spherical, exponential and Gaussian). Spatial dependence intensity of the silt and clay fractions tended to be less than that of the sand fraction. For textural purposes, the ideal size of 18.48 ha circular plots was estimated for obtaining samples of soil. It is concluded that the simple kriging associated with gaussian semivariogram model is efficient for spatial interpolation analyzes of sand and clay fractions. The combination of this kriging method with spherical semivariogram model is required for estimating the silt fraction. Keywords: Sand. Silt. Clay. Geostatistics. Probabilistic method.

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“…The chemical analysis is routinely done with composite soil sample, formed by the homogeneous mixture of several simple samples. Given the predominance of research aimed at the definition of the number of simple samples to form a composite (MACHADO et al, 2007;SANTOS et al, 2009;LIMA et al, 2010;SANTOS et al, 2013, GUARÇONI et al, 2017 it becomes relevant the dimensioning quantity of composite samples for the evaluation of soil fertility. The sample size is influenced by the purpose of sampling, precision required, method of selection and distribution of sample units, available resources and, above all, variation of the characteristic of interest (SHIVER; BORDERS, 1996).…”

Section: Introductionmentioning

confidence: 99%

“…There is a widespread thought which states that random sampling is not appropriate for determining fertility, due to spatial dependence of soil chemical attributes (GUARÇONI et al, 2017). However, it should be pointed out that the random sampling itself, based on "classical" statistics, can generate independence between sample units when made actually at random, which would justify their use (SHIVER; BORDERS, 1996;GUARÇONI et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…The random or zigzag distribution of collection points is extensively used to obtain simple soil samples. In this perspective, several surveys have contemplated the analysis of chemical attributes representativeness applying simple random sampling or geostatistical analysis (HEIM et al, 2009;LIMA et al, 2010;OLIVEIRA et al, 2014;OLIVEIRA et al, 2015, GUARÇONI et al, 2017. It is emphasized that the strata definition is a laborious task compared to the unrestricted sample units distribution, but it has great potential for sample error control (SHIVER; BORDERS, 1996).…”

Section: Introductionmentioning

confidence: 99%

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Sampling of Chemical Attributes in Forest Soils

Lafetá

Penido

Martins³

et al. 2019

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Information about sample adequacy that represents soil chemical attributes distribution are fundamental for a better rationalization of the use of correctives and fertilizers. The objective was to evaluate the variability of these attributes and to size the minimum number of composite samples to represent the fertility of forest soils. The total area planted was 9,101ha, constituted of 265 commercial eucalypt stands. The 687 soil composite samples obtained were for chemical analysis. It was evaluated the performance of two exploratory analysis techniques and six sampling procedures. The attributes P, K, Ca, Mg and S presented higher coefficient of variation (>35%). In contrast, the distributions of Al, organic matter and, mainly, pH were the most homogeneous. The sample error was smaller as the amount of composite samples increased. The representative of all chemical attributes (sample error of 5%) was achieved with a minimum of 309 (one each 29ha, 1:29) and 295 (1:31) composite samples from sampling procedures simple casual and stratified by altitude class, respectively. Both procedures were promising for soil sampling, especially, when applying the boxplot for identification and removal of outliers. ResumoAmostragem de atributos químicos em solos florestais. Informações sobre a suficiência amostral que represente a distribuição de atributos químicos do solo são fundamentais para melhor racionalização do uso de corretivos e fertilizantes. O objetivo foi avaliar a variabilidade desses atributos e dimensionar o número mínimo de amostras compostas para representar a fertilidade de solos florestais. A área total de plantio foi de 9.101ha, constituída por 265 talhões comerciais de eucalipto. Foram obtidas 687 amostras compostas de solo para a análise química. Avaliou-se o desempenho de duas técnicas de análise exploratória e seis procedimentos de amostragem. Os atributos P, K, Ca, Mg e S apresentaram maior coeficiente de variação (>35%). Em contrapartida, as distribuições do Al, matéria orgânica e, principalmente, pH foram as mais homogêneas. O erro amostral foi menor à medida que aumentou a quantidade de amostras compostas. A representatividade de todos os atributos químicos (erro amostral de 5%) foi alcançada com o mínimo de 309 (uma a cada 29ha, 1:29) e 295 (1:31) amostras compostas para os procedimentos de amostragem casual simples e estratificada por classe de altitude, respectivamente. Ambos os procedimentos se mostraram promissores para a amostragem de solo, especialmente, quando se aplicou o boxplot para identificação e remoção de outliers. Palavras-chave: Boxplot; estratificação; tamanho da amostra.

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Fundamentação teórica dos sistemas de amostragem de solo de acordo com a variabilidade de características químicas.

Cited by 5 publications

References 24 publications

Reduction of Sample Size in the Soil Physical-Chemical Attributes Using the Multivariate Effective Sample Size

Reduction of Sample Size in the Soil Physical-Chemical Attributes Using the Multivariate Effective Sample Size

Dependência espacial e krigagem para a estimativa textural de solos em São João Evangelista

Sampling of Chemical Attributes in Forest Soils

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