Dependência espacial de atributos do solo obtidos por meio de semivariogramas e autocorrelogramas
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Data
2002-04
Autores
Rabah, Fátima Ahmad [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O presente trabalho teve por objetivo mensurar e comparar os alcances de dependência espacial de atributos do solo, obtidos por meio dos processos do semivariograma e do autocorrelograma, em uma área localizada no município de Brotas, na região central do Estado de São Paulo, com a finalidade de obter parâmetros indicativos de variabilidade espacial para utilização em futuros estudos de fertilidade do solo e correções, em mapeamentos de atributos e recomendações de manejo. As variáveis estudadas foram pH, Capacidade de Troca de Cátions (CTC), Índice de Saturação por Bases (V%), Matéria Orgânica (MO), Areia, Argila e Densidade do solo. Utilizaram-se dados de 46 pontos (sendo 18 trincheiras e 28 tradagens), de onde foram coletadas amostras em duas profundidades: 0 – 20 cm (I – horizonte superficial) e 60 – 80 cm (II – horizonte subsuperficial). Foi efetuada a análise descritiva inicial, assim como a análise da dependência espacial, relatada pelos semivariogramas e pelos autocorrelogramas. Pelos resultados obtidos pode-se concluir que: variogramas e correlogramas foram ferramentas eficientes na análise espacial e na obtenção das dependências espaciais dos atributos dos solos; os correlogramas apresentaram alcances bem menores do que os encontrados nos variogramas; pela literatura analisada há indicação que mais trabalhos utilizando-se métodos de maior teor analítico devem ser efetuados antes que qualquer interpretação possa ser adotada com maior nível de confiabilidade proporcionando mais parâmetros para comparação.
The objective of this work was to measure and compare the reaches of spatial dependency of soil attributes, obtained by means of the processes of semivariogram and autocorrelogram, in an area located in the Brotas city, in the Sao Paulo State central region, with the purpose of obtaining variability indicative parameters for use in future studies of soil fertility and its correction, mappings of attributes and management recommendations. The variables studied were pH, Capacity of Cations Exchange (CTC), Bases Saturation Index (V%), Organic Matter (MO), Sand, Clay and Bulk Density. Data from 46 points were used (being 18 trenches and 28 tradagens), from where samples were collected in two depths: 0 - 20 cm (I - superficial horizon) and 60 - 80 cm (II - subsurface horizon). The initial descriptive analysis was made, as well as the analysis of spatial dependency, reported by the semivariograms and the autocorrelograms. By the obtained results we can conclude that: variograms and correlograms were efficient tools in the spatial analyze and in the obtained spatial dependencies of the soil attributes; the correlograms presented lesser reach than the ones found in the variograms; by the analyzed literature there is indication that many works using methods of a bigger analytical proportion may be achieved before any interpretation could be adopted with higher level of reliance providing more parameters for comparison.
The objective of this work was to measure and compare the reaches of spatial dependency of soil attributes, obtained by means of the processes of semivariogram and autocorrelogram, in an area located in the Brotas city, in the Sao Paulo State central region, with the purpose of obtaining variability indicative parameters for use in future studies of soil fertility and its correction, mappings of attributes and management recommendations. The variables studied were pH, Capacity of Cations Exchange (CTC), Bases Saturation Index (V%), Organic Matter (MO), Sand, Clay and Bulk Density. Data from 46 points were used (being 18 trenches and 28 tradagens), from where samples were collected in two depths: 0 - 20 cm (I - superficial horizon) and 60 - 80 cm (II - subsurface horizon). The initial descriptive analysis was made, as well as the analysis of spatial dependency, reported by the semivariograms and the autocorrelograms. By the obtained results we can conclude that: variograms and correlograms were efficient tools in the spatial analyze and in the obtained spatial dependencies of the soil attributes; the correlograms presented lesser reach than the ones found in the variograms; by the analyzed literature there is indication that many works using methods of a bigger analytical proportion may be achieved before any interpretation could be adopted with higher level of reliance providing more parameters for comparison.
Descrição
Palavras-chave
Agronomia, Geoestatística
Como citar
RABAH, Fátima Ahmad. Dependência espacial de atributos do solo obtidos por meio de semivariogramas e autocorrelogramas. 2002. xiv, 90 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2002.