African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 5972

Full Length Research Paper

Effects of different soil sampling instruments on assessing soil fertility in the caatinga area, Brazil

Vinicius Mendes de Azevedo1
  • Vinicius Mendes de Azevedo1
  • 1Departamento de Agronomia, Universidade Federal Rural de Pernambuco, CEP: 52171-900, Recife, PE, Brasil.
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Duarte Barbosa3
  • Duarte Barbosa3
  • 3Departamento de Ciência Florestal, Universidade Federal Rural de Pernambuco, CEP: 52171-900, Recife, PE, Brasil
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Fernando José Freire
  • Fernando José Freire
  • 1Departamento de Agronomia, Universidade Federal Rural de Pernambuco, CEP: 52171-900, Recife, PE, Brasil.
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, Luis Carlos Marangon
  • , Luis Carlos Marangon
  • 3Departamento de Ciência Florestal, Universidade Federal Rural de Pernambuco, CEP: 52171-900, Recife, PE, Brasil
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Emídio Cantídio Almeida de Oliveira
  • Emídio Cantídio Almeida de Oliveira
  • 2Unidade Acadêmica de Serra Talhada, Universidade Federal Rural de Pernambuco, CEP: 59909-460, Serra Talhada, PE, Brasil.
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Alexandre Tavares da Rocha
  • Alexandre Tavares da Rocha
  • 2Unidade Acadêmica de Serra Talhada, Universidade Federal Rural de Pernambuco, CEP: 59909-460, Serra Talhada, PE, Brasil.
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Alexandre Campelo de Oliveira1
  • Alexandre Campelo de Oliveira1
  • 1Departamento de Agronomia, Universidade Federal Rural de Pernambuco, CEP: 52171-900, Recife, PE, Brasil.
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Marcos Ribeiro da Silva Vieira
  • Marcos Ribeiro da Silva Vieira
  • 2Unidade Acadêmica de Serra Talhada, Universidade Federal Rural de Pernambuco, CEP: 59909-460, Serra Talhada, PE, Brasil.
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  •  Accepted: 07 March 2013
  •  Published: 31 March 2013

Abstract

 

Soil sampling is designed to ensure obtaining reliable information about the existence, concentration and distribution of the analyzed substances in the investigated area. The caatinga is usually characterized as tree and shrub formations, mostly with high fertility soils, but suffering major physical limitations. This study aimed at determining the minimum number of single samples that theoretically should be used to form a composite sample representative of the depths 0 to 10, 10 to 20, and 20 to 30 for the chemical characteristics: pH, P, K+, Ca2+ and Mg2+, as well as show that the average fertility estimated from the arithmetic mean of the results of single samples did not differ statistically from that estimated from the chemical analysis of the composite sample and statistically evaluate the effects of collection instruments (auger, cut-shovel and cup-auger) at a depth of 0 to 10 in the main indices of soil fertility. The study was conducted in a ​​caatinga area near the city of Arcoverde, State of Pernambuco-PE. Samples were collected from 40 plots of 250 m2. The minimum number of simple samples that should be used to form a representative composite sample for fertility indices increases with decreasing angular error. According to the results, there was less spatial variability to the pH at all depths analyzed. Below 0.2 m, the number samples to be at maximum for proper estimations of P and K+levels in soils. A smaller number of samples can be taken for the variables, pH, Ca²+ and Mg²+. Significant differences in rates of fertility (pH, P and Mg2+) were observed among the instruments. The order of variability was different for all instruments. There were no differences in fertility rates for the average of single samples over the average of composite samples consisting of three simple subsamples.

 

Key words: Soil analysis, collection instrument, variability.