Cobalt and sorbed complex of the soils of the soil Unit Utinga

Abstract

Considering the development of livestock production in the Litoral Mata area of Pernambuco and Alagoas, and the significance of mineral elements in animal nutrition, the author has studied some soils to detect cobalt as well as macroelements deficiencies. Representative "Unidade Utinga" soils from coastal Pernambuco and Alagoas were collected and analysed through spectrophotometry, flamephotometry and other methods. According to the classification referred to by Reddy and Mahte, 1961, these soils proved to be deficient in total cobalt (less than 2.5 ppm, flueridric extract), as well as in soluble cobalt (less than 0.1 ppm, CH₂COONH₄ 1 N and CH₃COOH 0,5 N extract). Of the interchangeable cations, K+, Na+, Ca²⁺ and Mg²⁺ no one was emphasized, although Ca was predominant over the others. Since manganese is non toxic (Dantas 1971) attention should be called to Al²⁺, although the causes of toxicity of acid soils are not very well established yet. According to Carr and Torekin (1961), Co has a tendency to be associated to mangnesium more than with iron (II) and so the largest part of cobalt in the granitic rocks is concentrated in the ferromagnesian minerals. The analytic e values are in Tables 1 and 2.