Manganese and exchangeable cations of the Utinga soil Unit

Abstract

The studies on macro and microelement and on their availability are rarely developed enough to characterize the Northeastern soils. On surveying the soils of Pernambuco and Alagoas, "Unidade Utinga" drew our attention for its wide distribution and agricultural utilization. These soils, near the coast, belong to the physiographic area called "Litoral Mata". They are used agriculturally, through the production of sugar cane and subsistance crops; livestock production, at first just a monetary complement, now is increasing in importance to characterize these soils through their mineral availability to plants, representative profiles from the Litoral Mata zone of Pernambuco and Alagoas were selected. Exchangeable cations (macro-elements) were extracted by percolation with normal solution of ammonium acetate, pH = 7 e manganese was submitted to several extracters: 1 N ammonium acetate, pH = 7; 0,5 N acetic acid; concentrated flueridric acid and 0,05% alcoolic hydroquinene solution. The cation exchange capacity of these soils is low, and their available manganese is so surprisingly insignificant, that it was not even detected by employed method of analysis, as shown in Tables 1 and 2. Horowitz and Dantas (1966) suggested that low yields of fertilized and irrigated soils in the Litoral Mata zune of Pernambuco must, at least partially, be attributed to the deficiency of manganese and related minor elements (As, Co, Mo, Ni, V and Zn) which are deficient in the sedimentary rocks.