Available micronutrients in agricultural soils of Tenerife (Canary Islands). I.: copper and zinc

Abstract

A study about available Cu and Zn contents and the influence of some soil properties on the availability of these micronutrients for crops has been carried out in most of the agricultural zones of the Island of Tenerife (Canary Islands). The mean Cu content was 4.75 mg L-$ (AAAc-EDTA extractable Cu), 22.13% of soil presented values considered as marginals (1-2 mg L-$ Cu), and 6% contained levels below the value estimated as critical (1 mg L-$ Cu). Only 3.64% of analyzed soils showed high Cu values (>17 mg L-" (DTPA extractable Zn), a value sensibly higher than that reported by an international study carried out by FAO Unesco, 6.4% of the soils were within the Zn deficient range (<0.5 mg L' Zn), while 16.80% were potentially deficient in this element (0.5-1.0 mg L ' Zn). Levels considered as excessive (>10 mg L-$) appeared in 12.35% of the soils. When the study was carried outby zones (north and south), the highest Cu and Zn contents were present in the northern zone (mean values: 6.69 mg L ' Cu and 7.08 mg L-' Zn). Various correlations between some soil parameters and the studied micronutrients were observed.