Many extracting procedures for the plant-available zinc have been developed. Total soil Zn fractionation has been used as an attempt to understand the reactions of this nutrient in soils and the behaviour of the extracting procedures. This work evaluated the influence of soil characteristics on the concentration of Zn extracted by different procedures and on soil Zn fractions. Samples were collected from the 0-20 cm surface layer of twelve soils, representing the great soil groups of Dark-Red Latosol (LE), Red-Yellow […]

Different soil boron fractions were evaluated from 29 superficial (0-20 cm) soil samples in Ceará, Brazil. Relationships were established between soil fractions and soil properties and soluble boron, which has been used as an index of boron availability to the plants. Fractional boron analyses of the soils were carried out following a sequential procedure. The following determinations were carried out: the water soluble boron (B-Sol), the not specifically adsorbed boron (B-NEsAd), the boron associated to manganese oxide (B-OxMn), the boron […]

The effects of applying micronutrients, cattle manure, lime and splitting application of NPK fertilizers on the yield and the incidence of witches’ broom disease of cacao caused by Crinipellis perniciosa were determined in two experiments carried out on structured Terra Roxa soil (TR) and Yellow Latosol (LA), in Pará State, from 1988 to 1993, after the slash and burn of the forest. The hybrid (Sca 6 x Be 10) cacao crop was introduced utilizing banana (Musa spp.), as temporary shading, […]