Formas de fósforo do solo em sítios de terra preta arqueológica na Amazônia Oriental.

Abstract

The vast majority of Amazonian soils are acidic. low cation exchange capacity and low fertilit\. The soil is therefore a limiting factor for productivity and sustainability of agricultural production systems. Among the nutrients, phosphorus is üie second element that most limits productivity in tropical soils. even though the total concentration of element in soil are high relative to requirements for plants. only a small fraction of this has a low binding energy which allows desorption and tlieir availability to plants. On the other hand. occur at sites of Amazonian Dark earth Archaeology (TPA). interpreted as a product of past human action. Where high fertility is found associated with the accumulation of organic material deposited in the indigenous villages in prehistoric times, sening as a tme composting deposits resulting in highly fertile soils Thus, the objective was to work with ese characterize and quantify lhe organic fonns of phosphorus requirements of TPA. as weli as to characterize the chemical properties, the soils of sites of TPA and their surrounding areas. in five sites located in the eastem Amazon. Samples were collected in profile. one within the site of TPA and one in the adjacent soil total of 10 profiles. which were analyzed horizons Al. AB. BA and B for the fractionatiou of organic phosphorus (Po) using the methodology proposedby Bowman e Cole (1978a 1978b) and Bowman (1989) and for the determination of the chemical results were processed using descriptive statistical procedures for data on fertility and also was the analysis of the data and P fractions by multivariate analysis teclmiques of principal components The results showed the prcdominance of organic P forms in surface where on average 46.4% is soluble in acid (Po H +). corresponding to 38.52% and 15.08% Pol is soluble in alkali médium (Po-OH). There was a predominance of total inorganic P (Ph) ou the organic P (Pot). but to the labde organic P was higher than inorganic P in rela liou to the chemical pH H20. MO, P. K. Ca Mg. Mn available CEC and V% these were higher in soils from the sites of TPA comparcd to its adjacent soil.