The Solimoes/Amazonas River channel high and low land floodplain soils were studied on Manacapuru, Iranduba, Itacoatiara and Silves townships, with purpose the evaluate the chemical characteristics of floodplain soils, as well as, the effect of land use system on soil nutrient status. Nineteen different systems were sampled, eight in the low Solimões river and eleven in medium Amazonas river. Sampling was performed on 0-10, 10-20 and 20-40 cm deep upper soil layers. Contents of pH, Al, Ca, Mg, K, P, C, N, Zn, Cu, Mn, and Fe, were determined. All the land use shows high available of Ca, Mg, P, Zn, Cu, Mn e Fe. Despite the majority soil samples presented high contents of K, the secondary forest and agroforestry systems presented medium content of K, demonstrated this nutrient can be deficient in some systems in the floodplain soils. The systems of forest and secondary forest presented more acidity and higher available Al, contracting with the others systems land use. C and N levels were lower confirming N to be one of the main limiting factors on the farming yield in the Amazonian floodplains.
Floodplains soils; Soil fertility; Nutrient status; System land use
