CHARACTERIZATION OF PHYSICAL AND CHEMICAL -PROPERTIES OF LOWLAND SOILS OF SOME STATES OF BRAZIL

Lowland (''varzea'') soils in Brazil have potential to support agricul tural production, but very little is known about their fertility. The presente study was undertaken to characterize the chemical and physica l properties of representative lowland soils collected at 0-20, 20-40, 40-60, and 60-80 cm depth intervals from 18 sites in the states of Pa rana, Minas Gerais, Rio Grande do Norte, Piaui, and Maranhao, Brazil. Organic matter contents averaged 3,4% in the 20 cm layer of soil. Soil pH increased with depth from a mean value of 5.6 in the surface 20 cm of soil to a mean value of 6.9 in the 60-80 cm depth interval. Severa l soils had exchangeable Al value > 1 cmol kg-1 Al, but soil Al satura tion was generally less than 60%, level frequently associated with Al toxicity. Although base saturation was fairly low in some soils, excha ngeable Ca and Mg levels were, in general, adequate throughout the pro file. Extractable P, K, Zn and Cu levels were adequate inmost surface soil samples, but Fe content was quite high in most of the samples ana lyzed. High percentage of soils in the study showed heavy texture.