X-ray fluorescence spectrometry of some "Cerrado Soils" in Brazil
1992
Ando, T. (Hiroshima Univ., Fukuyama (Japan). Faculty of Applied Biological Science) | Washiyama, J. | Macedo, J.
More than 50 million ha of Cerrado region in Brazil is estimated to be developed as farmland. Since Cerrado soils include various soil types, a great number of soil samples should be analyzed for better land use and better soil management. In this study, 64 soil samples were analyzed by X-ray fluorecence spectrometry (XFS) and chemical analyses to estimate the elemental composition of Cerrado soils and to examine the applicability of XFS to them. Higher concentrations of exchangeable Al were found only in the soils of pH (N-KCl) lower than 4.5. The Al concentrations increased exponentially with decreasing in soil pH. The linear correlation between soil pH (X) and exchangeable Al (Y, mg/100g dry soil) was highly significant (log Y=8.430-1.983X, r=0.982, n=30) in the mineral soils. The concentrations of skeletal elements (Si, Al, Fe and Ti) were very similar through horizons in most of the Cerrado soils. However, the elemental compositions were locationspecific and did not always relate to the soil type. The analytical results indicated that the composition of skeletal elements was determined mainly by the parent materials. Although K, Ca, Mg, P, Zn and Mn tended to accumulate in the surface horizons, the variation among horizons was much smaller than that among the sampling sites. The soils in Brasilia contained generally very low amount of these nutrient reserves. High linear correlation coefficients between total and available nutrient contents of Ca, Mn, Mg and P indicated that concentrations of these available nutrients in soils could be estimated from XFS data
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