Quality of soil organic matter in relation to the pedogenesis of some cambisols at Irecê, Bahia, Brazil
01/Dec/1998
Six calcareous soil profiles (P1, P2, P3, P4, P5 and P6) were investigated with regard to their main characteristics of soil organic matter related to structural organization. The effect of degrading processes on these soils was also considered, mainly under intensive cultivation. Based on morphological in situ observation and analytical data, the profiles P1 e P2 showed organic matter with an advanced level of evolution presenting reasonable amounts of low polymerized materials (fulvic acids). Conversely, profiles P3, P4, P5 e […]
Geochemical balance of soils derived from basic-ultrabasic rocks under the subtropical climate of Rio Grande do Sul state, southern Brazil
01/Dec/1997
The mass balance of weathering of soils derived from basic-ultrabasic rocks under the subtropical climate of southern Brazil, the least weathered soils found to date in the Rio Grande do Sul state, showed a higher relative concentration of the mobile elements in the surface horizons than in the subsurface horizons. These features, associated to the soil mineralogy and morphology, indicate the occurrence of erosive-depositional events in a pedogenetically recent past as well as a main contribution from less weathered materials […]
Spatial variability of soil characteristics in the Planalto Médio region, state of Rio Grande do Sul, Brazil: I. nested analysis of variance
01/Sep/1997
The spatial variability of the soil characteristics colour, clay content, pH and penetrometer resistance was evaluated in seven areas on which strongly weathered and intensively cropped soils occur, in the Planalto Médio region, State of Rio Grande do Sul, Brazil. Nested analysis of variance was performed with the objective of assessing their homogeneity and optimal soil sampling density. Representative soil profiles were characterized and classified in these areas. Field work was performed from August to November, 1989. Kandiudox, Hapludox and […]
Spatial variability of soil characteristics in the Planalto Médio region, state of Rio Grande do Sul, Brazil: II. analysis of semivariance and analysis of variance
01/Sep/1997
The spatial variability of soil characteristics in the Planalto Médio region, State of Rio Grande do Sul, Brazil, was studied in six areas cultivated with soybean. Semivariance and variance analyses were applied to the data obtained by systematic soil sampling to confirm and detail results obtained by nested analysis of variance, and to estimate the variance of characteristics within soil mapping units and the range of its application for land evaluation. Field work was performed from December, 1989 to March, […]