Brazilian Central Plateau Research Articles

Effect of Parent Rocks on Chemical and Mineralogical Properties of Some Oxisols in Brazil

AbstractA toposequence of soils developed primarily from basalt in the Central Plateau of Brazil and a pedon developed primarily from itabirite (a hematite‐quartz metamorphic rock) were studied in the Quadrilatero Ferrifero. The itabirite‐derived Oxisol consists almost entirely—900 to 950 g kg−1 (90‐95%)—of Fe oxides and oxyhydroxides, compared with 250 to 300 g kg−1 in the basalt‐derived Oxisol. The soil on itabirite also has coarser particle size, higher particle density, and somewhat lower surface area. It lacks kaolinite and gibbsite but contains more goethite and has greater magnetic susceptibility. It also is much lower in all essential plant nutrients (except Fe and P), and much lower in several non‐nutrient minor elements as well. Magnetite grains in basalt are relatively abundant in minor elements which could be released slowly during mineral weathering. The effect of the parent material is still evident even in highly weathered soils, indicating the need for the separation between itabirite‐ and basalt‐derived Oxisols in a system of soil classification. In itabirite‐derived soils the Fe2O3/TiO2 ratio (H2SO4 digestion) is >16 and the magnetic susceptibility of the whole soil is > 189 × 10−6 m3 kg−1 (15 000 × 10−6 cgs). These limits of soil properties reflect the original parent material and could be the differentiating characteristics in soil classification systems. Particle density, amount of trace elements, and capacity to fix phosphorus are accessory properties associated with the differentiating characteristics.

The evaluation under grazing of legumes associated with Andropogon gayanus in a tropical savannah environment on the central plateau of Brazil

SUMMARYThe persistence and productivity under grazing of seven accessions of Stylosanthes macrocephala, Zornia latifolia and Zornia brasiliensis in combination with Andropogon gayanus (cv. Planaltina) were investigated in small plots at two stocking rates on a low fertility, acid oxisol in the tropical savannah of the centre-west region of Brazil.Two new accessions of S. macrocephala CIAT 2039 (CPAC 1033) and CIAT 2053 (CPAC 1034) were more productive and persistent than the control cultivar Pioneiro. After 4 years there were no differences in dry-matter yield between the two accessions. No anthracnose (Colletotrichum gloeosporioides) problems were noted in these accessions. Animals refused to graze Z. brasiliensis accessions at any time during the trial. Stocking rate effects became pronounced over time and legume contents were highest in the treatment grazed at 3·0 animals/ha. The advantages of the small-plot grazing method used in the experiment are discussed.

Revision of Glaziovianthus (Compositae: Vernonieae)

Glaziovianthus is a showy and unique Brazilian endemic of southcentral Goias and includes only two species, G. curumbensis and G. speciosus, both new combinations. Glaziovianthus is remarkable within Vernonieae for its distinctive rose-red corollas with a band of yellow at the base of the lobes; most Vernonieae evince a reddish purple corolla color. Members of this genus are readily recognizable in the field because of the large solitary red and yellow glomerule ter- minating a long (to 60 cm) peduncle. Glaziovianthus is further characterized by primitive Vernonia type-A pollen with very short colpi and a subechinate surface and by large cylindrical achenes with sulcate sericeous surfaces, prominent carpopodia, and a biseriate deciduous paleaceous pappus. Glaziovianthus (Compositae: Vernonieae) has two suffrutescent species, both of which are re- stricted to the arid Central Plateau of Brazil (fig. 1). One species is confined to campo rupestre (a special form of cerrado, Eiten 1978 and 1983) at 1000-1400 m throughout the mountains of southcentral Goias, and the other is limited to cerrado at 700-1200 m in these mountain ranges and westward into Mato Grosso. Both species are locally abundant within their respective

Toposequence of Oxisols from the Central Plateau of Brazil

AbstractLandscape position is a critical factor influencing many co‐varying soil properties even in highly weathered soils that tend to have a high degree of homogeneity. The objective of this study was to learn how the position of a soil in a toposequence influences soil color, mineralogy, and some chemical and physical properties.In a toposequence of Oxisols developed from basalt in the Central Plateau of Brazil (Goias State), moist soil color changed from dark reddish brown (2.5YR 3/4) in upper slope positions to dark yellowish brown (10YR 4/4) in lower slope positions and the following trends were observed: hematite content decreased and goethite content increased, the amount of Al substitution in the goethite structure increased, gibbsite content decreased and kaolinite content increased, and magnetic suceptibility and maghemite content of fine clay decreased. Also, the yellower soils down slope adsorbed more P and desorbed less P than the redder soils upslope, possibly because the yellower soils contain more goethite, which was found to have a smaller crystallite size and more DCB‐extractable Al than hematite. Soil color is a reliable indicator of iron oxide mineralogy which reflects the genesis of the soil and influences properties that affect plant growth. Thus, color should be used at a relatively high categorical level in soil classification systems to define classes of Latosols and Oxisols.

Six New Species of Eremanthus (Compositae: Vernonieae) from Brazil

Six new Brazilian species are described and illustrated. Eremanthus argenteus, E. auriculatus, and E. uniflorus are restricted to the Chapada dos Veadeiros of central Goias. Eremanthus seidelii is endemic to the cerrado surrounding Furnas reservoir in southwestern Minas Gerais, and E. graciellae is limited to the Serra Geral mountain range separating Goias and Bahia. Eremanthus rondoniensis is closely related to E. mattogrossensis and represents a western extension (into Rond6nia) of the glomerulatus-goyazensis-mattogrossensis complex. Eremanthus Less. has traditionally comprised an amalgam of Brazilian herbs, shrubs, and trees that exhibit the combined traits of syncephaly (secondary aggregation of heads into a glomerule), pluriseriate phyllaries, and achenes with a persistent pappus. Syncephalous heads are characteristic of Lychnophorinae, which is currently considered to be an artificial assemblage (Jones 1978). Historically, Albertinia Sprengel, Chresta Vell. Conc., Glaziovianthus G. Barroso, Pithecoseris DC., Prestelia Schultz-Bip., Pycnocephalum DC., Sphaerophora Schultz-Bip., Stachyanthus DC., and Vanillosmopsis Schultz-Bip. have been placed in synonymy with or adjacent to Eremanthus. These genera are restricted to arid portions of southern Brazil and have not been comprehensively evaluated since Baker's (1873) treatment of Compositae in Martius's Flora Brasiliensis. Eremanthus and related genera are currently under monographic revision at the University of Georgia by the senior author. During the course of several collecting trips through the Central Brazil Plateau, six previously undescribed species were discovered by the authors. The junior author's expedition followed the northern portion of Gardner's route (for details see Gardner 1846 and Schumacher 1982) through the mountainous portions of Brazil. Of particular interest is his rediscovery of limited populations of Vanillosmopsis arborea (Gardner) Baker in C. Martius in the Chapada do Araripe of southern Ceara, which had previously been known only from the type collection. Much of the Central Plateau of Brazil remains botanically unknown, and, undoubtedly, further explorations into these arid regions will yield not only range extensions for many of the following species but also additional taxa new

Floristic Composition and Community Structure in an Area of Cerrado in SE Brazil

Summary Cerrado is the generic name for the savanna-like vegetation which occupies the vast area of the central Brazilian plateau and also extends into peripheral, fragmented islands within the Surrounding moist forests. Cerrado occurs as a complex of intergrading structural sub-types which range from more or less closed forest to open grassland with scattercd shrubs, and it also shows phytogeographical shifts in floristic composition although these are as yet poorly studied. This investigation presents for the first time a full list of the woody species from one of the peripheral islands of cerrado in Sao Paulo state. In addition, a principal components analysis of the data from 60 quadrats of 10 × 25 m indicates that the two community subtypes present in this area, cerrado and campo cerrado, distinguished by Goodland on the basis of physiognomic characteristics, can also be defined in terms of species composition. The possible causes for these floristic and physiognomic sub-communities are examined but no single controlling factor can be established.

Antônio Francisco Lisboa, ‘O Aleijadinho’: An Annotated Bibliography

The state of minas gerais, atop the central brazilian plateau, has long cast a spell over people of adventurous spirit. For years it supplied the Portuguese empire with a seemingly endless supply of mineral wealth. In 1698, gold was discovered and the famous ‘century of gold’ was ushered in. The mines of Minas proved to be among the richest ever worked by man and they provided the base for the luxurious Mineiro society that flourished throughout the eighteenth century.

The Canela Since Nimuendaju: A Preliminary Report on Cultural Change

Between 1929 and 1936, the German-born Brazilian anthropologist Curt Nimuendaju spent fourteen months with the Canela Indians, otherwise known as the R4mkBkamekra, a Je-speaking people on the northeastern edge of the Brazilian central plateau. A result of his studies made during six visits is the posthumously published monograph The Eastern Timbira (1946), translated from the German and edited by the late Robert Lowie. One object of my field research among these same people has been to compare the Canela R4mk6kamekra society of today with the Nimuendaju study completed twentyfive years ago in an attempt to trace the changes that have occurred in most areas of culture, using the monograph as a base line.

Quartz crystal deposits in the state of Goiaz, Brazil

The three major quartz crystal producing regions in the state of Goiaz are on the central Brazilian plateau. Quartz crystal of commercial quality occurs as a minor constituent of quartz veins cutting Algonkian quartzites and Archean schists. Important production has been won from secondary deposits formed by weathering and erosion of the vein outcrops. Large inferred reserves of quartz crystal exist in north central and east central Goiaz.

Mountain Settlement in the Central Brazilian Plateau

Mountain Settlement in the Central Brazilian Plateau

Occurrence of facetted pebbles on the central plateau of Brazil

Occurrence of facetted pebbles on the central plateau of Brazil