O manejo das caiçaras indígenas e seus efeitos sobre as características químicas e físicas dos solos do lavrado de Roraima

Abstract

This study was divided into 3 parts. At first, we tried to point out the historical aspects of the introduction and management of cattle in the indigenous community Aningal. The second objective was to evaluate the influence of management practices of Caiçaras on the chemical characteristics of the soil and the third objective was to evaluate the influence of the same practices on soil physical properties. Livestock farming was introduced in the region of Lavrado there are at least three centuries, through the Portuguese colonization, reaching areas previously inhabited by natives of various tribes. The natives were labor on farms, where they learned of the activities associated with farming and agriculture in a soil naturally poor in nutrients, using cattle manure as fertilizer and creating calls Caiçaras. We selected three retiros (Saúba, Rebolada and Aningal) 3 systems use: Caiçara (where cattle are confined during the rainy season), Plantio (area that receives manure from Caiçara runoff) and Lavrado (control). Each retiros was individually analyzed in a randomized block design, due to differences in time use and textural classes of soils. Each area was divided into three portions, which were collected from soil samples at 0-10, 10-20 and 20-30 cm, and undisturbed, at 0-5 and 5- 10 cm. In the laboratory analyzes were conducted to determine pH, Ca, Mg, K, P, Al, Fe, Mn, Zn, Cu, C and MOS and calculated soil bulk density, total porosity and relative density. In Saúba retiro, with less time management, soils of Caiçara, Plantio and Lavrado with higher clay, no differences in pH, but there was a significant reduction in Al content available in areas with manure. All the nutrients, except for Zn and Cu concentrations were higher in areas Plantio over the Lavrado, as well as the C and MOS. Only Mg and K were higher in the soil Caicara compared with the adjacent Lavrado. In retiro Rebolada there were no differences in soil pH between treatments. Al was lower in soils of Caiçara and Plantio compared with Lavrado, at 0-10 cm. The Ca and Mg showed significant differences between treatments at 0-10 cm, with higher values at Plantio followed by Caiçara and Lavrado. The K was higher in Plantio depths of 0-10 and 10-20 cm, while the P was significantly higher in Plantio in 3 layers. Regarding micronutrients, the levels of Fe were higher in Plantio and Caiçara while Zn and Mn were higher only in Plantio. The Cu was higher in Caicara 20-30 cm layer. The values of C and MOS this retiro were higher in Plantio in 3 layers analyzed. The retiro Aningal, the oldest community and sandy soil, showed no differences in pH and concentrations of Al, K and P between treatments in three depths. Ca levels were higher in the plantation compared to Lavrado and did not differ in Caiçara. The Mg was higher in Plantio in the deeper layers. The Fe was higher in the plantation, while Mn was higher in Caiçara only at 0-10 cm, Cu showed differences only in the superficial layers, whereas Zn did not differ between treatments. The contents of C and MOS were higher in Plantio and intermediaries in Caiçara, up to 10 cm in depth. In the depth of 10-20 cm no differences, while in the layer of 20-30 cm, only the C was higher in the Plantio. As for soil physical properties, only the retiro Saúba differ between treatments at 0-5 cm. The densities of the soil and Plantio were lower relative to the Caiçara and Lavrado, and total porosity was reversed. The depth of 5-10 cm showed no differences between treatments for the attributes. Treatments in other retiro showed no differences in the physical characteristics of the soil. The results showed that soil embossed naturally possess undesirable physical characteristics such as high density and low porosity, and management of cattle in Caiçaras fails to change these characteristics, but the addition of manure in Plantio can improve them.