Suzana Ferreira da Rosa

PROPRIEDADES FÍSICAS E QUÍMICAS DE UM ARGISSOLO SOB CULTIVO DE Eucalyptus dunnii Maiden NO PAMPA GAÚCHO

The conversion of natural vegetation to cultivated areas as well as changes in vegetation cover can lead to changes in some soil properties, interfering on their quality. Such changes occur in the soil structure and in the chemical properties. Therefore, the study has the objective to evaluate the changes in the physical and chemical properties of an Ultisol after afforestation of Eucalyptus dunnii Maiden planted in different spacing resulting in several plant populations. The study was accomplished in ‘Campanha Gaucha’ region, in Sao Francisco de Assis city, Rio Grande do Sul state (RS). It was carried out an experiment planted with Eucalyptus dunnii Maiden planted on Ultisol with native grass. The plant spacings used were: 3,50 m x 3,50 m; 3,50 m x 1,75 m; 1,75 m 1,75 m and 1,75 m x 0,87 m. The experimental design was a complete randomized block with four replicates. It was collected soil samples were taken before the Eucalyptus planting and after twelve months, and layers of 0,00-0,10 m; 0,10-0,20 m and 0,20-0,40 m. The soil physical properties measured were: bulk density, total, macro and microporosity and wet aggregate size distribution. The soil chemical measured were: water pH, Al +++ , Ca ++ , Mg ++ , K + , available P, N and C. There were change in the macro and microporosity, in the percentage of stable aggregates of size class 8,00-4,75 mm and DMG because to soil tillage and forest management. For the chemical properties there were increase in the pH and Ca content in the soil after twelve months by effect to fertilization applied.

AGREGAÇÃO DE UM CAMBISSOLO HÚMICO EM POVOAMENTOS DE Pinus taeda L. COM DIFERENTES ROTAÇÕES

The study aims to verify whether the introduction of the specie Pinus taeda L. in soil under natural field alters the aggregation of Haplumbrept, at differents rotations. The study was conducted in the region of Campos de Cima da Serra, in the municipality of Cambara do Sul – RS state, Brazil. In order to achieve the goal above described, were selected two study areas, one in the first rotation (RT1) and another in the second rotation (RT2), with 13 years of old. For each stand, a combined area of natural field adjacent (control) was assessed. In each area, five trenches were opened and soil samples collected at depths from 0.0 to 0.05, 0.05 to 0.20 and 0.20 to 0.40 m to determine the percentage stable aggregates in each class (AGRI) and geometric mean diameter water stable aggregates (DMG). There was no change in the aggregate stability in the surface layer (0.0 to 0.05 m). However, the subsurface layers (0.05 to 0.20 and 0.20 to 0.40 m), just RT1 maintained stability of larger aggregates. Due to management adopted in RT2, such as burn and clear cut, there was a reduction in stability and increase in macro-aggregates smaller aggregates, whereas in the natural field stability in depth was maintained.

QUALIDADE QUÍMICA DO SOLO COM DIFERENTES NÍVEIS DE DEGRADAÇÃO EM ÁREA DE PRESERVAÇÃO PERMANENTE

CHEMICAL QUALITY OF SOIL WITH DIFFERENT LEVELS OF DEGRADATION IN THE ENVIRONMENTAL PERMANENT PRESERVATION AREAS The objective of this study was to investigate possible effects of soil contamination from pollution by urbanization and inordinate use of the course on the shores of the Sanga Lagoao of Ouro through soil chemical variables analyzed with multivariate statistical tools. We established five sampling points in the path of urban Sanga that have different uses and management. Alterations in the characteristics of soil in accordance with the management imposed. Similarity was observed the formation of three patterns chemical characteristics: soil fertility (1), acidity (2), and the amount of MO, N and K (3) in the soil. Four factors (represented by F1, F2, F3 and F4), explained 88.34% of the total variation of the data, and the factor F1 is the greatest explanation of the SZYMCZAK, v(10), no 10, p. 2158 – 2169, OUT-DEZ 2012.

Enraizamento de estacas de duas espécies de Salix com vistas à estabilização de taludes fluviais.

This study aims to determine biotechnique aptitude of two species of Salix (Wicker-yellow and Wicker-red) in works of bioengineering, by examining the rooting and the time of collect of sticks. The experiment was conducted at Federal University of Santa Maria, with monthly collects of vegetative material, for one year. The stakes, with 40 cm long and variable diameter, were kept in water for 60 days for counting the number and measuring the length of the roots issued. The biggest production of roots for the two species occurred in March and April. In summer, it was more difficult to issue roots, especially for sticks collected in December. For this collect, it was not observed issuing of roots in the period of two months of observation. The Wicker-yellow produced roots bigger than red-Osier, in mostly months of collect. The diameter of the sticks influenced significantly production roots of both species, in several months of collect. This study also shows that the two species of Salix have good biotechnique aptitude to bioengineering works.

Aspectos florísticos e fitossociológicos da reserva Capão de Tupanciretã, Tupanciretã, RS, Brasil.

This work was accomplished in Capao de Tupancireta Reservation, in the city of Tupancireta, Rio Grande do Sul, in an area with 8 hectares, belonging to the Fundation of Agropecuary Research of Rio Grande do Sul. The objective of the paper was to evaluate the floristic composition and the phytosociological structure of the forest. Ten samplings of 10 x 20 m were distributed systematically in the area. In the sampling module, every individual with DAP major or equal to 5 cm was measured and identified. In the sampling, a split sample of 5 x 5 m was marked to evaluate the bush component (DAP between 1 and 5 cm) and one of 2 x 2 was used to evaluate the regeneration (DAP smaller than 1 cm and higher than 30 cm). The results were analyzed considering the FITOANALISE program, it was calculated the traditional phytosociological parameters like density, dominancy, frequency, importance of the value, coverage of the value and index of the diversity. The most present species in the tree component of the forest were Cupania vernalis Cambess. and Sebastiania commersoniana (Baill.) L. B. Sm. & Downs. The biggest number of species in the bush component and in regeneration were Cupania vernalis Cambess., Brunfelsia australis Benth., Allophylus edulis (A. St.-Hil. Cambess. & A. Juss.) Radlk. and Nectandra lanceolata Nees.