Regina Márcia Longo

Alterações em características químicas de solos da região amazônica pela introdução de pastagens

The aim of the present work is to evaluate the effects of the human intervention, through the introduction of pasture, in some chemical properties of the Amazon soil. This research was installed in Porto Velho, State of Rondonia - Brazil, located vicinity of the Empresa Brasileira de Pesquisa Agropecuaria (Embrapa). The samples were accomplished in areas of primary vegetation and planted pasture (about 15 years), obeying a line with 24 points each 10 meters (12 under natural vegetation and 12 under pasture) in two horizons (superficial and undersuperficial). The results obtained for chemical compounds showed significant between forest and pasture to V%, CEC, C+Al, N-total and C-organic, mainly in the superficial horizon of the original vegetable. The higher organic compounds (N-total, C-organic) and P, Ca e Mg, in the superficial horizon of natural vegetation, wintry in Amazon Forest were observed.

Atividade da urease em latossolos sob influência da cobertura vegetal e da época de amostragem

The present study aimed to evaluate the effect of the vegetation type and the sampling time on urease activity in two different tropical soils (Rhodic Oxisols). The experiment was installed in a typic alumino-ferric Red Latossol and a typic distrophic Red Latosol under five different vegetations: pinus, eucalypt, citrus, soybean and corn. The soil samples were collected from April 1990 to March 1991 and the urease activity, total nitrogen and organic carbon were determined. The urease activity changed according to the sampling time, presenting higher values in the warmer and humid months. The vegetation type affected the conversion of N-urea to N-NH4+, with higher urease activity being observed in the soil under pinus and eucalypt, although the activity was high at the beginning of the soybean and corn cropping cycle.

USO DE FOTOGRAFIAS HEMISFÉRICAS PARA AVALIAÇÃO DA QUALIDADE AMBIENTAL NA MATA DE SANTA GENEBRA, CAMPINAS-SP, BRASIL

Currently, the development of large centers has exerted constant pressure on the remaining forests located in urban areas. The study of environmental impacts to which they are exposed allows better management and conservation of forest remnants located in this areas . In this context, the present study aimed to evaluate the impacts of degradation in forest border areas and inside of Mata de Santa Genebra, a forest remnant constituted 85% of semideciduous forest, located in Barao Geraldo district (Campinas, SP) belonging to Ribeirao das Pedras river basin. They took up 19 points within the remaining, three photos were taken for each point, equidistant 200 meters from each other and each at a distance of 5 meters from the traversed tracks. Additionally, 40 points in the remainder of the edge area, also discussed in triplicate, equally spaced 200 meters apart and each at a distance of 10 meters from the edge of the forest fragment. The results lead to the conclusion that in the winter, through the Leaf Area Index analyzes, the edge of the remaining forest is more degraded in the interior, including point out of the places where degradation had become more pronounced and they need more emergency actions for their recovery. These results are probably due to anthropogenic influences present in the studied forest stretches.

Water Quality Index In An Urban Watershed

This study aimed to verify the water quality of Ribeirão das Pedras (Stones River), Campinas, São Paulo, Brazil through the implementation of the Water Quality Index (WQI) and comparison with Brazilian legislation (Resolution of the National Environment Council – CONAMA 357/2005), thus being able to initiate discussions about anthropic interferences in watercourses located in urban areas. Ribeirão das Pedras is part of an urban watershed that suffered, and still suffers, from the rapid and intense urban and housing boom, finding its territorial space almost fully occupied. For the execution of this work, six sample points were defined in order to allow a discussion between the land use within their respective drainage area and the results of the WQI applications. The WQI is composed of nine parameters: dissolved oxygen, biochemical oxygen demand, nitrogen, temperature, thermotolerant coliforms, turbidity, phosphorus, pH, and total solids. The first sample point refers to the main watercourse source, four sample points are located throughout the watershed and the last point is located in its base level, at the confluence between Ribeirão das Pedras and its main stem, Ribeirão das Anhumas (Anhumas River). The results of water quality analysis obtained based on the WQI concept were featured as ‘GOOD’; however, the isolated analysis of each parameter allows to compare them with the Brazilian legislation, where it appears that none of the points meets all established quality parameters. Thus, it can be concluded that the watercourse suffers significant impacts along its course, probably derived from the use of the surrounding drainage areas.