Ronaldo Luiz Mincato

SPATIAL AND TEMPORAL MODELING OF WATER EROSION IN DYSTROPHIC RED LATOSOL (OXISOL) USED FOR FARMING AND CATTLE RAISING ACTIVITIES IN A SUB-BASIN IN THE SOUTH OF MINAS GERAIS

Water erosion is one of the most important soil degradation processes and it can be intensified by land use and vegetal covering changes. Thus, water erosion modeling studies associated to multi temporal analyses of land use are effective in assessing how changes in land cover affects sediment yield. Therefore, considering the modifications in the land use from 1986 to 2011, the aim of this study ranged to estimate water erosion rates and compare them to the soil loss tolerance (SLT) limit in the Latosols (Oxisols) at Ribeirao Cacus sub-basin, in the South of Minas Gerais State, Southeast Brazil, by means of the Revised Universal Soil Loss Equation (RUSLE) in association with the geographic information system (GIS), and geostatistical techniques. So, for each year mapped, soil loss averages were compared by t test at 5% significance to assess the soil degradation stage. The results indicated that, in the period, the soil loss average rate was from 2.4 to 2.6 Mg ha-1 year-1 and the areas with soil loss above the limit of SLT were around 8.0%. The t test demonstrated there was no considerable difference among the soil loss averages (p = 0.18). In consequence, the area of degraded soils did not increase. Thus, the RUSLE model in GIS is a simple and useful tool to estimate the soil loss and help define soil conservation and recovery measures.

Heavy metals availability and soil fertility after land application of sewage sludge on dystroferric Red Latosol

Sewage sludge is the solid residue obtained from urban sewage treatment plants. It is possible to use the sludge in a sustainable way as fertilizer and as soil conditioner due to its high levels of organic matter and nutrients. Besides pathogens and volatile organic compounds, the residue may also contain heavy metals which may accumulate and contaminate crops and the food chain. The aim of this study was evaluates the changes in the fertility of dystrophic Red Latosol and in the availability of heavy metals following application of sewage sludge. It was assessed whether organic matter supplied to the soil as large amounts of sewage sludge would decrease availability of heavy metals in the soil due to of insoluble compounds formation. From this, an experiment was carried out in polyethylene pots using lettuce plant for test. Sewage sludge were applied to the soil in concentrations equivalent to 60, 120 and 180 t ha-1, and a control without sludge, in four replicates, in a completely randomized design. The results show that sewage sludge led to an increase of organic matter contents, of the cation exchange capacity (CEC) and of nutrients found in the soil. It also improved plant growth up to a concentration of 120 t ha-1. Availability of heavy metals, however, was reduced in sludge concentrations starting with 120 t ha-1.

Environmental quality of an urban sub-basin: a study case of Alfenas – MG

The cities expansion conditioned by the urban population increase exerts considerable ecosystems pressure, often leading them to high degradation stages. The use of proceedings and techniques that evaluate current conditions and possible future scenarios are indispensable, seeking sustainability for socioeconomic development and environmental protection. Therefore, a Rapid Assessment Protocol was applied to evaluate parameters of urban environmental and water quality of the Corrego do Pântano 1 Hydrographic Sub-basin, Alfenas - MG, located at the municipality periurban limit, important area for the provision of environmental services and a response indicator to the urban processes on the natural environment. Thus, weights were distributed for the environmental quality indicators and, for each variable, was designated a note, making possible the composition of a scenario of the environmental conditions of the studied sites. It was verified that the application of the Rapid Assessment Protocol is an efficient means for directing public policies aimed at mitigating the impacts caused by cities on the environmental and water quality of sub-basins under urban influence. It is recommended the implementation of a sub-basin management plan with guidelines that embrace the conservation of the area mainly directed to the recovery of native vegetation and inspection of the urban effluents emission.

Land use capacity and environment services

The increasing demand for food resulting from demographic growth has required more productive agropastoral practices. Consequently, new areas were selected for agropastoral production in an arbitrary way, disregarding land use capacity. This ends up in acceleration of degradation processes, mainly those related to water erosion. In this context, the system of land use capacity proposes the classification of maximum use allowed for land of a rural property or of a hydrographic sub-basin, in an attempt to make sustainable plans of use and management of natural resources. Concerning current use of land, the system indicates the sites where there are conflicts in use in relation to their use capacity. Thus, it is possible to propose measures to adapt land use to its use capacity. Therefore, in this study, the classes of land use capacity at the hydrographic sub-basin of Corrego Pedra Branca, in Alfenas, in the state of Minas Gerais, were evaluated. For that purpose, the following soil parameters were evaluated: effective depth, water permeability, texture, declivity, erosion class, base saturation, effective and potential cationic exchange capacity, and aluminum saturation. Soil analyses presented values of base saturation and of low capacity of effective and potential cationic exchange, which illustrate the low natural fertility of these soils, as well as aluminum saturation level harmful to most cultures. Thus, land use would be restricted to low impact, permanent crops, silvicultures, associated agrosilvipastoral system with conservationist management techniques, as, for example, direct seeding, soil correction and fertilization, and reforestation of permanent preservation areas

Multitemporal analysis of land use types using Landsat-5 TM images in the region of Alfenas, South of Minas Gerais, aiming the conservation of native forest fragments

Several studies have shown that native forest fragments surrounded by different land-use matrixes undergo different ecological pressures on fauna and flora. In light this, we studied the land-use and land-cover changes in the region of Alfenas, southern Minas Gerais state, aiming the conservation of forest fragments. Landsat-5 Thematic Mapper (TM) images, bands 1 to 5 and 7, from 1987 and 2011, were used. Image classification was achieved using the Geographic Data Mining Analyst (GeoDMA), a toolbox specially addressed for spatial data mining. To carry out this investigation, the following procedures were adopted: image segmentation, spectral and spatial features extraction, sampling, decision tree generation, classification, error edition, and analysis of land-use and land-cover changes by using a change detection matrix. The results showed the importance of complementarity of information available in each band for classifying different land use and land cover types. As for land use change, an increase of sugar cane, coffee and bare soil were registered on previously areas used for pasture. Such information are important, since they may support interpretations of ecological dynamics of forest fragments.

Attributes of dystrophic latosol in southern minas gerais after application of sewage sludge

Endereço para correspondência: Ronaldo Luiz Mincato – Rua Gabriel Monteiro da Silva, 700 – Centro – 37130-000 – Alfenas (MG), Brasil – E-mail: ronaldo.mincato@unifal-mg.edu.br ABSTRACT In general, tropical soils present low natural fertility, which results in a great amount of degraded areas if it is associated with improper handling. Sewage sludge, due to its high levels of organic matter and nutrients, can improve soil properties. Thus, this study evaluated the conditioning and fertilizing effects of sewage sludge on the attributes of a typical dystrophic latosol in Southern Minas Gerais. The experiment evaluated the application of sludge from Santana wastewater treatment plant in Varginhas (Minas Gerais, Brazil) in pots, with concentrations equivalent to 60, 120, and 180 t ha-1, and a control treatment without sludge. The sewage sludge has increased the levels of organic matter, cation-exchange capacity, sum of the bases and nutrients, as well as increased porosity and decreased soil density, thus indicating the potential for conditioning and fertilizing agricultural soils.