João Luiz Lani

Pedossistemas da Mata Atlântica: considerações pertinentes sobre a sustentabilidade

A pedological analysis was carried out on the ecologically important Atlantic Forest system, as a contribution to the study of its biodiversity. Focus is placed on some factors that can influence local diversity, such as soil depth, that varies within short distances. The reasons for prohibiting the cultivation of hilly soils by small farmers is also questioned. It is suggested that radiation, water and nutrient resources, should be emphasized, since they are essential to ecosystem functioning, instead of indirect variables. Based on pedological information, ten great environments in the Atlantic Forest were identified. Comments related to water and nutrients, and observations related to use, fragility and ecological importance are made about each stratified ecosystem. Two great ecosystems are indicated as potentially very important to diversity: shallow soil areas and rock outcrops and humic soil areas (a very important carbon sink), in the higher portions of the landscape.

Estratificação e caracterização ambiental da área de preservação permanente do Rio Guandu/RJ

RESUMO – O Rio Guandu e a principal fonte de abastecimento de agua da regiao metropolitana do Rio de Janeiro, atendendo a, aproximadamente, nove milhoes de pessoas. Este trabalho estratificou e caracterizou ambientalmente a Area de Preservacao Permanente (APP) do Rio Guandu (faixa marginal de 100m), atraves da analise de aerofotos digitais nao convencionais, obtidas a partir de uma câmera digital de pequeno formato, adaptada a um helicoptero (as aerofotos foram agrupadas em mosaicos para facilitar as etapas do geoprocessamento). A regiao correspondente a APP foi estratificada em quatro ambientes com caracteristicas ecologicas distintas: Ambiente 1 (leito encaixado), Ambiente 2 (varzea fluvial), Ambiente 3 (planicie aluvionar) e Ambiente 4 (fluviomarinho). A partir da sobreposicao dos mapas de uso da terra, da proximidade da area urbano-industrial e da vegetacao nativa, foi gerado um mapa do grau de degradacao dos ambientes. Os usos predominantes foram pastagem (38%) e agricultura (18%). Os fragmentos florestais totalizaram apenas 11,6% da APP. Segundo a metodologia utilizada, o Ambiente 4 apresentou 51% de sua area, com um grau alto a muito alto de degradacao, e o Ambiente 3 apresentou melhor estado de conservacao em comparacao aos demais. Os resultados sugeriram que a predominância das atividades agropecuarias, a proximidade de grandes centros urbanos e a area muito reduzida dos fragmentos florestais na APP do Rio Guandu podem comprometer a qualidade desse manancial.

Mosaico digital de aerofotos não-convencionais na avaliação de recursos naturais: estudo de caso

Pelo presente trabalho avaliou-se a utilizacao de aerofotos nao-convencionais na forma de mosaico digital, como ferramenta basica no levantamento de solos e seu uso. O aerolevantamento foi realizado em quatro microbacias do municipio de Guarapari, ES. Foram feitas oito faixas de sobrevoos fotograficos com recobrimento longitudinal de 60% e lateral de 40%. A partir da digitalizacao de fotografias com elementos no tamanho 9 x 9 cm na escala aproximada de 1:25.000, produziu-se um mosaico digital com o auxilio do software Visual Stitcher. Os mapas de solos e de uso da terra foram delineados sobre o mosaico georreferenciado, com a utilizacao de digitalizacao em tela do software Idrisi 32. O uso do mosaico digital facilitou e agilizou o processo de mapeamento dos solos e da delimitacao do uso da terra na area estudada.

Espacialização da precipitação pluvial por meio de krigagem e cokrigagem

The objective of this work was to evaluate the ordinary co-kriging algorithm, using data from elevation and distance from the sea, compared to ordinary kriging, in the rainfall spatialization associated to wet, dry and annual periods, for the state of Espirito Santo, Brazil. Data of altitude and distance from the sea were obtained in sampling sites on regular and irregular grids. Data from 108 rain gauge stations were used. The evaluation of methods and variables based on cross-validation was performed, considering the errors of the predicted values and the fit of linear regression models for observed and predicted values. The regular grid sampling of the covariates showed the best prediction accuracy compared to the irregular grid. Cokriging produced more accurate results than kriging, checked by small differences in mean absolute errors which were able to produce statistically different maps. Cokriging interpolation and use of regular grids for sampling are preferable, mainly if the covariates are easy to obtain and inexpensive.

Solos, manejo e aspectos hidrológicos na bacia hidrográfica do Araújos, Viçosa - MG

When comparing the past and the current data referring to flow rate in Sao Bartolomeu creek, Vicosa - MG, it was found that some deregulation has occured in the last decades. The objective of this work was to study the influence of physical characteristics of two types of soils (Yellow-Red Latosol - LVA and Red Argisol - PV) under pasture as well as the implantation of some practices for both management and soil and water conservation in the hydrological behavior in Sao Bartolomeu creek microbasin. The monitoring of precipitation, flow rate of the water and the water level in the water tables were assessed before and after implantation of the management and conservation techniques. The soil clay contents were higher in LVA compared with PV, however indicating no correlation with the results for the soil density and porosity, but affecting both water retention into soil and the hydraulic conductivity, therefore the water retention in LVA was higher than PV. The water table variation was more sensitive in PV as a result from the association of the physical characteristics of this soil and the management techniques applied. As a result, the minimum flow rate referring to 2004 was 188 L.min-1, which in comparison with the minimum flow rate of 80 L.min-1 referring to 2002 indicates an increment of 108 L.min-1 (135%) which confirm a tendency of the of a positive action of the soil conservation techniques in provisioning the water depth associated to the importance of knowing the characteristics of the soil, the use which it has been submitted to and its relationship with the hydrological cycle.

Aptidão agrícola e algoritmos genéticos na organização espacial em projetos de reforma agrária

The definition of family settlement plots in land reform projects involves technical and social issues. These aspects are mainly related to differences in the agricultural suitability of the soil in these projects. The objective of this study was to introduce a procedure for an optimal subdivision of the land by cross-linking projects by a Genetic Algorithm (GA). The GA was tested in the rural settlement Veredas, located in Padre Paraiso, in the region of the Vale do Jequitinhonha, State of Minas Gerais, Brazil. It was implemented based on the soil suitability and productivity index.

O conhecimento local e a etnopedologia no estudo dos agroecossistemas da comunidade quilombola de Brejo dos Crioulos

This work sought to identify, rescue and value the traditional knowledge about soil and environment, establishing a relationship of this knowledge with scientific knowledge of academic slant. To this end, it was the stratification of the environment of the marron territory of Brejo dos Crioulos, based on local criteria and pedological conventional method, considering the soil and its interface with other environmental components. Associated with the characterization of agroecosystems, with interpretation and recognition of the logic of traditional knowledge use and management of natural resources, by contacting the maroons recognize the best time (time), the environment (soil, moisture, microclimate), the species and variety, combining activities, and casting a set of practices that allow the survival of their families. The community of Brejo dos Crioulos dominates its own system of stratification of environments, whose identity enables comprehensive reference to scientific knowledge and articulation academic. The construction of identification keys of environments based on the criteria of the maroons, combined with information obtained based on local knowledge, to deepen the characterization of environments and mapping of soils contributed to a better understanding of the strategies of agrifood maroon, achieving results that can support planning processes and definitions of public policies for sustainable land use territory of maroon.

Sistemas de classificações geotécnicas de solos: estudo de caso aplicado à rodovia não pavimentada vcs 346, Viçosa, MG

RESUMO – Este artigo aborda uma contribuicao as classificacoes geotecnicas tradicionais de solos Unified Soil Classification System (USC), Transportation Research Board System (TRB) e a Metodologia Miniatura, Compactado, Tropical (MCT) para um caso aplicado a rodovia municipal nao pavimentada VCS 346, no Municipio de Vicosa, MG, considerando-se varias amostras deformadas de solos coletadas no subleito da referida via. Os principais objetivos deste estudo residem na contribuicao de um banco de dados geotecnicos sobre classificacoes de solos tropicais, bem como na verificacao de possiveis agrupamentos entre os sistemas geotecnicos tradicionais de classificacao e a metodologia MCT. O programa de laboratorio envolveu a realizacao dos seguintes ensaios: (i) granulometria conjunta; (ii) limites de Atterberg (LL e LP); (iii) massa especifica dos graos do solo; (iv) compactacao Mini-MCV; e (v) perda de massa do corpo-de-prova por imersao em agua. Os resultados possibilitaram verificar que, apos a classificacao das amostras, varios agrupamentos entre os sistemas de classificacoes geotecnicas tradicionais coincidiram com aqueles ja apresentados na metodologia MCT e, considerando a pedogenese da regiao de Vicosa, MG, para o grupo NG’, houve a contribuicao dos grupos SC, SM e CL do Sistema USC e do grupo A-4 do Sistema TRB.

Proposta metodológica para o cálculo de espaçamento entre sulcos de mulching vertical

Proposed methodology for determination of vertical mulching spacing Vertical mulching is a method for containment of runof f that despite promising is still being validated. Thus, this study aimed to propose and test a methodology for calculating the row spacing of vertical mulching, and efficiency in reducing losses of water, soil and nutrient by runof f in the field. The experiment was conducted from october 2009 to march 2010 during the corn (Zea mays) crop cycle in a consolidated no-till area. We used a randomized block design with four replications and six treatments consisting of vertical mulching furrows opened perpendicularly to the slope, distributed at different distances. In runoff samples, the following attributes were analyzed: volume of water lost, soil mass in the sediment, nutrients in the sediment and water runoff. There were no significant differences for the effect of

Morphological, physical and pedogenetic attributes related to water yield in small watersheds in Guarapari/ES, Brazil

Soil characteristics related to the genesis, land use and management are important factors in water dynamics in watersheds. This study evaluated physical, morphological and pedogenetic attributes related to water yield potential in small watersheds in Guarapari, ES, Brazil. The following representative profiles were selected, morphologically described and sampled in area of Atlantic Forest domain: Lithic Udifolists, Oxyaquic Udifluventes, Typic Paleudults, Typic Hapludults, Typic Hapludox, Oxic Dystrudepts and Typic Endoaquents. Samples were collected in the soil profiles for physical analysis. Measurements of field-saturated hydraulic conductivity and soil penetration resistance were perfomed in some profiles, which were under different uses. The Endoaquents of Limao Creek can be considered efficient as temporary water reservoirs. However, the use of artificial drainage tends to reduce this ef fect. Differential erosion was detected by the sand texture on the surface of the Typic Paleudults due to the low degree of clay flocculation, slope, high resistance to the penetration and low hydraulic conductivity of the Bt horizon, making it necessary to adopt soil management practices to increase the water infiltration. Under pasture, mainly in the cattle trails where the trampling is more intense, there was high resistance to penetration in the superficial layers of the Typic Hapludults. The Typic Hapludox have the greatest potential for water yield in the small watersheds because of its greater extent in the headwaters and their morphological and physical characteristics, which can result in increased aquifer recharge.