Leandro Campos Pinto

Agricultural watershed modeling: a review for hydrology and soil erosion processes

Modelos tem sido usados pelo homem ha milhares de anos para controlar seu ambiente de uma maneira favoravel para melhores condicoes de vida para os humanos. O uso de modelos hidrologicos tem sido uma ferramenta muito eficaz para apoiar os decisores que lidam com as bacias hidrograficas para subsidiar diversas atividades economicas e sociais, como o abastecimento publico de agua, geracao de energia, e a disponibilidade de agua para a agricultura, entre outros. Objetivou-se, nesta revisao, discutir brevemente alguns modelos muito aplicados ao estudo do movimento da agua e solos em paisagens (RUSLE, WEPP, GeoWEPP, LASH, DHSVM and AnnAGNPS), para fornecer informacoes sobre os mesmos, para auxiliar no entendimento adequado de problemas especificos relacionados com os processos de hidrologia e erosao do solo. Modelos tem sido alterados e avaliados de forma significativa nos ultimos anos, com destaque para o uso de sensoriamento remoto, GIS e processo de calibracao automatica, permitindo aos mesmos que sejam capazes de simular bacias hidrograficas nas suas condicoes atuais de uso do solo e mudancas climaticas. No entanto, os modelos hidrologicos tem quase a mesma estrutura fisica, o que nao e suficiente para simular problemas relacionados com os efeitos a longo prazo de diferentes usos do solo. Esse tem sido um dos principais desafios para o futuro: compreender inteiramente o ciclo hidrologico, tendo como referencia a zona critica, na qual os processos hidrologicos agem em conjunto a partir do dossel ate a base dos aquiferos.

PARTIÇÃO DA PRECIPITAÇÃO PLUVIAL EM UMA MICROBACIA HIDROGRÁFICA OCUPADA POR MATA ATLÂNTICA NA SERRA DA MANTIQUEIRA, MG

The analyze of pluvial precipitation and its interaction on the different hydrologic cycle phases in forested watersheds are essential in order to water balance characterization due to its relevant participation in the hydrological processes and to its spatial-temporal variability as function of edaphic, topographic, climatic and vegetation elements. Due to heterogeneity of Atlantic Forest associated to temporal and spatial variability of pluvial precipitation regime, the study of mechanisms that allow describing and linking the hydrological cycle elements are very important. This way, the objective of this study was to analyze the partitioning of pluvial precipitation at a micro-catchment entirely occupied by Atlantic Forest remnant, in Mantiqueira Range, during 2009/2010 and 2010/2011 hydrological years, relating it with the seasonal evolution of this ecosystem which was monitored by the application of normalized difference vegetation indexes (NDVI). It was observed greater percentage of internal pluvial precipitation during the periods with less rainfall. It was also verified greater water storage capacity of the Atlantic Forests canopy throughout rainy season. Yet, a plausible correlation was obtained between water storage capacity of Atlantic Forest and the regeneration of vegetation demonstrated by NDVI what can be associated to the processes responsible for Atlantic Forests growth.

Role of Inceptisols in the Hydrology of Mountainous Catchments in Southeastern Brazil

AbstractMantiqueira Range is the most important headwater region in southeastern Brazil, being responsible for streamflows that feed a significant part of Brazilian hydroelectric energy production. This region is extremely fragile with endemic species like those that compose the upper mountain cloud forest (UMCF), and the dominant soils are typical Inceptisols. These forest environments are rapidly disappearing in Brazil. The changing land use combined with shallow Inceptisols lead to important effects on hydrology. Therefore, studies addressing streamflow behavior in these landscapes are urgently needed for understanding the groundwater recharge process. The objectives of this study were to investigate the role of shallow Inceptisols linked to the land use changes in the streamflow behavior of the Mantiqueira Range region and to understand the mechanisms of water flow into the saturated zone. To validate the study, a comparative analysis was developed for a representative watershed of Mantiqueira Range, ...

MICROMORPHOLOGY AND PEDOGENESIS OF MOUNTAINOUS INCEPTISOLS IN THE MANTIQUEIRA RANGE (MG)

Understanding soil formation processes across different landscapes is needed to predict how soil properties will respond to land use change. This study aimed to characterize mountainous Inceptisols (Cambisols) under high altitude subtropical climate in southeastern Brazil, by soil physical, chemical and micromorphological analyses, under native forest and pasture. The soil under pasture had a greater bulk density than under forest, resulting in a severe reduction of macroporosity. At two depths, coarse quartz grains are angular, suggesting absence of transportational processes, thus confirming an autochthonous pedogenesis from the underlying gneissic rock. Most feldspars were weathered beyond recognition, but mineral alteration was commonly seen across cleavage plans and edges of micas. The micromorphological results suggest an intermediate stage of mineral weathering and soil development, which is in accordance with properties expected to be found in Inceptisols.

Water quality indicators in the Mantiqueira Range region, Minas Gerais state

Maintaining the quality of water resources is of great importance for environmental preservation and the quality of life of consumers, and is one of the greatest challenges facing humanity today. Land-use for agriculture and animal farming significantly changes the biological, physical and chemical characteristics of natural systems. This study comprised monitoring of two subbasins located in the Mantiqueira Range region, from which water samples were collected on a monthly basis between June 2010 and May 2011 for analysis. Each subbasin has a distinct vegetation cover, one being predominantly covered by pastureland and the other being entirely covered by Atlantic Forest. The following water quality indicators were analyzed: turbidity, pH, electrical conductivity, total dissolved solids, dissolved oxygen, temperature, nitrate, phosphate, BOD,COD, total and fecal coliforms, and respective discharge measurement. The results showed that water quality degradation in both environments coincided with the local rainy season and was influenced by transport of organic material to watercourses by direct surface runoff. The high concentrations of fecal coliforms found affected the water quality, particularly in the rainy season, and are associated with agriculture and animal farming, the main economic activities in the region. The Atlantic Forest environment, however, had statistically better water quality over time in relation to the pastureland environment, due to the buffering it provides to direct surface runoff.

Water quality index in two land use situations in the Mantiqueira Range

A utilizacao de um grande numero de indicadores de qualidade de agua torna oneroso o monitoramento dos corpos hidricos a longo tempo. Nesse sentido, a Analise de Componentes Principais (ACP) pode ser considerada como uma tecnica promissora de grande auxilio na gestao dos recursos hidricos, pois permite diminuir a dimensionalidade dos dados, facilitando a sua analise. Neste estudo, objetivou-se obter um indice de qualidade de agua (IQA) para a regiao das nascentes do Rio Grande, na Serra da Mantiqueira, Minas Gerais. Na composicao do IQA, foi realizada a normalizacao dos resultados de indicadores de qualidade de agua advindos de uma sub-bacia sob a Mata Atlântica e outra predominantemente sob pastagem. Esses valores normalizados foram submetidos a uma ACP e, posteriormente, foi efetuado o calculo do IQA. Os indicadores com maiores pesos, segundo a ACP, foram o coliforme total, nitrato, coliforme termotolerante, demanda quimica de oxigenio e temperatura. A sub-bacia sob Mata Atlântica apresentou os melhores resultados de IQA, denotando a importância desse tipo de ambiente na manutencao da qualidade da agua dos mananciais na regiao da Serra da Mantiqueira.

Similar Soils but Different Soil-Forming Factors: Converging Evolution of Inceptisols in Brazil

Abstract Soils result from the interaction of five independent formation factors. If one factor varies, while the others remain constant, different soils can be produced. Herein, we demonstrated an opposing trend, wherein two soils were similar, despite considerable differences in all factors of soil formation. We sampled two Inceptisols (Oxic Dystrudepts) formed on different parent materials (gneiss vs. mica schist), climate (tropical altimontane vs. warmer, drier plateau), topography (1 650 m, 45% slope vs. 1 000 m, 8% slope), time (rejuvenated vs. old, stable surface), and vegetation (rainforest vs. Cerrado savanna). The two soils had similar chemical properties, whereas the soil on mica schist had finer particle size distribution, lower porosity, and lower saturated hydraulic conductivity. These properties were related to a coarser blocky microstructure compared to the soil on gneiss. Both soils presented active mineral weathering and pronounced pedoplasmation, demonstrated by clay contents > 300 g kg −1 , although only the Dystrudept on gneiss possessed coarse rock fragments. The C horizons of both soils presented fragmented clay coatings suggestive of argilluviation, likely relict, because they were not observed in the B horizons. The similarities in many properties of the two Dystrudepts, despite contrasting factors of soil formation, suggest converging evolution and that soil classification at the subgroup level was efficient in grouping similar formative processes in tropical conditions. Moreover, this work revealed that similar pedogenic processes acting on different factors of soil formation can result in similar soil properties, at least for Inceptisols where further soil development is hindered by topographic limitations.

Land-use effect on hydropedology in a mountainous region of Southeastern Brazil

In Brazil, the Mantiqueira Range, southeastern region, shelters the last remnants of the ecologically important Upper Montane Tropical Forest. since extensive exploration that has been taking place in this biome for decades, the influence of land-use changes on hydropedology in these areas must be investigated once major land-use changes have been observed. This study aims to evaluate the land-use influence on soil drainable porosity (SDP) in a headwater watershed located in the Mantiqueira Range region, and to validate the proposed methods based on micromorphological and hydrological indicators. The native vegetation of the study area is Atlantic forest that occupies 62% of the area, and the remaining 38% has been used for pasture. Thirty nine combinations of environmental variables were tested, each one generating a map for predicting SDP. The performance of the spatial prediction of SDP was assessed using 20% of the data from the total number of samples collected throughout the watershed. The least values of SDP are due to the process of removal of native forest and replacement by pasture. Areas with high to moderate SDP are associated with native forest fragments demonstrating the effects of the Atlantic Forest on the water infiltration and groundwater recharge processes, given by the greater contribution of baseflow in a forested catchment located within the studied watershed. The analysis of soil micromorphological images provided useful supporting information on the soil porosity system and along with hydrological properties of the watershed helped understand the SDP behavior on subsurface and groundwater storage capacity.