Predicting Runoff Risks By Digital Soil Mapping

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Digital soil mapping (DSM) permits continuous mapping soil types and properties through raster formats considering variation within soil class, in contrast to the traditional mapping that only considers spatial variation of soils at the boundaries of delineated polygons. The objective of this study was to compare the performance of SoLIM (Soil Land Inference Model) for two sets of environmental variables on digital mapping of saturated hydraulic conductivity and solum depth (A + B horizons) and to apply the best model on runoff risk evaluation. The study was done in the Posses watershed, MG, Brazil, and SoLIM was applied for the following sets of co-variables: 1) terrain attributes (AT): slope, plan curvature, elevation and topographic wetness index. 2) Geomorphons and terrain attributes (GEOM): slope, plan curvature, elevation and topographic wetness index combined with geomorphons. The most precise methodology was applied to predict runoff areas risk through the Wetness Index based on contribution area, solum depth, and saturated hydraulic conductivity. GEOM was the best set of co-variables for both properties, so this was the DSM model used to predict the runoff risk. The runoff risk showed that the critical months are from November to March. The new way to classify the landscape to use on DSM was demonstrated to be an efficient tool with which to model process that occurs on watersheds and can be used to forecast the runoff risk.40Brazilian Coordination for the Improvement of Higher Education Personnel - CAPESBrazilian National Council for Scientific and Technological Development - CNPq [471522/2012-0, 201987/2012-0, 305010/2013-1]Minas Gerais State Research Foundation - FAPEMIG [CAG-APQ-01423-11, CAG-PPM-00422-13]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Predicting runoff risks by digital soil mapping

Digital soil mapping (DSM) permits continuous mapping soil types and properties through raster formats considering variation within soil class, in contrast to the traditional mapping that only considers spatial variation of soils at the boundaries of delineated polygons. The objective of this study was to compare the performance of SoLIM (Soil Land Inference Model) for two sets of environmental variables on digital mapping of saturated hydraulic conductivity and solum depth (A + B horizons) and to apply the best model on runoff risk evaluation. The study was done in the Posses watershed, MG, Brazil, and SoLIM was applied for the following sets of co-variables: 1) terrain attributes (AT): slope, plan curvature, elevation and topographic wetness index. 2) Geomorphons and terrain attributes (GEOM): slope, plan curvature, elevation and topographic wetness index combined with geomorphons. The most precise methodology was applied to predict runoff areas risk through the Wetness Index based on contribution area, solum depth, and saturated hydraulic conductivity. GEOM was the best set of co-variables for both properties, so this was the DSM model used to predict the runoff risk. The runoff risk showed that the critical months are from November to March. The new way to classify the landscape to use on DSM was demonstrated to be an efficient tool with which to model process that occurs on watersheds and can be used to forecast the runoff risk40113CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG471522/2012-0; 201987/2012-0; 305010/2013-1Sem informaçãoCAG-APQ-01423-11; CAG-PPM-00422-1

MANAGEMENT SYSTEMS IN THE EUCALYPTUS FOREST PLANTATIONS AND THE SOIL AND WATER LOSSES IN VALE DO RIO DOCE, MG STATE

A eros\ue3o h\ueddrica \ue9 a principal respons\ue1vel pela perda da capacidade produtiva dos solos sob florestas plantadas e altera\ue7\ue3o da quantidade e qualidade da \ue1gua em sub-bacias. Assim, este trabalho objetivou avaliar a influ\ueancia dos sistemas de manejo adotados nos plantios florestais com eucalipto (eucalipto em n\uedvel - EN, eucalipto em desn\uedvel - ED e eucalipto em desn\uedvel com queima - EDQ) sobre as perdas de solo e \ue1gua por eros\ue3o h\ueddrica em rela\ue7\ue3o \ue0s perdas em floresta nativa (FN), pastagem (PP) e solo descoberto (SD), num Latossolo Vermelho (LV) e Latossolo Vermelho-Amarelo (LVA), e indicar qual o per\uedodo mais cr\uedtico no manejo do solo, em rela\ue7\ue3o \ue0 eros\ue3o h\ueddrica, durante o ciclo de cultivo do eucalipto. O estudo foi conduzido em dois munic\uedpios: Belo Oriente (LVA) e Guanh\ue3es (LV), situados no Vale do Rio Doce, regi\ue3o Centro-Leste do estado de Minas Gerais. Com exce\ue7\ue3o do sistema SD no LVA, as perdas de solo foram abaixo do limite de toler\ue2ncia admiss\uedvel para essas classes de solos, nestas regi\uf5es, que s\ue3o de 11,22 Mg ha-1 ano-1 no LV e de 7,17 Mg ha-1 ano-1 para o LVA. As perdas de \ue1gua nos sistemas com eucalipto foram menores no plantio em n\uedvel, no LVA. Nos sistemas com eucalipto, os per\uedodos iniciais ap\uf3s o plantio apresentam as maiores perdas de solo e \ue1gua com redu\ue7\ue3o ao final do ciclo. Por outro lado, no LVA os sistemas com solo descoberto e floresta nativa apresentaram aumento das perdas de \ue1gua com o decorrer do tempo avaliado, indicando adequa\ue7\ue3o dos sistemas com eucalipto.Water erosion is the main responsible for decreasing the productive capacity of soils under forest plantations and it changes the amount and the quality of water in sub-basins. Thus, this work aimed to evaluate the influence of management systems adopted in Eucalyptus forest plantations (eucalyptus in contour planting - EN, eucalyptus up and downslope planting - ED, and eucalyptus up and downslope planting with burning - EDQ) on soil and water losses by water erosion and to compare them with losses in native forest (FN), pasture (PP) and bare soil (SD), in a Red Latosol (LV) and Red-Yellow Latosol (LVA), indicating which is the most critical period in relation to water erosion during the cycle of Eucalyptus forest plantation. The study was carried out in two places: Belo Oriente (LVA) and Guanh\ue3es (LV), located in 'Doce' River Valley, central and eastern region of Minas Gerais State, Brazil. Except for the SD system in the LVA, the average soil losses were below the limit of soil loss tolerance, in such regions, which are 11.22 Mg ha-1 yr-1 for the LV and 7.17 Mg ha-1 yr-1 for the LVA. The water losses in the eucalyptus systems were lower in the contour planting, in the LVA. In the eucalyptus systems, the periods immediately after planting showed the greatest soil and water losses with reduction at the final period. On the other hand, in the LVA, the bare soil and native forest systems increased water losses with the advancing of the evaluation period, indicating adequacy of Eucalyptus systems

Sistemas de manejo em plantios florestais de eucalipto e perdas de solo e água na região do Vale do Rio Doce, MG

Water erosion is the main responsible for decreasing the productive capacity of soils under forest plantations and it changes the amount and the quality of water in sub-basins. Thus, this work aimed to evaluate the influence of management systems adopted in Eucalyptus forest plantations (eucalyptus in contour planting - EN, eucalyptus up and downslope planting - ED, and eucalyptus up and downslope planting with burning - EDQ) on soil and water losses by water erosion and to compare them with losses in native forest (FN), pasture (PP) and bare soil (SD), in a Red Latosol (LV) and Red-Yellow Latosol (LVA), indicating which is the most critical period in relation to water erosion during the cycle of Eucalyptus forest plantation. The study was carried out in two places: Belo Oriente (LVA) and Guanhães (LV), located in ‘Doce’ River Valley, central and eastern region of Minas Gerais State, Brazil. Except for the SD system in the LVA, the average soil losses were below the limit of soil loss tolerance, in such regions, which are 11.22 Mg ha-1 yr-1 for the LV and 7.17 Mg ha-1 yr-1 for the LVA. The water losses in the eucalyptus systems were lower in the contour planting, in the LVA. In the eucalyptus systems, the periods immediately after planting showed the greatest soil and water losses with reduction at the final period. On the other hand, in the LVA, the bare soil and native forest systems increased water losses with the advancing of the evaluation period, indicating adequacy of Eucalyptus systems.A erosão hídrica é a principal responsável pela perda da capacidade produtiva dos solos sob florestas plantadas e alteração da quantidade e qualidade da água em sub-bacias. Assim, este trabalho objetivou avaliar a influência dos sistemas de manejo adotados nos plantios florestais com eucalipto (eucalipto em nível - EN, eucalipto em desnível - ED e eucalipto em desnível com queima - EDQ) sobre as perdas de solo e água por erosão hídrica em relação às perdas em floresta nativa (FN), pastagem (PP) e solo descoberto (SD), num Latossolo Vermelho (LV) e Latossolo Vermelho-Amarelo (LVA), e indicar qual o período mais crítico no manejo do solo, em relação à erosão hídrica, durante o ciclo de cultivo do eucalipto. O estudo foi conduzido em dois municípios: Belo Oriente (LVA) e Guanhães (LV), situados no Vale do Rio Doce, região Centro-Leste do estado de Minas Gerais. Com exceção do sistema SD no LVA, as perdas de solo foram abaixo do limite de tolerância admissível para essas classes de solos, nestas regiões, que são de 11,22 Mg ha-1 ano-1 no LV e de 7,17 Mg ha-1 ano-1 para o LVA. As perdas de água nos sistemas com eucalipto foram menores no plantio em nível, no LVA. Nos sistemas com eucalipto, os períodos iniciais após o plantio apresentam as maiores perdas de solo e água com redução ao final do ciclo. Por outro lado, no LVA os sistemas com solo descoberto e floresta nativa apresentaram aumento das perdas de água com o decorrer do tempo avaliado, indicando adequação dos sistemas com eucalipto

Estabilidade de agregados em solos cultivados com eucalipto

The objective of this work was to evaluate the aggregate stability of tropical soils under eucalyptus plantation and native vegetation, and assess the relationships between aggregate stability and some soil chemical and physical properties. Argisols, Cambisol, Latosols and Plinthosol within three eucalyptus-cultivated regions, in the states of Espírito Santo, Rio Grande do Sul and Minas Gerais, Brazil, were studied. For each region, soils under native vegetation were compared to those under minimum tillage with eucalyptus cultivation. The aggregate stability was measured using the high-energy moisture characteristic (HEMC) technique, i.e., the moisture release curve at very low suctions. This method compares the resistance of aggregates to slaking on a relative scale from zero to one. Thus, the aggregate stability from different soils and management practices can be directly compared. The aggregate stability ratio was greater than 50% for all soils, which shows that the aggregate stability index is high, both in eucalyptus and native vegetation areas. This suggests that soil management adopted for eucalyptus cultivation does not substantially modify this property. In these soils, the aggregate stability ratio does not show a good relationship with clay or soil organic matter contents. However, soil organic matter shows a positive relationship with clay content and cation exchange capacity.O objetivo deste trabalho foi avaliar a estabilidade de agregados, em solos tropicais sob cultivo de eucalipto e vegetação nativa, e avaliar as relações entre a estabilidade de agregados e alguns atributos químicos e físicos do solo. Foram estudados Argissolos, Cambissolo, Latossolos e Plintossolo dentro de três regiões com cultivo de eucalipto, nos estados do Espírito Santo, Rio Grande do Sul e Minas Gerais. Para cada região, os solos com vegetação nativa foram comparados aos solos com preparo mínimo sob plantio de eucalipto. A estabilidade de agregados foi determinada por meio da técnica da curva característica da umidade em alta energia (HEMC), isto é, a curva de retenção de umidade na sucção muito baixa. Este método compara a resistência dos agregados à quebra em uma escala relativa de zero a um. Deste modo, a estabilidade de agregado em diferentes solos e práticas de manejo pode ser diretamente comparada. A razão de estabilidade de agregados foi maior que 50% em todos os solos estudados o que indica que o índice de estabilidade de agregados é alto tanto nas áreas com cultivo de eucalipto quanto naquelas com vegetação nativa. Isto sugere que o manejo do solo adotado para o eucalipto não modifica substancialmente este atributo. Nesses solos, a razão de estabilidade de agregados não mostra boa correlação com o conteúdo de argila ou de matéria orgânica. Entretanto, a matéria orgânica do solo mostra uma positiva correlação com o conteúdo de argila e com a capacidade de troca de cátion

INFLUÊNCIA ANTRÓPICA E ATRIBUTOS DE SOLO: INTER-RELAÇÕES EM AMBIENTES DE VOÇOROCAS NA MESORREGIÃO CAMPOS DAS VERTENTES, MG

O estado de Minas Gerais é dividido em doze mesorregiões sendo o Campos das Vertentes uma delas, localizada na porção setentrional da Bacia do Alto Rio Grande, a segunda maior bacia hidrográfica do estado, que abastece os reservatórios de Furnas, Itutinga, Camargos e Funil, entre outros. O Alto do Rio Grande foi a primeira área de Minas Gerais a ser ocupada pelos colonizadores portugueses no fim do século XVII, onde o município de Nazareno se destaca pela presença de áreas degradadas devido ao mau uso do solo. A mineração foi a principal atividade econômica da bacia durante séculos e, ainda hoje, diversos recursos minerais encontram-se em exploração gerando sérios problemas ambientais (SOARES et al., 1994), notadamente no que se refere à principal forma de degradação do solo, a erosão hídrica

Predicting runoff risks by digital soil mapping

Digital soil mapping (DSM) permits continuous mapping soil types and properties through raster formats considering variation within soil class, in contrast to the traditional mapping that only considers spatial variation of soils at the boundaries of delineated polygons. The objective of this study was to compare the performance of SoLIM (Soil Land Inference Model) for two sets of environmental variables on digital mapping of saturated hydraulic conductivity and solum depth (A + B horizons) and to apply the best model on runoff risk evaluation. The study was done in the Posses watershed, MG, Brazil, and SoLIM was applied for the following sets of co-variables: 1) terrain attributes (AT): slope, plan curvature, elevation and topographic wetness index. 2) Geomorphons and terrain attributes (GEOM): slope, plan curvature, elevation and topographic wetness index combined with geomorphons. The most precise methodology was applied to predict runoff areas risk through the Wetness Index based on contribution area, solum depth, and saturated hydraulic conductivity. GEOM was the best set of co-variables for both properties, so this was the DSM model used to predict the runoff risk. The runoff risk showed that the critical months are from November to March. The new way to classify the landscape to use on DSM was demonstrated to be an efficient tool with which to model process that occurs on watersheds and can be used to forecast the runoff risk

Water sufficiency for cacao production in the Sierra Nevada de Santa Marta (SNSM) region, Colombia

Study region: Sierra Nevada de Santa Marta (SNSM) region of Colombia. Study focus: This research was conducted as a case study to generate relevant, quantitative information to support cacao farmer decision-making processes concerning water management in the SNSM. It involved the development and evaluation of a spatial dataset of precipitation and temperature, integration of digital soil mapping with a modification of the Thornthwaite and Mather water balance model, and finally an assessment of water sufficiency for cacao production. We elaborated site-specific and spatially-distributed analyses to generate information that will be shared with technicians who assist cacao growers in the SNSM. New hydrological insights for the region: Under the climate conditions for the analysis period (1989–2018), rainfall was not enough to prevent cacao yield losses for 10 out of the 27 farms evaluated. The location of farms in two departments with contrasting climate conditions showed the importance of spatial analysis of water availability when providing recommendations of management practices to cacao growers. The results revealed that farms facing less frequent water stress are characterized by higher rainfalls and lower temperatures, soils that contain more organic matter, and are located at higher elevations with steeper slopes. Temporally, water stress is highest in the months February-August, with special interest in March-April as the dry season ends and July-August just before the peak rainy season