Indicadores de qualidade de Latossolo relacionados à degradação de pastagens

The objective of this work was to select the soil quality indicators more related to pasture degradation and to establish the limits of the different degradation levels using these indicators. Five pasture areas on an Oxisol were selected in the medium third of the slope, with different levels of visual degradation,considering the following variables: loss of vigor, presence of weeds, exposed bare soil, and erosion. Soil cover was evaluated, and soil samples were collected at the 0.00–0.05, 0.05–0.10, and 0.10–0.20-m soil depths, for physical, chemical, and organic matter analyses. Differently from the visual classification, the cluster analysis of the cover variables only indicated two degradation levels: low to moderate and high to very high, with classification percentage above 87% in the discriminant analysis, in which bare soil was the most assertive variable for discriminating the degradation levels. Light organic matter and the Ca+Mg component were the indicators most related to pasture degradation indices at 0.00–0.05 m; while potassium content was the indicator most related to those indices at the 0.05–0.10 and 0.10–0.20-m soil depths.O objetivo deste trabalho foi selecionar os indicadores de qualidade de solo mais relacionados à degradação de pastagens, e estabelecer os limites de diferentes níveis de degradação a partir desses indicadores. Cinco pastagens sobre Latossolo Vermelho-Amarelo foram selecionadas, em terço médio da encosta, com diferentes níveis visuais de degradação, tendo-se considerado as variáveis: perda de vigor, presença de espécies espontâneas, solo exposto e erosão. Avaliou-se a cobertura do solo, e coletaram-se amostras nas profundidades de 0,00–0,05, 0,05–0,10 e 0,10–0,20 m, para as análises físicas, químicas e de matéria orgânica. Diferentemente da classificação visual, a análise de grupamento das variáveis de cobertura indicou apenas dois níveis de degradação: de baixo a moderado e de alto a muito alto, com percentual de classificações corretas acima de 87% na análise discriminante, em que o solo exposto foi a variável mais assertiva para discriminar os níveis de degradação. A matéria orgânica leve e o componente Ca+Mg foram os indicadores de qualidade mais relacionados aos índices de degradação de pastagens à profundidade de 0,00–0,05 m; enquanto o teor de potássio foi o indicador mais relacionado aos índices às profundidades de 0,05–0,10 e 0,10–0,20 m

Panorama atual e potencial de aplicação da abordagem dos serviços ecossistêmicos do solo no Brasil

Human pressure on ecosystems has undesirable impacts on human well-being. After the Millennium Project, much interdisciplinary research has been developed worldwide aiming to understand these impacts on ecosystem flows and processes, and to learn about the costs and the benefits of ecosystem services for production. Soil provides many ecosystem services, since its multi-functionality is the basis for food production, water filtration, nutrient cycling, and other goods essential to life. This article presents the main concepts and classifications of soil ecosystem services and of its functions; the indicators and the methods for assessment, modeling, and valuation of ecosystem services; some recent applications to assess and evaluate impacts of agricultural management practices on soil ecosystem services; as well as challenges and opportunities for research and for development of public policies related to agro-environmental sustainability in Brazil. Although the role of soil in supplying ecosystem services is yet undervalued, scientists are gradually recognizing soil processes and functions as fundamental to assess ecosystem services and the effects of land use and management on them. Interdisciplinary approaches to integrate science and public policies are necessary to build governance based on ecosystem services.A pressão humana sobre os serviços ecossistêmicos tem resultado em impactos indesejáveis sobre o bem-estar humano. Com o Projeto Millennium, várias pesquisas interdisciplinares têm sido desenvolvidas em todo o mundo com o objetivo de entender esses impactos sobre os fluxos e os processos dos ecossistemas e internalizar os custos e os benefícios dos serviços ecossistêmicos para a produção. O solo fornece muitos serviços ecossistêmicos, uma vez que sua multifuncionalidade é a base para a produção de alimentos, filtração de água, ciclagem de nutrientes e outros bens essenciais à vida. Este artigo apresenta os principais conceitos e classificações dos serviços ecossistêmicos do solo e de suas funções; os indicadores e os métodos de avaliação, modelagem e valoração dos serviços ecossistêmicos; algumas aplicações recentes para avaliar impactos de práticas de manejo agrícola sobre os serviços ecossistêmicos do solo; bem como os desafios e as oportunidades para a pesquisa e para o desenvolvimento de políticas públicas relacionadas à sustentabilidade agroambiental no Brasil. Apesar de o papel do solo para prestação de serviços ecossistêmicos ainda ser subestimado, os cientistas têm gradualmente reconhecido os processos e as funções do solo como fundamentais para avaliar os serviços ecossistêmicos e os efeitos do uso e manejo da terra sobre eles. Abordagens interdisciplinares que integrem ciência e políticas públicas são necessárias para construir uma governança com base em serviços ecossistêmicos

Soils Developed on Geomorphic Surfaces in the Mountain Region of the State of Rio de Janeiro

<div><p>ABSTRACT: The evaluation of soils in representative landscapes constitutes an opportunity to evaluate spatial distribution, discuss formation processes, and apply this knowledge to land use and management. In this sense, from the perspective of an environmentally diversified region, the aim of the present study is to evaluate the occurrence and understand the formation of soils in different geomorphic surfaces of a landscape from a mountain region in the state of Rio de Janeiro. The study was developed in the Pito Aceso microbasin in the municipality of Bom Jardim, composed of narrow valleys and a rugged mountain domain, with elevation between 640 and 1,270 m. In a representative landscape, the geomorphic surfaces were obtained from the slope segments and flow lines. On the geomorphic surfaces, soil profiles were described by their morphological properties, collected, and analyzed to describe the chemical and physical properties of each horizon. Geomorphological aspects and possible variations of the parent material directly affected pedogenesis and led to distinct soil classes in the landscape. Variation in the geomorphic surfaces directs the processes for soil formation under current conditions, as well as the preservation of polygenetic soils. Soils of lower development and with greater participation of the exchangeable cations were identified at the summit (talus deposit) (Neossolo Litólico and Cambissolo Húmico) and toeslope (colluvial-alluvial) (Neossolo Flúvico), whereas more developed soils with lower nutrient content occur in the concave (Argissolos Vermelho and Amarelo) and convex (Latossolo Amarelo) backslope, except for the Argissolo Vermelho-Amarelo in the shoulder, which had high exchangeable cations contents.</p></div

Characterization, agricultural potential, and perspectives for management of light soils in Brazil

Os solos leves ocupam cerca de 8% do território brasileiro e são epecialmente expressivos na nova e na última fronteira agrícola do país: a região de Matopiba, nos estados do Maranhão, do Tocantins, do Piauí e da Bahia, onde representam 20% da área. Esses solos enquadram-se nas classes texturais areia e areia franca ou francoarenosa, até a profundidade de 0,75 m ou mais, e são representados principalmente pelos Neossolos Quartzarênicos e, em parte, por Latossolos e Argissolos. O entendimento do funcionamento desses solos depende do estabelecimento de critérios distintivos sobre: dinâmica da matéria orgânica; teor e mineralogia da fração argila; teores de areia grossa e de areia total, em relação aos de areia fina; diâmetro médio da fração areia; e capacidade de retenção de água. Esses critérios podem contribuir para o zoneamento e para o manejo conservacionista e da fertilidade dos solos leves, bem como para estimação de seu potencial agrícola. Sistemas integrados de produção, como os de integração lavoura-pecuária e lavoura-pecuária-floresta, além do plantio direto com rotação de culturas, dos plantios florestais mistos com espécies leguminosas, e do uso de adubos verdes e cultivos de cobertura, são relevantes para o manejo adequado desses solos. O objetivo deste artigo de revisão foi caracterizar os solos leves e apontar os principais desafios em relação a seu potencial agrícola, a seu manejo e conservação e sua fertilidade, frente à expansão e à consolidação da nova fronteira agrícola.Light soils occupy 8% of the Brazilian territory and are especially expressive in the new and last agricultural frontier in Brazil: the Matopiba region – in the states of Maranhão, Tocantins, Piauí, and Bahia –, where they represent 20% of the area. These soils fit into the textural classes of sand, loamy sand, and sandy loam, down to 0.75-m soil depth or deeper, and they are mainly represented by Entisols (Quartzipsamments), and partly by Oxisols and Ultisols. The understanding of soil functioning depends on the establishment of distinguishing criteria for: organic matter dynamics; content and mineralogy of the clay fraction; coarse sand and total sand contents, in relation to those of fine sand; mean diameter of the sand fraction; and water retention capacity. These criteria can contribute for the zoning and for the conservationist and fertility management of light soils, as well as for the estimation of their agricultural potential. Integrated production systems, such as, crop-livestock and crop-livestock-forestry integration, besides no-tillage with crop rotation, mixed forestry planting with legumes, and the use of green manure and cover crops, are relevant for the proper management of these soils. The objective of this review was to characterize light soils and to highlight the main challenges regarding their agricultural potential and their conservation and fertility managements, in face of the expansion and consolidation of the new Brazilian agricultural frontier

Soils developed on geomorphic surfaces in the mountain region of the State of Rio de Janeiro.

The evaluation of soils in representative landscapes constitutes an opportunity to evaluate spatial distribution, discuss formation processes, and apply this knowledge to land use and management. In this sense, from the perspective of an environmentally diversified region, the aim of the present study is to evaluate the occurrence and understand the formation of soils in different geomorphic surfaces of a landscape from a mountain region in the state of Rio de Janeiro. The study was developed in the Pito Aceso microbasin in the municipality of Bom Jardim, composed of narrow valleys and a rugged mountain domain, with elevation between 640 and 1,270 m. In a representative landscape, the geomorphic surfaces were obtained from the slope segments and flow lines. On the geomorphic surfaces, soil profiles were described by their morphological properties, collected, and analyzed to describe the chemical and physical properties of each horizon. Geomorphological aspects and possible variations of the parent material directly affected pedogenesis and led to distinct soil classes in the landscape. Variation in the geomorphic surfaces directs the processes for soil formation under current conditions, as well as the preservation of polygenetic soils. Soils of lower development and with greater participation of the exchangeable cations were identified at the summit (talus deposit) (Neossolo Litólico and Cambissolo Húmico) and toeslope (colluvial-alluvial) (Neossolo Flúvico), whereas more developed soils with lower nutrient content occur in the concave (Argissolos Vermelho and Amarelo) and convex (Latossolo Amarelo) backslope, except for the Argissolo Vermelho-Amarelo in the shoulder, which had high exchangeable cations contents.Made available in DSpace on 2017-11-27T23:33:59Z (GMT). No. of bitstreams: 1 2017055.pdf: 799431 bytes, checksum: 0cb5804ec26ec0d84c1295016754081d (MD5) Previous issue date: 2017-11-27bitstream/item/167548/1/2017-055.pd