Érika F. M. Pinheiro

Spatial variability of soil carbon stock in the Urucu river basin, Central Amazon-Brazil

The Amazon Forest plays a major role in C sequestration and release. However, few regional estimates of soil organic carbon (SOC) stock in this ecoregion exist. One of the barriers to improve SOC estimates is the lack of recent soil data at high spatial resolution, which hampers the application of new methods for mapping SOC stock. The aims of this work were: (i) to quantify SOC stock under undisturbed vegetation for the 0-30 and the 0-100 cm under Amazon Forest; (ii) to correlate the SOC stock with soil mapping units and relief attributes and (iii) to evaluate three geostatistical techniques to generate maps of SOC stock (ordinary, isotopic and heterotopic cokriging). The study site is located in the Central region of Amazon State, Brazil. The soil survey covered the study site that has an area of 80 km(2) and resulted in a 1:10,000 soil map. It consisted of 315 field observations (96 complete soil profiles and 219 boreholes). SOC stock was calculated by summing C stocks by horizon, determined as a product of BD, SOC and the horizon thickness. For each one of the 315 soil observations, relief attributes were derived from a topographic map to understand SOC dynamics. The SOC stocks across 30 and 100 cm soil depth were 3.28 and 7.32 kg C m(-2), respectively, which is, 34 and 16%, lower than other studies. The SOC stock is higher in soils developed in relief forms exhibiting well-drained soils, which are covered by Upland Dense Tropical Rainforest. Only SOC stock in the upper 100 cm exhibited spatial dependence allowing the generation of spatial variability maps based on spatial (co)-regionalization. The CTI was inversely correlated with SOC stock and was the only auxiliary variable feasible to be used in cokriging interpolation. The heterotopic cokriging presented the best performance for mapping SOC stock.

Substâncias húmicas e relação com atributos edáficos

Este trabalho teve como objetivo caracterizar a distribuicao das substâncias humicas (acidos fulvicos livres, acidos humicos, acidos fulvicos e humina) e atributos edaficos em perfis de solos de diferentes regioes do Brasil, que foram objeto de estudos de reunioes de correlacao e levantamentos de solos realizados pela Embrapa e outras instituicoes. As amostras foram selecionadas e fracionadas seguindo conceitos da IHSS. A fracao humina apresentou os maiores valores de C em todos os perfis, seguida pelos acidos fulvicos livres. Nos perfis em ambientes com altitudes elevadas o clima (Cwa, Cfb, Cwb) favoreceu a formacao dos acidos fulvicos livres. Quanto as propriedades quimicas, em ambos os horizontes foram verificados coeficientes de correlacao positiva entre o hidrogenio e o conteudo de carbono orgânico, r=0,58* e r=0,83**, para os horizontes A e B, respectivamente. Dentre as substâncias humicas a de melhor correlacao com o conteudo de carbono orgânico foi a fracao humina, com r=0,89** e r=0,91** para os horizontes A e B, respectivamente. Foi observada correlacao positiva (p<0,05) entre a areia grossa e os C-FAF, C-FAH, C-HUM e a relacao C-EA:C-HUM, nos horizontes A, indicando que a textura mais arenosa de alguns horizontes superficiais favorece a formacao destas substâncias humicas. O teor de C nos horizontes superficiais e subsuperficiais e a distribuicao das substâncias humicas variaram com a pedogenese e a altitude.

Prediction of Soil Physical and Chemical Properties by Visible and Near-Infrared Diffuse Reflectance Spectroscopy in the Central Amazon

Visible and near-infrared diffuse reflectance spectroscopy (VIS-NIR) has shown levels of accuracy comparable to conventional laboratory methods for estimating soil properties. Soil chemical and physical properties have been predicted by reflectance spectroscopy successfully on subtropical and temperate soils, whereas soils from tropical agro-forest regions have received less attention, especially those from tropical rainforests. A spectral characterization provides a proficient pathway for soil characterization. The first step in this process is to develop a comprehensive VIS-NIR soil library of multiple key soil properties to be used in future soil surveys. This paper presents the first VIS-NIR soil library for a remote region in the Central Amazon. We evaluated the performance of VIS-NIR for the prediction of soil properties in the Central Amazon, Brazil. Soil properties measured and predicted were: pH, Ca, Mg, Al, H, H+Al, P, organic C (SOC), sum of bases, cation exchange capacity (CEC), percentage of base saturation (V), Al saturation (m), clay, sand, silt, silt/clay (S/C), and degree of flocculation. Soil samples were scanned in the laboratory in the VIS-NIR range (350–2500 nm), and forty-one pre-processing methods were tested to improve predictions. Clay content was predicted with the highest accuracy, followed by SOC. Sand, S/C, H, Al, H+Al, CEC, m and V predictions were reasonably good. The other soil properties were poorly predicted. Among the soil properties predicted well, SOC is one of the critical soil indicators in the global carbon cycle. Besides the soil property of interest, the landscape position, soil order and depth influenced in the model performance. For silt content, pH and S/C, the model performed better in well-drained soils, whereas for SOC best predictions were obtained in poorly drained soils. The association of VIS-NIR spectral data to landforms, vegetation classes, and soil types demonstrate potential for soil characterization.

The Meta Soil Model: An Integrative Multi-model Framework for Soil Security

The profound human-centric dominance in the Anthropocene has created changes in land use, biomes, climate, food networks, economies, and social communities, which in turn have impacted global resources, such as food, energy, and water, as well as the soils, that humanity and other terrestrial life-forms depend on for survival. We posit that a new integrative science is needed to support global soil security that facilitates improved soil synthesis of data, knowledge, understanding, experiences, beliefs, values, and actions related to soils considering multiple perspective dimensions, such as soil-environment, soil-politics, and soil-human. Integrative soil security – a new term we coin in this paper – is based on (i) integration of individual and collective human needs, uses, values, beliefs, and perceptions of soils coalesced with (ii) quantitative knowledge of soils derived through empirical observation and quantitative analysis as well as (iii) systems that soils are embedded in (e.g., economic, political, social, and legal systems). We propose a Meta Soil Model (MSM) that is rooted in integral theory and integral ecology as the foundation for a new integral soil security with cognizance as the key integrator. We define an MSM as an integrative, multi-model framework to assess soil security within the context of regional and global human-environmental interactions. The MSM fosters enactment for securing soils rooted in inter-, trans-, and post-(integral) disciplinary thinking and allows to diagnose integration gaps, such as the values and beliefs people hold about soils and scientist’s observations, data, maps, and models of soils, ultimately constraining global soil security.

Soil Carbon Stock and Particle Size Fractions in the Central Amazon Predicted from Remotely Sensed Relief, Multispectral and Radar Data

Soils from the remote areas of the Amazon Rainforest in Brazil are poorly mapped due to the presence of dense forest and lack of access routes. The use of covariates derived from multispectral and radar remote sensors allows mapping large areas and has the potential to improve the accuracy of soil attribute maps. The objectives of this study were to: (a) evaluate the addition of relief, and vegetation covariates derived from multispectral images with distinct spatial and spectral resolutions (Landsat 8 and RapidEye) and L-band radar (ALOS PALSAR) for the prediction of soil organic carbon stock (CS) and particle size fractions; and (b) evaluate the performance of four geostatistical methods to map these soil properties. Overall, the results show that, even under forest coverage, the Normalized Difference Vegetation Index (NDVI) and ALOS PALSAR backscattering coefficient improved the accuracy of CS and subsurface clay content predictions. The NDVI derived from RapidEye sensor improved the prediction of CS using isotopic cokriging, while the NDVI derived from Landsat 8 and backscattering coefficient were selected to predict clay content at the subsurface using regression kriging (RK). The relative improvement of applying cokriging and RK over ordinary kriging were lower than 10%, indicating that further analyses are necessary to connect soil proxies (vegetation and relief types) with soil attributes.

Integrating New Perspectives to Address Global Soil Security: Ideas from Integral Ecology

Global soil security is complex, encompassing technical, socioeconomic, and political issues and people’s beliefs and values. Our thesis is that global soil security and the soil health crisis we face today are due to a lack of awareness and understanding of prominent values and benefits soils provide to sustain humanity. In this paper, we use the integral lens to explore global soil security. The integral ecology model uses four interconnected perspectives (the individual-interior, collective-interior, individual-exterior, and collective-exterior) to study wicked environmental issues. We assert that cognizance is the key integrator to bring forth awareness, knowledge, and understanding within and across the four equally important perspectives. It has profound significance for global soil security because it reveals the underlying causes that jeopardize the security of soils and identifies chasms that constrain the sustainability of soil ecosystems. Cognizance is the (i) awareness and perceptions held by individuals and people (interior perspectives), (ii) the facts, knowledge, and understanding of external phenomena (exterior perspectives), and (iii) their interactive effects (i.e., integration across all four perspectives of the integral map). Importantly, cognizance is preceding any other dimension of soil security (connection, codification, capital, condition, and capability). Reductionist approaches that are one-sided (e.g., “soil science will fix the global soil security crisis”) ignore people’s beliefs and values and are non-cognizant of interconnected perspectives are doomed for failure. Ecological awareness is composed of exterior “scientist/observer/3rd person” qualities and interior “people/subjective” qualities. To achieve global soil security, it is necessary to grow ecological awareness evoking to value, care for, and secure the natural world including soils. Recognizing the significance of global soil security is closely linked to moral values and ethical beliefs people hold relative to soils. These beliefs provide the motivation and appropriate actions needed within cultural, social, environmental, and institutional contexts to secure soils.

Avaliação do potencial de uso de biofertilizante de esterco bovino resultante do sistema de manejo orgânico e convencional da produção de leite.

Objetivou-se avaliar o potencial de utilizacao como adubo orgânico do biofertilizante, resultante da biodigestao anaerobica de dejetos de bovinos de leite, sob sistema orgânico (DBSO) e convencional (DBSC) de producao. Utilizaram-se oito prototipos de biodigestores abastecidos com os dejetos de bovinos. O delineamento experimental foi o inteiramente casualizado, com 4 repeticoes para cada tratamento. Apos o processo de biodigestao anaerobica foram realizadas analises quimicas, fisico-quimicas e biologicas, de acordo com a Resolucao CONAMA 375/06. Os biofertilizantes oriundos de DBSO e DBSC apresentaram um teor de carbono minimo para serem considerados fertilizantes orgânicos, com valores de 392,4 e 411,9 g kg-1, respectivamente. A biodigestao anaerobica elevou o pH e reduziu a condutividade eletrica (CE) no material efluente, apresentando diferenca estatistica entre os dois tratamentos. Os teores de Mg, K e Fe foram superiores nos biofertilizantes de DBSO e os de Mn, Cu, Zn e Ba foram maiores nos biofertilizantes de DBSC. No biofertilizante oriundo de DBSC o teor de Cd ficou acima do permitido por lei para fertilizantes orgânicos. Portanto, os sistemas de producao de leite influenciam nas caracteristicas quimicas e fisico-quimicas do biofertilizante produzido. O esterco produzido por bovinos sob sistema orgânico de producao de leite demonstrou maior potencial de uso como adubo orgânico quando comparado ao esterco oriundo do manejo convencional.

Avaliação do Tratamento da Água Residuária da Suinocultura Utilizando Filtro Orgânico Constituído de Bagaço de Cana-de-Açúcar

O bagaco de cana-de-acucar mostrou-se promissor na retencao de poluentes das aguas residuarias, assim, o objetivo deste trabalho foi avaliar a capacidade desse residuo em reter solidos e metais da agua residuaria da suinocultura (ARS). O material foi acondicionando em uma coluna de filtracao construida com garrafas PET e preenchida com o bagaco de cana-de-acucar triturado, constituindo o filtro orgânico. Durante a operacao foram filtrados 50 L de ARS, desse efluente avaliou-se o pH, a condutividade eletrica, a concentracao de solidos totais e volateis, os teores totais de Ca, Mg, Cu, Zn, Mn, Fe e Al. Apos o tratamento, observou-se o aumento do pH e uma baixa reducao da condutividade eletrica da ARS filtrada. A melhor eficiencia do filtro orgânico foi entre 30 e 40 L de efluente filtrado, nesse intervalo foi possivel obter retencao de solidos totais e volateis maior que 40% e retencao de Cu, Zn e Mn acima de 99%. O Al foi o elemento menos retido no filtro, com remocao entre 13 e 19% no intervalo de 30 e 40 L de ARS filtrada.

Emissões de N2O em Solos sob Cultivo de Cana-de-Açúcar no bioma Mata Atlântica: Efeito dos Sistemas de Colheita e da Adubação com Vinhaça

A conversao de areas sob vegetacao natural para areas agricolas e uma das maiores fontes de emissao de gases de efeito estufa (GEE). O motivo do aumento da emissao de GEE nao e somente devido a perda da biomassa vegetal decorrente da queima e preparo das areas para o plantio, mas tambem pela maior decomposicao da materia orgânica do solo (MOS) decorrente das praticas de manejo agricola (fertilizacao, irrigacao, queima de residuos culturais e mecanizacao). O objetivo deste estudo foi quantificar o fluxo do gas oxido nitroso (N2O) em duas areas tradicionais de cultivo de cana-de-acucar, uma com diferentes manejos da palhada perante a colheita (cana queimada e cana crua) em Linhares (ES) e outra area com diferentes manejos de adubacao (com e sem aplicacao de vinhaca) em Campos dos Goytacazes (RJ), ambas inseridas no bioma Mata Atlântica do Brasil. O experimento conduzido em Linhares, avaliado em outubro 2007 na area experimental na Usina LAGRISA teve como tratamentos: corte da cana apos a queima da palhada (cana queimada) e corte da cana sem a queima da palhada (cana crua) e com distribuicao da palha na superficie do solo. Ja no experimento conduzido em Campos dos Goytacazes, avaliado em julho de 2008 os tratamentos consistiram de cana sem adubacao de vinhaca e cana com adubacao de vinhaca (dose unica de 150 m3 ha-1). As avaliacoes das emissoes de N2O foram realizadas com câmaras estaticas com seis repeticoes por tratamento em ambas as areas de estudo. Os valores de fluxo de N2O em Linhares nao foram elevados, apresentando uma media semanal de 1,91 e 2,87 µg m-2 h-1 para os sistemas cana queimada e cana crua, respectivamente. A maior perda de N2O para a atmosfera ocorreu de forma decrescente a partir de dois dias apos a adubacao nitrogenada aliada a cobertura dos residuos no sistema cana crua. Ja na area experimental de Campos dos Goytacazes, a aplicacao de vinhaca potencializou o fluxo de N2O apresentando valores elevados (195 µg m-2 h-1) cinco horas apos a adubacao. O tratamento sem aplicacao de vinhaca apresentou valores de fluxo proximos a zero (0,4 µg m-2 h-1), na mesma coleta. Apos quatro dias da adubacao com vinhaca nao houve mais diferenca no fluxo de N2O entre os tratamentos avaliados. A quantidade de materia orgânica facilmente assimilavel para os microrganismos do solo, o aumento da umidade do solo devido a adicao da vinhaca e a precipitacao ocorrida logo apos a adubacao foram, provavelmente, as variaveis mais importantes no controle e na magnitude das emissoes de N2O.

Applying the Meta Soil Model: The Complexities of Soil and Water Security in a Permanent Protection Area in Brazil

Soil security denotes freedom from risks of losing a specific or a group of soil functions. This case study in the permanent protection area of Sana river (PPA-Sana), Brazil, addresses the relationship between soil security and water security. It explores the soil function “the provision of clean water and its storage, as well as filtering the contamination of water ways.” The study also presents a formal way to put soil security into practice applying the meta soil model. Meta soil modeling is built on integral theory that facilitates to understand the complexity of soil, water, and other securities. The soil and water securities in the PPA-Sana are interconnected and at risk. Specifically, one of the main problems is the discharge of soil sediments in the rivers as a consequence of soil erosion. Soil erosion and compaction constrain soil and water security, and these were monitored and mapped in order to provide support for policy interventions. However, our findings suggest that producing better soil maps and more monitoring are not enough to improve soil and water security. On the contrary, awareness building, creating trust among stakeholders, and better integration among quadrants of the integral model would lead to an enhancement of soil and water security. In essence, cognizance (the sixth dimension of soil and other securities) is profoundly important to allow integration of human and biophysical system dimensions.