Eduardo Guimarães Couto

Relationships between soil hydrology and forest structure and composition in the southern Brazilian Amazon

Abstract Question: Is soil hydrology an important niche-based driver of biodiversity in tropical forests? More specifically, we asked whether seasonal dynamics in soil water regime contributed to vegetation partitioning into distinct forest types. Location: Tropical rain forest in northwestern Mato Grosso, Brazil. Methods: We investigated the distribution of trees and lianas ≥ 1 cm DBH in ten transects that crossed distinct hydrological transitions. Soil water content and depth to water table were measured regularly over a 13-month period. Results: A detrended correspondence analysis (DCA) of 20 dominant species and structural attributes in 10 × 10 m subplots segregated three major forest types: (1) high-statured upland forest with intermediate stem density, (2) medium-statured forest dominated by palms, and (3) low-statured campinarana forest with high stem density. During the rainy season and transition into the dry season, distinct characteristics of the soil water regime (i.e. hydro-indicators) were closely associated with each vegetation community. Stand structural attributes and hydro-indicators were statistically different among forest types. Conclusions: Some upland species appeared intolerant of anaerobic conditions as they were not present in palm and campinarana sites, which experienced prolonged periods of saturation at the soil surface. A shallow impermeable layer restricted rooting depth in the campinarana community, which could heighten drought stress during the dry season. The only vegetation able to persist in campinarana sites were short-statured trees that appear to be well-adapted to the dual extremes of inundation and drought. Nomenclature: Ribeiro et al. (1999).

Biochar decreases dissolved organic carbon but not nitrate leaching in relation to vinasse application in a Brazilian sugarcane soil

OBJECTIVES Sugarcane cultivation is associated with catchment-wide impacts related to application of vinasse, a nutrient-dense effluent with high eutrophication potential. We evaluated the potential for biochar (charcoal produced from pyrolyzed filtercake) to mitigate carbon and nutrient leaching in a cultivated Brazilian Ferralsol after vinasse application. METHODS Twelve soil columns (soil alone [S], soil with vinasse [SV], soil with vinasse and biochar [SVB], and soil with biochar [SB]) were flushed with water and then treated with water or vinasse. Samples collected via vacuum filtration were examined via UV-Vis and fluorescence spectroscopy. RESULTS Biochar attenuated dissolved organic carbon (DOC) leaching in soil (S vs. SB) as well as in relation to vinasse application (SV vs. SVB). Biochar-amended soil preferentially retained high-molecular weight, humic-like DOC species, as revealed by fluorescence spectroscopy and optical indices, but did not retain low-weight amino acid-like species. Vinasse application also increased total NO3(-) flux, which may have been exacerbated by biochar co-application. CONCLUSIONS Vinasse treatment strongly affects carbon and NO3(-) fluxes in this tropical soil. Biochar attenuated DOC leaching, likely through stabilization of complex compounds already present in soil, but did not lessen NO3(-) fluxes. Thus, biochar amendments in vinasse application areas may decrease carbon leaching.

Litterfall production and fluvial export in headwater catchments of the southern Amazon

Resolving the carbon (C) balance in the Amazonian forest depends on an improved quantification of production and losses of particulate C from forested landscapes via stream export. The main goal of this work was to quantify litterfall, the lateral movement of litter, and the export of coarse organic particulate matter (>2 mm) in four small watersheds (1-2 ha) under native forest in southern Amazonia near Juruena, Mato Grosso, Brazil (10 ◦ 25 � S, 58 ◦ 46 � W). Mean litterfall production was 11.8 Mg ha −1 y −1 (5.7 Mg C ha −1 y −1 ). Litterfall showed strong seasonality, with the highest deposition in the driest months of the year. About two times more C per month was deposited on the forest floor during the 6-mo dry season (0.65 Mg C ha −1 mo −1 ) compared with the rainy season (0.3 Mg C ha −1 mo −1 ). The measured C concentration of the litterfall samples was significantly greater in the dry season than in the rainy season (49% vs. 46%). The lateral movement of litter increased from the plateau (upper landscape position) towards the riparian zone. However, the trend in C concentration of laterally transported litter samples was the opposite, being highest on the plateau (44%) and lowest in the riparian zone (42%). Stream-water exports of particulate C were positively correlated with streamflow, increasing in the rainiest months. The export of particulate C in streamflow was found to be very small (less than 1%) in relation to the amount of litterfall produced.

Environmental footprints show China and Europe’s evolving resource appropriation for soybean production in Mato Grosso, Brazil

Mato Grosso has become the center of Brazil’s soybean industry, with production located across an agricultural frontier expanding into savanna and rainforest biomes. We present environmental footprints of soybean production in Mato Grosso and resource flows accompanying exports to China and Europe for the 2000s using five indicators: deforestation, land footprint (LF), carbon footprint (CF), water footprint (WF), and nutrient footprints. Soybean production was associated with 65% of the state’s deforestation, and 14–17% of total Brazilian land use change carbon emissions. The decade showed two distinct production systems illustrated by resources used in the first and second half of the decade. Deforestation and carbon footprint declined 70% while land, water, and nutrient footprints increased almost 30% between the two periods. These differences coincided with a shift in Mato Grosso’s export destination. Between 2006 and 2010, China surpassed Europe in soybean imports when production was associated with 97 m 2 deforestation yr �1 ton �1 of soybean, a LF of 0.34 ha yr �1 ton �1 , a carbon footprint of 4.6 ton CO2eq yr �1 ton �1 , a WF of 1908 m 3 yr �1 ton �1 , and virtual phosphorous and potassium of 5.0 kg P yr �1 ton �1 and 0.0042 g K yr �1 ton �1 . Mato Grosso constructs soil fertility via

Variabilidade espacial de micronutrientes em solo sob pivô central no sul do Estado de Mato Grosso

RESUMO - Este estudo foi desenvolvido para identificar, caracterizar e comparar a estrutura dadependencia espacial dos micronutrientes boro, cobre, ferro, manganes e zinco soluveis em um LatossoloVermelho-Escuro sob pivo central apos 14 anos de uso intensivo, no sul do Estado de Mato Grosso. Oesquema de amostragem consistiu de coletas de 132 amostras com espacamento regular de 167 m,especialmente idealizado para determinar a variabilidade espacial em distância de ate 1 m. Com excecaodo zinco, o uso intensivo propiciou um aumento significativo nas concentracoes desses nutrientes nacamada mais afetada pelo manejo (0-20 cm), mesmo assim insuficientes para atingir o nivel criticoestabelecido para a regiao. Cerca de 95% das amostras de boro, 75% das amostras de cobre, 95% dasamostras de manganes e 1,5% das amostras de zinco apresentaram valores abaixo do nivel critico,distribuidos diferentemente pelos quadrantes, o que mostra que as praticas de fertilizacao e/ou asoperacoes de preparo de solo nao foram eficientes na distribuicao e homogeneizacao dos fertilizantes.Termos para indexacao: geoestatistica, agricultura de precisao.SPATIAL VARIABILITY OF MICROELEMENTS IN SOIL UNDER CENTER PIVOT IRRIGATIONSYSTEM IN SOUTHERN MATO GROSSO STATE, BRAZILABSTRACT - This study was carried out to identify, characterize and compare spatial structures ofboron, copper, iron, manganese and zinc in a Dark-Red Latosol under crop field intensively managedfor 14 years with a center pivot irrigation system in the Southern Mato Grosso State, Brazil. The soilsampling scheme, consisting of 132 systematic sampling, in which sampling points were located atregular intervals of 167 m, in such a way that it was possible to determine the soil variability at 1 mdistance. The result showed that, with exception of the zinc, the intensive land use increased significantlythe nutrients concentration in the upper layer, however it was insufficient to reach the critical levelestablished for the region. About 95% of boron samples, 75% of copper samples, 95% of manganesesamples and 1.5% of zinc samples presented values below the critical level. These values weredifferently distributed by the quadrants in the center pivot, showed that fertilizers application and /or soiltillage were not efficient to distribute and to homogenize the fertilizers.Index terms: geostatistics, precision agriculture.

Plant functional types and traits as biodiversity indicators for tropical forests: two biogeographically separated case studies including birds, mammals and termites

Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forested landscapes in Sumatra, Indonesia and Mato Grosso, Brazil. Gradient-directed transects (gradsects) were sampled across a range of forested land use mosaics, using a uniform protocol to simultaneously record vegetation (vascular plant species, plant functional types (PFTs) and vegetation structure), vertebrates (birds, mammals) and invertebrates (termites), in addition to measuring site and soil properties, including carbon stocks. At both sites similar correlations were detected between major components of structure (mean canopy height, woody basal area and litter depth) and the diversities of plant species and PFTs. A plant species to PFT ratio [spp.:PFTs] was the best overall predictor of animal diversity, especially termite species richness in Sumatra. To a notable extent vegetation structure also correlated with animal diversity. These surrogates demonstrate generic links between habitat structural elements, carbon stocks and biodiversity. They may also offer practical low-cost indicators for rapid assessment in tropical forest landscapes.

Soil CO2 Dynamics in a Tree Island Soil of the Pantanal: The Role of Soil Water Potential

The Pantanal is a biodiversity hotspot comprised of a mosaic of landforms that differ in vegetative assemblages and flooding dynamics. Tree islands provide refuge for terrestrial fauna during the flooding period and are particularly important to the regional ecosystem structure. Little soil CO2 research has been conducted in this region. We evaluated soil CO2 dynamics in relation to primary controlling environmental parameters (soil temperature and soil water). Soil respiration was computed using the gradient method using in situ infrared gas analyzers to directly measure CO2 concentration within the soil profile. Due to the cost of the sensors and associated equipment, this study was unreplicated. Rather, we focus on the temporal relationships between soil CO2 efflux and related environmental parameters. Soil CO2 efflux during the study averaged 3.53 µmol CO2 m−2 s−1, and was equivalent to an annual soil respiration of 1220 g C m−2 y−1. This efflux value, integrated over a year, is comparable to soil C stocks for 0–20 cm. Soil water potential was the measured parameter most strongly associated with soil CO2 concentrations, with high CO2 values observed only once soil water potential at the 10 cm depth approached zero. This relationship was exhibited across a spectrum of timescales and was found to be significant at a daily timescale across all seasons using conditional nonparametric spectral Granger causality analysis. Hydrology plays a significant role in controlling CO2 efflux from the tree island soil, with soil CO2 dynamics differing by wetting mechanism. During the wet-up period, direct precipitation infiltrates soil from above and results in pulses of CO2 efflux from soil. The annual flood arrives later, and saturates soil from below. While CO2 concentrations in soil grew very high under both wetting mechanisms, the change in soil CO2 efflux was only significant when soils were wet from above.

Atributos de solos hidromórficos no Pantanal Norte Matogrossense

Resumo Os solos hidromorficos, comuns na Amazonia e no Pantanal, estao sujeitos a alternância natural de periodos de alagamento e secamento, que conduzem a uma formacao e caracteristicas diferenciadas. Estes solos guardam estreita relacao com a natureza do material de origem e com os processos de deposicao e sedimentacao. O objetivo neste trabalho foi avaliar as caracteristicas quimicas, morfologicas e mineralogicas de tres perfis de solos do Pantanal Norte Matogrossense (Planossolo, Plintossolo e Gleissolo), a fim de interpretar as relacoes entre suas propriedades e o ambiente em que foram formados. Os Planossolos e Gleissolos possuem maior fertilidade natural, evidenciada pelos valores expressivos de CTC (capacidade de troca de cations) e saturacao por bases. Os menores teores de Fe 2 O 3 do Planossolo estao relacionados com a reducao e remocao do Fe durante sua genese A mineralogia da fracao areia dos solos e constituida principalmente de quartzo, nodulos e concrecoes de Fe e de Mn, e em menor grau, biotita, muscovita e tracos de turmalina, magnetita, ilmenita, epidoto, zircao e rutilo. Os solos apresentaram perfil mineralogico semelhante na fracao argila, constituido por caulinita, esmectita, ilita e interestratificados do tipo ilitaesmectita. A mineralogia da fracao argila dos solos foi compativel com as diferencas quimicas constatadas entre eles, pois o Planossolo apresentou argila de maior atividade relativa as esmectitas e interestratificados ilita/esmectita, com maior soma de bases trocaveis e CTC, enquanto o Plintossolo e o Gleissolo, cujo mineral predominante foi a caulinita, apresentaram baixo teor de bases trocaveis e menor CTC. PalavRas-Chave: hidromorfismo, planicie de inundacao, ilita, argila de alta atividade. Attributes of the hydromorphic soils in the Pantanal of North Matogrosso

Soil and nutrient losses under different tillage systems in a clayey oxisol under natural rainfall

O processo erosivo e a principal causa de degradacao dos solos, trazendo, como consequencia, prejuizos ao setor agricola e ao meio ambiente, com reflexos economicos e tambem sociais. Este trabalho foi realizado com o objetivo de avaliar as perdas de solo e nutrientes em diferentes sistemas de preparo num Latossolo Vermelho-Amarelo acrico tipico. Foram instaladas cinco parcelas experimentais contendo os seguintes tratamentos: preparo convencional e cultivo morro abaixo (CMA); preparo convencional e plantio em nivel (CEN); preparo com uma grade aradora e uma niveladora e plantio em nivel (CNiv); preparo com duas gradagens niveladoras, plantio em nivel (NA) e cultivo minimo em nivel (CMN). As perdas de solo foram determinadas pelo metodo direto durante o ciclo da cultura de algodao, de dezembro de 2005 a junho de 2006. A cada coleta foram retiradas amostras de solo para quantificar as perdas dos nutrientes N, P, K e carbono orgânico (C-org) nos sedimentos. A diminuicao no revolvimento do solo proporcionou menores perdas de sedimento, nutrientes e C-org, destacando o CMN como o mais eficiente.O processo erosivo e a principal causa de degradacao dos solos, trazendo, como consequencia, prejuizos ao setor agricola e ao meio ambiente, com reflexos economicos e tambem sociais. Este trabalho foi realizado com o objetivo de avaliar as perdas de solo e nutrientes em diferentes sistemas de preparo num Latossolo Vermelho-Amarelo acrico tipico. Foram instaladas cinco parcelas experimentais contendo os seguintes tratamentos: preparo convencional e cultivo morro abaixo (CMA); preparo convencional e plantio em nivel (CEN); preparo com uma grade aradora e uma niveladora e plantio em nivel (CNiv); preparo com duas gradagens niveladoras, plantio em nivel (NA) e cultivo minimo em nivel (CMN). As perdas de solo foram determinadas pelo metodo direto durante o ciclo da cultura de algodao, de dezembro de 2005 a junho de 2006. A cada coleta foram retiradas amostras de solo para quantificar as perdas dos nutrientes N, P, K e carbono orgânico (C-org) nos sedimentos. A diminuicao no revolvimento do solo proporcionou menores perdas de sedimento, nutrientes e C-org, destacando o CMN como o mais eficiente. As perdas de N, P, K e C-org nos sedimentos apresentaram tendencias semelhantes as das perdas de solo, e N, P e K variaram conforme as adubacoes utilizadas. O C-org foi encontrado em maior quantidade no sedimento. A taxa de infiltracao basica (TIB) expressou diferenca entre os tratamentos na seguinte ordem em valores crescentes: CMA < CEN CNiv NA < CMN, demonstrando que os sistemas de preparo que minimizam a movimentacao do solo e incrementam C-org aumentam a TIB e diminuem o processo erosivo.

Biochar from sugarcane filtercake reduces soil CO2 emissions relative to raw residue and improves water retention and nutrient availability in a highly-weathered tropical soil.

In Brazil, the degradation of nutrient-poor Ferralsols limits productivity and drives agricultural expansion into pristine areas. However, returning agricultural residues to the soil in a stabilized form may offer opportunities for maintaining or improving soil quality, even under conditions that typically promote carbon loss. We examined the use of biochar made from filtercake (a byproduct of sugarcane processing) on the physicochemical properties of a cultivated tropical soil. Filtercake was pyrolyzed at 575°C for 3 h yielding a biochar with increased surface area and porosity compared to the raw filtercake. Filtercake biochar was primarily composed of aromatic carbon, with some residual cellulose and hemicellulose. In a three-week laboratory incubation, CO2 effluxes from a highly weathered Ferralsol soil amended with 5% biochar (dry weight, d.w.) were roughly four-fold higher than the soil-only control, but 23-fold lower than CO2 effluxes from soil amended with 5% (d.w.) raw filtercake. We also applied vinasse, a carbon-rich liquid waste from bioethanol production typically utilized as a fertilizer on sugarcane soils, to filtercake- and biochar-amended soils. Total CO2 efflux from the biochar-amended soil in response to vinasse application was only 5% of the efflux when vinasse was applied to soil amended with raw filtercake. Furthermore, mixtures of 5 or 10% biochar (d.w.) in this highly weathered tropical soil significantly increased water retention within the plant-available range and also improved nutrient availability. Accordingly, application of sugarcane filtercake as biochar, with or without vinasse application, may better satisfy soil management objectives than filtercake applied to soils in its raw form, and may help to build soil carbon stocks in sugarcane-cultivating regions.