Biochar combinado com resíduos orgânicos tem um reduzido efeito nas propriedades químicas do solo e no crescimento das plantas

Biochar has received great attention as a soil conditioner since it can potentially sequester carbon (C) in soil, enhance soil physical, chemical and biological properties and improve crop productivity. This study reports the results of a pot experiment with olive (Olea europaea L.), carried out in an acidic and clay loam textured soil, and cultivated during two growing seasons under eight fertilization treatments. They included mineral fertilization equivalent to a rate of 100 kg ha-1 of N, P2O5 and K2O (NPK), biochar applied at a rate of 10 (B10), and at 20 (B20) t biochar ha-1, biochar-NPK mixture (B10+NPK), biochar-waste mixtures with mushroom waste compost (B10+MWC), olive mill waste (B10 + OMW), and municipal solid waste (B10+MSW), the organic materials applied at a rate of 20 t ha-1, together with a treatment without fertilization (control). Biochar in the B20 treatment increased the soil C content in comparison to the control. Biochar in the B10+NPK treatment reduced soil nitrate levels compared to NPK treatment. No other benefits to soil properties, nutrient uptake or plant growth were observed with the use of biochar or any positive synergistic effect with the mixture of biochar with the other organic amendments. MSW, OMW and MWC tended to increase soil pH in comparison to the control. Most of the studies with biochar were carried out in soils with edaphic limitations or harsh environmental conditions limiting plant growth, which may have facilitated the detection of favorable effects. Under less limited soils or stressful conditions for plants, such as the ones established in this experiment, the benefits of using biochar were poor.El biochar ha recibido gran atención como acondicionador de suelo ya que puede potencialmente secuestrar carbono (C) en el suelo, mejorar sus propiedades físicas, químicas y biológicas y promover la productividad de los cultivos. Este trabajo muestra los resultados de una experiencia en macetas con olivo (Olea europaea L.), realizada en un suelo ácido y con textura franco arcillosa, cultivado durante dos estaciones de crecimiento. Se utilizaron ocho tratamientos, incluyendo fertilización mineral equivalente a 100 kg ha-1 de N, P2O5 y K2O (NPK), biochar aplicado a las dosis de 10 (B10) y 20 (B20) t ha-1, mezclas de biochar con fertilización mineral (B10+NPK) y con residuos de hongos (B10+MWC), residuos de aceite de oliva de almazaras (B10+OMW) y residuos sólidos urbanos (B10+RSU), aplicados a una tasa de 20 t ha-1, y un tratamiento sin fertilización (control). El biochar en el tratamiento B20 aumentó el contenido de C en el suelo en comparación con el control. El biochar en el tratamiento B10+NPK redujo los niveles de nitrato del suelo en comparación con el tratamiento NPK. No se registró ningún otro beneficio sobre las propiedades del suelo, la absorción de nutrientes o el crecimiento de las plantas por el uso de biochar o cualquier efecto sinérgico positivo con la mezcla de biochar con los otros correctivos orgánicos. MSW, OMW y MWC tendieron a aumentar el pH del suelo en comparación con el control. Muchos de los estudios anteriores con biochar se hicieron en suelos con limitaciones edáficas o condiciones ambientales adversas, lo que puede haber facilitado la aparición de efectos favorables. En condiciones menos estresantes para las plantas, como las establecidas en esta experiencia, los beneficios del uso del biochar parecen ser menos evidentes.O biochar tem recebido grande atenção como condicionador de solo, pois pode potencialmente sequestrar carbono (C) no solo, melhorar as propriedades físicas, químicas e biológicas do solo e promover a produtividade das culturas. Este trabalho relata os resultados de uma experiência em vasos com oliveira (Olea europaea L.), realizado em um solo ácido e de textura franco-argilosa, cultivada durante duas estações de crescimento. Oito tratamentos foram impostos, incluindo adubação mineral equivalente a 100 kg ha-1 de N, P2O5 e K2O (NPK), biochar aplicado nas doses de 10 (B10) e 20 (B20) t ha-1, misturas de biochar com adubação mineral (B10+NPK) e com composto de resíduos de cogumelos (B10+MWC), resíduos de lagar de azeite (B10+OMW) e resíduos sólidos urbanos (B10+RSU), aplicados a uma taxa de 20 t ha-1, e um tratamento sem fertilização (testemunha). O biochar no tratamento B20 aumentou o teor de C no solo em comparação à testemunha. O biochar no tratamento B10+NPK reduziu os níveis de nitrato do solo em comparação com o tratamento NPK. Nenhum outro benefício sobre as propriedades do solo, a absorção de nutrientes ou o crescimento das plantas foi registado pelo uso de biochar ou qualquer efeito sinérgico positivo com a mistura de biochar com os outros corretivos orgânicos. MSW, OMW e MWC tenderam a aumentar o pH do solo em comparação à testemunha. Muitos dos estudos anteriores com biochar foram feitos em solos com limitações edáficas ou condições ambientais adversas, o que pode ter facilitado o surgimento de efeitos favoráveis. Em condições menos stressantes para as plantas, como as estabelecidas nesta experiência, os benefícios do uso do biochar parecem ser menos evidentes.This work was funded by the INTERACT project – “Integrative Research in Environment, Agro-Chains and Technology”, no. NORTE-01- 0145-FEDER-000017, in its line of research entitled ISAC, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014/2020). The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013) and CITAB (UID/ AGR/04033/2019). The study was integrated under the activities of the Operational Group “Novas práticas em olivais de sequeiro: estratégias de mitigação e adaptação às alterações climáticas”, funded by PT2020 and EAFRD (European Agricultural Fund for Rural Development).info:eu-repo/semantics/publishedVersio

Water hyacinth (Eichhornia crassipes) detection using coarse and high resolution multispectral data

Efficient detection and monitoring procedures of invasive plant species are required. It is of crucial importance to deal with such plants in aquatic ecosystems, since they can affect biodiversity and, ultimately, ecosystem function and services. In this study, it is intended to detect water hyacinth (Eichhornia crassipes) using multispectral data with different spatial resolutions. For this purpose, high-resolution data (<0.1 m) acquired from an unmanned aerial vehicle (UAV) and coarse-resolution data (10 m) from Sentinel-2 MSI were used. Three areas with a high incidence of water hyacinth located in the Lower Mondego region (Portugal) were surveyed. Different classifiers were used to perform a pixel-based detection of this invasive species in both datasets. From the different classifiers used, the results were achieved by the random forest classifiers stand-out (overall accuracy (OA): 0.94). On the other hand, support vector machine performed worst (OA: 0.87), followed by Gaussian naive Bayes (OA: 0.88), k-nearest neighbours (OA: 0.90), and artificial neural networks (OA: 0.91). The higher spatial resolution from UAV-based data enabled us to detect small amounts of water hyacinth, which could not be detected in Sentinel-2 data. However, and despite the coarser resolution, satellite data analysis enabled us to identify water hyacinth coverage, compared well with a UAV-based survey. Combining both datasets and even considering the different resolutions, it was possible to observe the temporal and spatial evolution of water hyacinth. This approach proved to be an effective way to assess the effects of the mitigation/control measures taken in the study areas. Thus, this approach can be applied to detect invasive species in aquatic environments and to monitor their changes over time.This research activity was funded by POCI-FEDER as part of the project “BioComp_2.0— Produção de compostos orgânicos biológicos para o controlo do jacinto de água e para a valorização de subprodutos agropecuários, florestais e agroindustriais” (POCI-01-0247-FEDER-070123) and by national funds through FCT (Portuguese Foundation for Science and Technology) under the projects UIDB/04033/2020 and UIDB/00690/2020.info:eu-repo/semantics/publishedVersio

Power transformers winding fault diagnosis by the on-load exciting current extended Park's vector approach

This paper presents the application of the on-load exciting current Extended Park's Vector Approach to diagnose incipient turn-to-turn winding faults in operating power transformers. Experimental and simulation test results demonstrate the effectiveness of the proposed technique, which is based on the spectral analysis of the AC component of the on-load exciting current Park's Vector modulus

Glycation potentiates α-synuclein-associated neurodegeneration in synucleinopathies

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Input of sugarcane post-harvest residues into the soil

Sugarcane (Saccharum spp.) crops provide carbon (C) for soil through straw and root system decomposition. Recently, however, sugarcane producers are considering straw to be removed for electricity or second generation ethanol production. To elucidate the role of straw and root system on the carbon supply into the soil, the biomass inputs from sugarcane straw (tops and dry leaves) and from root system (rhizomes and roots) were quantified, and its contribution to provide C to the soil was estimated. Three trials were carried out in the State of Sao Paulo, Brazil, from 2006 to 2009. All sites were cultivated with the variety SP81 3250 under the green sugarcane harvest. Yearly, post-harvest sugarcane residues (tops, dry leaves, roots and rhizomes) were sampled; weighted and dried for the dry mass (DM) production to be estimated. On average, DM root system production was 4.6 Mg ha-1 year-1 (1.5 Mg C ha-1 year-1) and 11.5 Mg ha-1 year-1 (5.1 Mg C ha-1 year-1) of straw. In plant cane, 35 % of the total sugarcane DM was allocated into the root system, declining to 20 % in the third ratoon. The estimate of potential allocation of sugarcane residues to soil organic C was 1.1 t ha-1 year-1; out of which 33 % was from root system and 67 % from straw. The participation of root system should be higher if soil layer is evaluated, a deeper soil layer, if root exudates are accounted and if the period of higher production of roots is considered