829 research outputs found
Soil chemical, physical and biological properties subjected to cover crops in a terraced land cultivated with coffee and fruit trees
Get PDFA mensuração de atributos específicos do solo pode servir como potenciais indicadores da sua qualidade. O objetivo desse estudo foi avaliar os atributos químicos, físicos e biológicos de qualidade do solo em um sistema integrado de café (Coffea arabica L.), bananeira ‘Prata’ (Musa spp.), bananeira ‘Maçã’ (Musa acuminata × M. balbisiana) e abacateiro (Persea americana) em área terraceada, cultivado com plantas de cobertura. O terraceamento da área e o plantio foram realizados no primeiro semestre de 2020 na Unidade de Ensino, Pesquisa e Extensão (UEPE) do Departamento de Solos (DPS) da Universidade Federal de Viçosa (UFV) e a coleta das amostras de solos para a realização desse estudo foi realizada em maio de 2023. Utilizou-se o delineamento em blocos casualizados (DBC) com três repetições. Os tratamentos na entrelinha do cafeeiro foram compostos por braquiária (Urochloa ruziziensis), amendoim forrageiro (Arachis pintoi) e um tratamento controle com vegetação espontânea. As profundidades de solo avaliadas foram de 0–5, 5–10, 10– 20 e 20–40 cm. Os tratamentos com as plantas de cobertura foram capazes de aumentar os estoques de C orgânico total (COT), N total do solo (NT) e o C lábil (CL). O C da biomassa microbiana (CBM) e o quociente microbiano (qMic) foram superiores no tratamento de braquiária, enquanto a respiração basal do solo (RBS) e o quociente metabólico do solo (qCO2) foram maiores para o amendoim forrageiro. Quanto aos teores de nutrientes, a braquiária foi eficiente na ciclagem de K e Mg, enquanto o amendoim foi eficiente na ciclagem do P. Estes resultados sugerem que as plantas de cobertura foram capazes de sequestrar mais C no solo, aumentar a atividade microbiana e promover uma ciclagem eficiente de nutrientes, quando comparado à manutenção de somente plantas espontâneas. As respostas encontradas mostram que a agricultura tem um papel crucial na mitigação das consequências das mudanças climáticas, ao melhorar a qualidade do solo e com isso, aumentar o sequestro de C. Palavras-chave: Agricultura regenerativa; Saúde do solo; Sequestro de carbono.Soil chemical, physical and biological properties subjected to cover crops in a terraced land cultivated with coffee and fruit trees. Orientador: Clever Briedis. Coorientadores: Gustavo Franco de Castro e Rafael da Silva Teixeira. The measurement of specific soil attributes can serve as potential indicators of its quality. The aim of this study was to evaluate the chemical, physical, and biological attributes of soil quality in an integrated system of coffee (Coffea arabica L.), 'Prata' banana (Musa spp.), 'Maçã' banana (Musa acuminata × M. balbisiana), and avocado (Persea americana) in a terraced area, cultivated with cover crops. The terracing of the area and planting were carried out in the first semester of 2020 at the Teaching, Research, and Extension Unit (UEPE) of the Department of Soils (DPS) of the Federal University of Viçosa (UFV), and soil sample collection for this study was conducted in May 2023. A randomized complete block design (RCBD) with three replications was used. Treatments in the coffee interrows consisted of brachiaria (Urochloa ruziziensis), forage peanut (Arachis pintoi), and a control treatment with spontaneous vegetation. Soil depths evaluated were 0–5, 5–10, 10–20, and 20–40 cm. Cover crop treatments were able to increase total organic C (TOC) stocks, total soil N (TN), and labile C (LC). Microbial biomass C (MBC) and microbial quotient (qMic) were higher in the brachiaria treatment, while soil basal respiration (SBR) and soil metabolic quotient (qCO 2) were higher for forage peanut. Regarding nutrient contents, brachiaria was efficient in cycling K and Mg, while peanut was efficient in cycling P. These results suggest that cover crops were able to sequester more C in the soil, increase microbial activity, and promote efficient nutrient cycling compared to maintaining only spontaneous plants. The findings indicate that agriculture plays a crucial role in mitigating the consequences of climate change by improving soil quality and thereby increasing C sequestration. Keywords: Regenerative agriculture; Soil health; Carbon sequestration.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES
Compartimentos da matéria orgânica do solo, agregação, mecanismos de proteção e sequestro de carbono influenciados pela calagem superficial em sistema plantio direto
No full textA calagem é a prática mais utilizada para neutralizar a acidez do solo, porém promove também modificações químicas capazes de alterar os compartimentos da matéria orgânica do solo (MOS) e mecanismos de floculação, formação e estabilização de macro e microagregados. O objetivo desse trabalho foi avaliar o seqüestro de carbono, na amostra integral e nos agregados, e as alterações nos compartimentos da MOS afetados por calagem superficial em sistema plantio direto de longa duração. O experimento foi conduzido em um Latossolo Vermelho textura média, no município de Ponta Grossa, PR. O delineamento experimental foi o de blocos completos ao acaso em parcelas subdivididas, com três repetições. As parcelas consistiram da aplicação de calcário dolomítico na superfície do solo na dose de 0 ou 6 Mg ha-1 em 1993, e dose de 0 ou 3 Mg ha-1 em 2000 nas parcelas previamente com e sem calcário, compondo os tratamentos: 0+0; 6+0; 0+3 e 6+3 Mg ha-1. As subparcelas foram constituídas pelas profundidades de coleta, sendo realizadas em 0-2,5, 2,5-5, 5-10 e 10-20 cm de profundidade. As coletas de solo foram realizadas em setembro de 2008 e analisados os conteúdos de carbono orgânico total (COT) na amostra total, nos agregados e nas frações particulada (COP) e associada aos minerais (COAM) da matéria orgânica do solo (MOS). Agregados de 8-19 mm, da camada 0-2,5 cm, foram analisados através do uso de espectrômetro de dispersão de raios X (EDS) para a análise elementar de carbono (C) e cálcio (Ca). A calagem promoveu acúmulo de COT, principalmente na camada 0-2,5 cm. Os estoques de COT na camada de 0-20 cm foram 49,9, 52,9, 52,7 e 57,5 Mg ha-1 para os tratamentos 0+0, 6+0, 0+3 e 6+3, respectivamente. Os estoques nas frações da MOS também foram aumentados com a calagem. O aumento no estoque de COP foi estreitamente relacionado (R2=0,98; P=0,011) com a adição acumulada de C via resíduo cultural, a qual foi mais elevada nas parcelas que receberam calagem. Houve correlação positiva entre COT e carbono em água quente (CAQ), polissacarídeos totais (PT) e lábeis (PL). Correlações também demonstraram que o COT teve relação mais estreita com o COP do que com COAM, sugerindo maior influência da fração lábil no aumento de COT com a calagem. Nos agregados, a calagem proporcionou acúmulo de COT principalmente na profundidade de 0-2,5 cm. A calagem aumentou o diâmetro médio ponderado (DMP), proporcionando grande estoque de COT na classe de agregado 8-19 mm. A elevada proporção de agregados grandes nos tratamentos com calagem foi estreitamente correlacionado com o conteúdo de COT da amostra integral. A maior dose de calcário proporcionou aumento no estoque de COT tanto em COP quanto em COAM, visto principalmente na maior classe de agregados. A proporção de COP em relação ao COAM, na média dos tratamentos, nessa classe de agregados, diminuiu em profundidade, ficando em torno de 18, 13, 10 e 8 % nas profundidades de 0-2,5, 2,5-5, 5-10 e 10-20, respectivamente. Análise elementar de C e Ca demonstraram correlação positiva dos dois elementos contidos em uma secção da fração argila do centro de agregados de 8-19 mm. A aplicação de calcário, em solo dominado na fração argila por caulinita, traz benefícios à estruturação e promove aumento de C na amostra integral e nos agregados.Liming is the most often practice used to neutralize soil acidity, and also promotes chemical changes that can alter the soil organic matter (SOM) pools and the mechanisms of flocculation, formation and stabilization of macro-and microaggregates. The objective of this study was to evaluate carbon sequestration, in the whole and in the aggregates samples, and the changes in the SOM pools affected by liming in a long-term no-tillage. The experiment was conducted in an Oxisol, located in Ponta Grossa, PR. The experimental design was a randomized complete block, arranged as split plot with three replications. The main plot consisted of dolomite lime applied on the soil surface at a 0 or 6 Mg ha-1 in 1993, and 0 or 3 Mg ha-1 in 2000 in plots previously with and without lime, and the treatments was assigned as: 0+0, 6+0, 0+3 and 6+3 Mg ha-1. The subplots were represented by sampling depth and consist of 0-2.5, 2.5-5, 5-10 and 10-20 cm layer. The soil samples were taken in September 2008 and the total organic carbon (TOC) was analyzed in the whole sample, in the aggregates and in the particulate organic carbon (POC) and in the fraction associated with minerals carbon (OCAM). Aggregates of 8-19 mm, in the 0-2.5 cm layer were analyzed by using scan microscope spectrometer X-ray (EDS) for elemental analysis of carbon (C) and calcium (Ca). Liming promoted accumulation of TOC mainly in the layer 0-2.5 cm. The TOC stocks at 0-20 cm were 49.9, 52.9, 52.7 and 57.5 Mg ha-1 for 0+0, 6+0, 0+3, 6 +3 treatments, respectively. Stocks in the SOM fractions were also increased with liming. The increase in POC stock was close relationship (R2 = 0.98, P = 0.011) with the C accumulated input through crop residue, which was higher in plots that were limed. A positive correlation was found between TOC and C extracted in hot water (CHW), total polysaccharides (TP) and labile (LP). Correlations also showed that TOC had a closer relationship with POC than with OCAM, suggesting a greater influence on the labile fraction of TOC increase with liming. In aggregate, the effect of liming in TOC accumulation was mainly in 0-2.5 cm depth. The treatments with liming showed high mean weight diameter (MWD), which provided a large stock of TOC in the 8-19 mm aggregate size. A higest proportion of large aggregates with liming was closely correlated with the TOC content of whole sample. The highest liming dosis resulted in both COP and in OCAM, in the largest class of aggregates. The proportion of POC average of the treatments in relation to OCAM, this class of aggregates, has decreased in depth, and were 18, 13, 10 and 8% at depths of 0-2.5, 2.5-5, 50-10 and 10-20, respectively. Elemental analysis of C and Ca showed a positive correlation of those elements contained in a section of clay from the center of 8-19 mm aggregates. The results suggest that application of lime in soil with clay fraction dominated by kaolinite, brings benefits to structuring and promotes an increase of C in the whole sample and in aggregates
Carbon indices to assess quality of management systems in a Subtropical Acrisol.
Get PDFManagement systems to improve soil quality are essential for agricultural and environmental sustainability. We assessed the quality of soil management systems applied to a subtropical Acrisol in terms of the carbon management index (CMI), the stratification ratio for total organic carbon (SR-TOC) and light fraction of organic matter (SR-LF). In addition, we examined their relationship to chemical, physical and biological soil quality indicators, as well as to maize yield. The study was conducted on a long-term experiment (18 years) in southern Brazil involving two different systems [no tillage (NT) and conventional tillage (CT)], two cropping systems [black oat/maize (O/M) and black oat + vetch/maize + cowpea (OV/MC)] and two nitrogen fertilizer rates for maize (0 and 180 kg ha?1). Based on the three indices, the best managements for soil quality comprised NT (50-212 % better than CT), legume cover crops (10-47 % better than O/M) and N fertilization (8-33 % better than no fertilizer). All three indices proved accurate to assess the impact of soil management systems, especially SR-LF, which showed increased sensitivity and close relationships with chemical, physical and biological soil quality indicators. On the other hand, a poor relationship was observed between soil C indices and maize yield, which was improved only by legume cover crops and N fertilization. The results showed that the association of no-till system to an abundant supply of crop residues is key to ensure high soil quality and crop yields in humid subtropical regions
Clever girls' stories: the girl they call a nerd
Get PDFIn this paper we explore the issue of gender and mathematics participation, focusing on the ways in which “clever girls” self-author within the discourse order of a high ability group, which has particular significance in the Norwegian context in which this study took place. Contrasting the cases of three girls, only one of whom (Anna) chooses to continue with a higher level of mathematics (mathematics for science), we consider the ways in which they manage being members of the “smart group”. We analyse in particular the storying of Anna as a “nerd”, and the social cost of being a “clever girl” against the backdrop of a public discourse of equality of opportunity in Norway
A brilliant creator or a clever entrepreneur? : study of issues of great creativity workshops of Red Ruthenia in the eighteenth century
No full textThe following article centers around the issue of an artist and his method of art creating.
The author describes in great detail the situation of an artist in eighteen century, proving
that back then the heart of art creation were great creativity workshops, managed by
artists themselves. With such introduction provided, the author stated a question whether
eighteen century artists were brilliant creators or rather clever entrepreneurs
Knowledge sharing strategies for Project Knowledge Management in the automotive sector
No full textProject Knowledge Management is regarded as a field of increasing importance for both researchers and organisations. This led Volvo Technology, the innovation business unit within a Swedish automotive multinational corporation, to explore through a qualitative case study how Project Knowledge Management could be improved to support knowledge sharing between projects within the organisation. The current situation of Project Knowledge Management is described through a developed theoretical framework and with input from thirteen semi-structured interviews conducted and analysed in an iterative fashion. The description shows that the contributor employs the codification strategy to share knowledge with other projects while the receiver adapts a personalisation strategy to retrieve knowledge from other projects. This description was analysed and compared with current research through brainstorming. Since there are current initiatives within the organisation to improve the codification strategy, this research focuses on improving the personalisation strategy. The recommendation was to promote Communities of Practice. Six semi-structured interviews were conducted to evaluate the relevance of the recommendations. The recommendation was found to be relevant for improving Project Knowledge Management within Volvo Technology
A Tiny Tot Presentation
No full textThis booklet of sixteen pages contains three stories: The Snake and the Crows, The Monkeys and the Demon, and The Monkey and the Log. In this version of the first story, the clever fox advises the crows to pick up a princess' gold necklace and drop it into the snake's hole. The demon in the second story forbids the monkeys to drink from his lake, but apparently he himself cannot leave the lake. So the clever monkey-king devises a long tube from bamboo reeds and drinks out of the lake at a distance. In the third story, the curious monkey who pulls the wedge out of the tree is crushed to death. In most versions, just one part of his anatomy is--painfully--caught in the veritable vice that closes when the wedge is removed. The illustrations are large, simple cartoons. The monkeys' faces seem quite human. I am including for author and illustrator names that appeared when I did a websearch for the book.Sadhna Kapur
A READING OF "CLEVER LITTLE NURSES" BY TEREZA QUADROS, MASK OF CLARICE LISPECTOR
No full textEste artigo apresenta uma leitura da crônica “Enfermeirinhas espertas”, de Tereza Quadros (máscara de Clarice Lispector), publicada no semanário Comício, em 1952. A escritora era responsável pela coluna feminina “Entre mulheres” do veículo. Nessa página, a colunista publicou crônicas com incontestável valor literário, sendo que algumas delas deram origem a contos publicados posteriormente na obra lispectoriana.This article presents a reading of the literary chronicle "Clever Little Nurses" by Tereza Quadros (mask of Clarice Lispector), published in the weekly journal Comício in 1952. The writer was responsible for the journal's the feminine column "Among Women". On those pages, the columnist published literary chronicles of indisputable value, with a few of them originating short stories later published by the author
Measuring Spurious Correlation in Classification: 'Clever Hans' in Translationese
Get PDFRecent work has shown evidence of 'Clever Hans' behavior in high-performance
neural translationese classifiers, where BERT-based classifiers capitalize on
spurious correlations, in particular topic information, between data and target
classification labels, rather than genuine translationese signals.
Translationese signals are subtle (especially for professional translation) and
compete with many other signals in the data such as genre, style, author, and,
in particular, topic. This raises the general question of how much of the
performance of a classifier is really due to spurious correlations in the data
versus the signals actually targeted for by the classifier, especially for
subtle target signals and in challenging (low resource) data settings. We focus
on topic-based spurious correlation and approach the question from two
directions: (i) where we have no knowledge about spurious topic information and
its distribution in the data, (ii) where we have some indication about the
nature of spurious topic correlations. For (i) we develop a measure from first
principles capturing alignment of unsupervised topics with target
classification labels as an indication of spurious topic information in the
data. We show that our measure is the same as purity in clustering and propose
a 'topic floor' (as in a 'noise floor') for classification. For (ii) we
investigate masking of known spurious topic carriers in classification. Both
(i) and (ii) contribute to quantifying and (ii) to mitigating spurious
correlations.Comment: Accepted to RANLP 2023 (oral
Management of Meaning in Organizations : 3 x in Inventing, Innovating, Interpreting, Poznań, June 27, 2008
No full textThe goal of this paper is to present advantages and disadvantages of clever people management and to begin discussion about their positive and negative impact on organization. In the present world managers and researchers underline the value of innovation and creativity in business, so as a natural result of such way of thinking, clever people became the most wanted type of employee. In this paper the author analyzed main environmental factors of “clever people age” beginning, explained the definition of “clever people”, described roles of clever people in organizations, analyzed problems of management caused by this group of employees, analyzed the new meaning of knowledge management based on clever people175-17
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