bluuebunny/crossref_metadata_2025 huggingface dataset:
Principles of targeting endothelial cell metabolism to treat angiogenesis and endothelial cell dysfunction in disease
Authors: Goveia Jermaine , Stapor Peter , Carmeliet Peter
Published: July 2014

The endothelium is the orchestral conductor of blood vessel function. Pathological blood vessel formation (a process termed pathological angiogenesis) or the inability of endothelial cells (ECs) to perform their physiological function (a condition known as EC dysfunction) are defining features of various diseases. Therapeutic intervention to inhibit aberrant angiogenesis or ameliorate EC dysfunction could be beneficial in diseases such as cancer and cardiovascular disease, respectively, but current strategies have limited efficacy. Based on recent findings that pathological angiogenesis and EC dysfunction are accompanied by EC‐specific metabolic alterations, targeting EC metabolism is emerging as a novel therapeutic strategy. Here, we review recent progress in our understanding of how EC metabolism is altered in disease and discuss potential metabolic targets and strategies to reverse EC dysfunction and inhibit pathological angiogenesis.
Noncoding RNAs and the control of hormonal signaling via nuclear receptor regulation
Authors: Ottaviani Silvia , de Giorgio Alexander , Harding Victoria , Stebbing Justin , Castellano Leandro
Published: July 2014

Despite its identification over 100 years ago, new discoveries continue to add to the complexity of the regulation of the endocrine system. Today the nuclear receptors (NRs) that play such a pivotal role in the extensive communication networks of hormones and gene expression remain an area of intense research. By orchestrating core processes, from metabolism to organismal development, the gene expression programs they control are dependent on their cellular context, their own levels, and those of numerous co-regulatory proteins. A previously unknown component of these networks, noncoding RNAs (ncRNAs) are now recognized as potent regulators of NR signaling, influencing receptor and co-factor levels and functions while being reciprocally regulated by the NRs themselves. This review explores the regulation enacted by microRNAs and long ncRNAs on NR function, using representative examples to show the varied roles of ncRNAs, in turn producing significant effects on the NR functional network in health and disease.
Altered VEGF-stimulated Ca2+ signaling in part underlies pregnancy-adapted eNOS activity in UAEC
Authors: Boeldt Derek S , Grummer Mary A , Magness Ronald R , Bird Ian M
Published: July 2014

In pregnancy, the uterine vasculature undergoes dramatic vasodilatory adaptations. Previously, vascular endothelial growth factor (VEGF) has been shown to stimulate endothelial nitric oxide synthase (eNOS) in uterine artery endothelial cells (UAECs) derived from pregnant ewes to a greater extent than those from non-pregnant ewes in a manner not fully explained by changes in the phosphorylation of eNOS. In this study, we used Fura-2 Ca2+imaging and arginine-to-citrulline conversion eNOS activity assays to assess the importance of VEGF-stimulated Ca2+responses in pregnancy-related changes in NO production in UAEC. In this study, we show that pregnancy-induced changes in VEGF-stimulated Ca2+responses could account in part for the greater capacity of VEGF to stimulate eNOS in UAECs from pregnant versus non-pregnant animals. VEGF-stimulated Ca2+responses in UAECs from pregnant and non-pregnant animals were mediated through VEGF receptor 2 and were detected in roughly 15% of all cells. There were no pregnancy-specific differences in area under the curve or peak height. UAECs from pregnant animals were more consistent in the time to response initiation, had a larger component of extracellular Ca2+entry, and were more sensitive to a submaximal dose of VEGF. In UAECs from pregnant and non-pregnant animals Ca2+responses and eNOS activation were sensitive to the phospholipase C/inositol 1,4,5-trisphosphate pathway inhibitors 2-aminoethoxydiphenylborane and U73122. Thus, changes in VEGF-stimulated [Ca2+]iare necessary for eNOS activation in UAECs, and pregnancy-induced changes in Ca2+responses could also in part explain the pregnancy-specific adaptive increase in eNOS activity in UAECs.
20 YEARS OF LEPTIN: Insights into signaling assemblies of the leptin receptor
Authors: Peelman Frank , Zabeau Lennart , Moharana Kedar , Savvides Savvas N , Tavernier Jan
Published: July 2014

Leptin plays a central role in the control of body weight and energy homeostasis, but is a pleiotropic cytokine with activities on many peripheral cell types. In this review, we discuss the interaction of leptin with its receptor, and focus on the structural and mechanistic aspects of the extracellular aspects of leptin receptor (LR) activation. We provide an extensive overview of all structural information that has been obtained for leptin and its receptor via X-ray crystallography, electron microscopy, small-angle X-ray scattering, homology modeling, and mutagenesis studies. The available knowledge is integrated into putative models toward a recapitulation of the LR activation mechanism.
20 YEARS OF LEPTIN: Role of leptin in energy homeostasis in humans
Authors: Rosenbaum Michael , Leibel Rudolph L
Published: July 2014

The hyperphagia, low sympathetic nervous system tone, and decreased circulating concentrations of bioactive thyroid hormones that are common to states of congenital leptin deficiency and hypoleptinemia following and during weight loss suggest that the major physiological function of leptin is to signal states of negative energy balance and decreased energy stores. In weight-reduced humans, these phenotypes together with pronounced hypometabolism and increased parasympathetic nervous system tone create the optimal circumstance for weight regain. Based on the weight loss induced by leptin administration in states of leptin deficiency (obese) and observed similarity of phenotypes in states of congenital and dietary-induced states of hypoleptinemia (reduced obese), it has been suggested that exogenous leptin could potentially be useful in initiating, promoting, and sustaining weight reduction. However, the responses of human beings to exogenous leptin administration are dependent not only on extant energy stores but also on energy balance. Leptin administration to humans at usual weight has little, if any, effect on body weight while leptin administration during weight loss mitigates hunger, especially if given in supraphysiological doses during severe caloric restriction. Leptin repletion is most effective following weight loss by dietary restriction. In this state of weight stability but reduced energy stores, leptin at least partially reverses many of the metabolic, autonomic, neuroendocrine, and behavioral adaptations that favor weight regain. The major physiological function of leptin is to signal states of negative energy balance and decreased energy stores. Leptin, and pharmacotherapies affecting leptin signaling pathways, is likely to be most useful in sustaining weight loss.
Progesterone improves the maturation of male-induced preovulatory follicles in anoestrous ewes
Authors: Adib Achraf , Freret Sandrine , Touze Jean-Luc , Lomet Didier , Lardic Lionel , Chesneau Didier , Estienne Anthony , Papillier Pascal , Monniaux Danielle , Pellicer-Rubio Maria-Teresa
Published: July 2014

The first ovulation induced by male effect in sheep during seasonal anoestrus usually results in the development of a short cycle that can be avoided by progesterone priming before ram introduction. In elucidating the involvement of the hypothalamic–pituitary–gonadal axis in the occurrence of short cycles, the effects of progesterone and the time of anoestrus on the development of male-induced preovulatory follicles were investigated in anoestrous ewes using morphological, endocrine and molecular approaches. Ewes were primed with progesterone for 2 (CIDR2) or 12 days (CIDR12) and untreated ewes used as controls during early (April) and late (June) anoestrus. The duration of follicular growth and the lifespan of the male-induced preovulatory follicles were prolonged by ∼1.6 days in CIDR12 ewes compared with the controls. These changes were accompanied by a delay in the preovulatory LH and FSH surges and ovulation. Intra-follicular oestradiol concentration and mRNA levels ofLHCGRandSTARin the granulosa and theca cells of the preovulatory follicles were higher in CIDR12 ewes than the control ewes. The expression of mRNA levels ofCYP11A1andCYP17A1also increased in theca cells of CIDR12 ewes. CIDR2 ewes gave intermediate results. Moreover, ewes ovulated earlier in June than in April, without changes in the duration of follicular growth, but these effects were unrelated to the lifespan of corpus luteum. Our results give the first evidence supporting the positive effect of progesterone priming on the completion of growth and maturation of preovulatory follicles induced by male effect in seasonal anoestrous ewes, thereby preventing short cycles.
Importance of the interdisciplinary, evidence-based diagnosis of polycystic ovary syndrome
Authors: Gődény Sándor , Csenteri Orsolya
Published: July 2014

Polycystic ovary syndrome is recognized as the most common hormonal and metabolic disorder of women. This heterogeneous endocrinopathy characterized by clinical and/or biochemical hyperandrogenism, oligo- or amenorrhoea, anovulatory infertility, and polycystic ovarian morphology. The prevalence, clinical feature and the risk of co-morbidity vary depending on the accuracy of the diagnosis and the criteria used. Evidence suggests that those women are at high risk who fulfil the criteria based on National Institute of Health. The complex feature of the syndrome and the considerable practice heterogenity that is present with regards to diagnostic testing of patients who are suspected to have polycystic ovary syndrome require an interdisciplinary, evidence-based diagnostic approach. Such a method can ensure the patient safety and the effectiveness and efficiency of the diagnosis. This paper summarises the highest available evidence provided by well-designed studies, meta-analysis and systematic reviews of the clinical feature and the clinical implications of the diagnostic criteria of polycystic ovary syndrome. Orv. Hetil., 2014, 155(30), 1175–1188.
Outcome of a one-year behavior therapy weight loss program
Authors: Papp Ildikó , Czeglédi Edit , Udvardy-Mészáros Ágnes , Vizin Gabriella , Perczel Forintos Dóra
Published: July 2014

Introduction: Treatment of obesity has become one of the most challenging issues. Aim: The aims of the authors were to present the results of standard behavior therapy weight loss program combined with self-help and the results of one-year follow-up. Method: The 24-week program involved 41 participants of which 33 subjects participated in the follow-up. Anthropometric data were obtained and the participants were asked to fill questionnaires (the 21 items Three Factor Eating Questionnair Revised 21 items; Physical Exercise: Steps of change [Short Form]. Results: 87.8% of participants achieved a minimum weight loss of 5% which is the rate expected in professional therapies for obesity. Significant changes in maladaptive eating pattern and an increase in the rate of regular exercise were observed. Significant association was found between the increase of cognitive restraint and the rate of weight loss during treatment. At one-year follow-up the majority of participants (75.8%) did keep their minimum weight loss of 5% and they showed significant change in eating pattern. Conclusions: The results suggest that standard behavior therapy extended with self-help elements may be a cost-effective treatment of obesity. Orv. Hetil., 2014, 155(30), 1196–1202.
Pedotransfer functions to predict water retention for soils of the humid tropics: a review
Authors: Botula Yves-Dady , Van Ranst Eric , Cornelis Wim M.
Published: July 2014

Over the past three decades, pedotransfer functions (PTFs) have been widely used by soil scientists to estimate soils properties in temperate regions in response to the lack of soil data for these regions. Several authors indicated that little effort has been dedicated to the prediction of soil properties in the humid tropics, where the need for soil property information is of even greater priority. The aim of this paper is to provide an up-to-date repository of past and recently published articles as well as papers from proceedings of events dealing with water-retention PTFs for soils of the humid tropics. Of the 35 publications found in the literature on PTFs for prediction of water retention of soils of the humid tropics, 91 % of the PTFs are based on an empirical approach, and only 9 % are based on a semi-physical approach. Of the empirical PTFs, 97 % are continuous, and 3 % (one) is a class PTF; of the empirical PTFs, 97 % are based on multiple linear and polynomial regression of n th order techniques, and 3 % (one) is based on the k-Nearest Neighbor approach; 84 % of the continuous PTFs are point-based, and 16 % are parameter-based; 97 % of the continuous PTFs are equation-based PTFs, and 3 % (one) is based on pattern recognition. Additionally, it was found that 26 % of the tropical water-retention PTFs were developed for soils in Brazil, 26 % for soils in India, 11 % for soils in other countries in America, and 11 % for soils in other countries in Africa.
Evaluation of statistical and geostatistical models of digital soil properties mapping in tropical mountain regions
Authors: Carvalho Junior Waldir de , Chagas Cesar da Silva , Lagacherie Philippe , Calderano Filho Braz , Bhering Silvio Barge
Published: July 2014

Soil properties have an enormous impact on economic and environmental aspects of agricultural production. Quantitative relationships between soil properties and the factors that influence their variability are the basis of digital soil mapping. The predictive models of soil properties evaluated in this work are statistical (multiple linear regression-MLR) and geostatistical (ordinary kriging and co-kriging). The study was conducted in the municipality of Bom Jardim, RJ, using a soil database with 208 sampling points. Predictive models were evaluated for sand, silt and clay fractions, pH in water and organic carbon at six depths according to the specifications of the consortium of digital soil mapping at the global level (GlobalSoilMap). Continuous covariates and categorical predictors were used and their contributions to the model assessed. Only the environmental covariates elevation, aspect, stream power index (SPI), soil wetness index (SWI), normalized difference vegetation index (NDVI), and b3/b2 band ratio were significantly correlated with soil properties. The predictive models had a mean coefficient of determination of 0.21. Best results were obtained with the geostatistical predictive models, where the highest coefficient of determination 0.43 was associated with sand properties between 60 to 100 cm deep. The use of a sparse data set of soil properties for digital mapping can explain only part of the spatial variation of these properties. The results may be related to the sampling density and the quantity and quality of the environmental covariates and predictive models used.
Assessment of pedotransfer functions for estimating soil water retention curves for the amazon region
Authors: Medeiros João Carlos , Cooper Miguel , Dalla Rosa Jaqueline , Grimaldi Michel , Coquet Yves
Published: July 2014

Knowledge of the soil water retention curve (SWRC) is essential for understanding and modeling hydraulic processes in the soil. However, direct determination of the SWRC is time consuming and costly. In addition, it requires a large number of samples, due to the high spatial and temporal variability of soil hydraulic properties. An alternative is the use of models, called pedotransfer functions (PTFs), which estimate the SWRC from easy-to-measure properties. The aim of this paper was to test the accuracy of 16 point or parametric PTFs reported in the literature on different soils from the south and southeast of the State of Pará, Brazil. The PTFs tested were proposed by Pidgeon (1972), Lal (1979), Aina & Periaswamy (1985), Arruda et al. (1987), Dijkerman (1988), Vereecken et al. (1989), Batjes (1996), van den Berg et al. (1997), Tomasella et al. (2000), Hodnett & Tomasella (2002), Oliveira et al. (2002), and Barros (2010). We used a database that includes soil texture (sand, silt, and clay), bulk density, soil organic carbon, soil pH, cation exchange capacity, and the SWRC. Most of the PTFs tested did not show good performance in estimating the SWRC. The parametric PTFs, however, performed better than the point PTFs in assessing the SWRC in the tested region. Among the parametric PTFs, those proposed by Tomasella et al. (2000) achieved the best accuracy in estimating the empirical parameters of the van Genuchten (1980) model, especially when tested in the top soil layer.
Compared performance of penetrometers and effect of soil water content on penetration resistance measurements
Authors: Mome Filho Edison Aparecido , Silva Alvaro Pires da , Figueiredo Getulio Coutinho , Gimenes Fernando Henrique Setti , Vitti André Cesar
Published: July 2014

Modern agriculture techniques have a great impact on crops and soil quality, especially by the increased machinery traffic and weight. Several devices have been developed for determining soil properties in the field, aimed at managing compacted areas. Penetrometry is a widely used technique; however, there are several types of penetrometers, which have different action modes that can affect the soil resistance measurement. The objective of this study was to compare the functionality of two penetrometry methods (manual and automated mode) in the field identification of compacted, highly mechanized sugarcane areas, considering the influence of soil water volumetric content (θ) on soil penetration resistance (PR). Three sugarcane fields on a Rhodic Eutrudrox were chosen, under a sequence of harvest systems: one manual harvest (1ManH), one mechanized harvest (1MH) and three mechanized harvests (3MH). The different degrees of mechanization were associated to cumulative compaction processes. An electronic penetrometer was used on PR measurements, so that the rod was introduced into the soil by hand (Manual) and by an electromechanical motor (Auto). The θ was measured in the field with a soil moisture sensor. Results showed an effect of θ on PR measurements and that regression models must be used to correct data before comparing harvesting systems. The rod introduction modes resulted in different mean PR values, where the "Manual" overestimated PR compared to the "Auto" mode at low θ.
Penetrômetro de impacto stolf - programa computacional de dados em EXCEL-VBA
Authors: Stolf Rubismar , Murakami Jorge Hiroshi , Brugnaro Caetano , Silva Luiz Gabriel , Silva Luiz Carlos Ferreira da , Margarido Luiz Antonio Correia
Published: July 2014

Há dois principais tipos de penetrômetro, o estático e o dinâmico. No primeiro, uma haste com uma ponta cônica é introduzida contínua e lentamente (quase estático), registrando-se concomitantemente a força de reação que é igual à resistência do solo. No segundo, utiliza-se a mesma haste. Contudo, esta é introduzida por meio da promoção de uma massa de impacto em queda livre. Dessa forma, a teoria pode ser tratada pela dinâmica newtoniana para obtenção da resistência. O objetivo do programa é proporcionar uma ferramenta rápida, facilitadora da computação de dados de resistência do solo, para esse último penetrômetro, resultando tabelas e gráficos já no formato científico. Desenvolvido em linguagem de programação Visual Basic Aplication (VBA), escolheu-se o aplicativo Excel como interface com o usuário pela sua popularidade. É constituído por quatro planilhas, duasauxiliares, sendo duas delas essenciais, Plan1 e 2: Plan1 - dados de entrada (número de impactos e profundidade). Concomitante à digitação, a tabela de resistência é confeccionada com o respectivo gráfico, podendo tabelar 40 perfis. Plan2 - cumpre função especial de equalizar, ou seja, padronizar a profundidade em camadas constantes, permitindo unificar todos os perfis em uma única tabela. Para tal, escolhe-se uma espessura de camada (exemplo: 5 cm); em seguida, o programa coleta os dados de resistência (MPa) da Plan1 e interpola os valores para a profundidade de 5 em 5 cm. Após realizar esse procedimento para todas as tabelas da Plan1, o programa gera, na Plan2, uma única tabela com todos os perfis, a média geral e os respectivos gráficos. É possível selecionar os perfis; por exemplo, apenas os medidos na linha ou entrelinha de plantio e eliminar perfis a critério do usuário. Como objetivo complementar, descreve-se a evolução do projeto "Penetrômetro de impacto", iniciado em 1982, cuja técnica passou a ser adotada no meio científico, após a publicação da teoria nesta revista em 1991. Apresenta-se também levantamento no meio científico nos últimos três anos (2010-2012), propiciando uma visão das principais aplicações na atualidade.
Frações oxidáveis do carbono orgânico total e macrofauna edáfica em sistema de integração lavoura-pecuária
Authors: Batista Itaynara , Correia Maria Elizabeth Fernandes , Pereira Marcos Gervasio , Bieluczyk Wanderlei , Schiavo Jolimar Antonio , Rouws Janaína Ribeiro Costa
Published: July 2014

O crescente nível de degradação das terras tem promovido a adoção de manejos agrícolas que busque aliar a produção agropecuária à conservação do solo. Entre esses, a prática da Integração Lavoura-Pecuária (ILP) tem intensificado-se no Centro-Oeste brasileiro. Com o objetivo de avaliar o efeito em longo prazo do sistema ILP e da sazonalidade, sob a comunidade da macrofauna edáfica e das frações oxidáveis do carbono orgânico total (COT) em áreas de cultivo e Cerradão, foi desenvolvido na Fazenda Cabeceira no município de Maracaju, MS, um estudo em que se mensurou a influência da ILP sobre as frações oxidáveis do COT e sobre a macrofauna edáfica. O sistema ILP está sendo utilizado nessa área desde 2003; o solo foi identificado como Latossolo Vermelho, localizado em área de relevo plano. As áreas amostradas possuem o seguinte histórico: soja/milho + braquiária/algodão/ aveia + pastagem/soja/formação da pastagem/pastagem; as amostragens foram realizadas na época seca, em que as culturas presentes eram pasto, milho+braquiária e algodão; e na chuvosa, com milho+braquiária, algodão e soja. Assim, as áreas nas duas épocas de avaliação foram: pasto/milho, milho+braquiária/ algodão, algodão/soja e uma área nativa de Cerradão. A amostragem foi realizada nas profundidades de 0-10, 10-20 e 20-30 cm, sendo feitas as seguintes determinações: análise da macrofauna edáfica, fracionamento granulométrico da matéria orgânica do solo (MOS) e frações oxidáveis do COT. As áreas não apresentavam delineamento experimental, sendo este um estudo de observação. Os dados foram comparados pelo teste de Kruskal Wallis a 5 % e por meio da análise de redundância. A compartimentalização da MOS pode ser utilizada para a avaliação da qualidade do manejo, sendo os compartimentos mais sensíveis as frações F1 e F2 de frações oxidáveis, pois são mais lábeis no solo, já as frações F3 e F4 são as mais recalcitrantes. Isoptera (cupim) pode estar atuando como agente humificador da matéria orgânica na área de Cerradão, contribuindo para maiores teores de F3 e F4, em relação à F1 e F2 na época seca. Esse padrão somente foi verificado na área de Cerradão, visto que nas áreas de produção, Isoptera é controlado pelo manejo. A falta desse inseto no sistema ILP pode estar reduzindo a estabilização da MOS nas frações F3 e F4.
Soluble carbon in oxisol under the effect of organic residue rates
Authors: Pinheiro Gabriela Lúcia , Silva Carlos Alberto , Lima José Maria de
Published: July 2014

The application of organic residues to the soil can increase soluble organic carbon (SOC) and affect the pH and electrolytic conductivity (EC) of the soil. However, the magnitude of these changes depends on the type of residue and the applied dose. This study aimed to evaluate the effect of increasing C rates contained in organic residue on the pH, EC, water-extractable total carbon (WETC), water-extractable organic carbon (WEOC), and water-extractable inorganic carbon (WEIC) in soil treated with manure (chicken, swine, and quail), sawdust, coffee husk, and sewage sludge. The levels of total C (TC- KH2PO4), organic carbon (OC- KH2PO4), and inorganic C (IC- KH2PO4) extractable by a 0.1 mol L-1 KH2PO4 solution were also quantified in soil under the effect of increasing rates of chicken and quail manures. The following rates of organic residue C were applied to a dystrophic Red Latosol (Oxisol) sample: 0, 2,000, 5,000, 10,000, and 20,000 mg kg-1. The addition of organic residues to the soil increased pH, except in the case of sewage sludge, which acidified the soil. The acidity correction potential of chicken and quail manure was highest, dependent on the manure rate applied; regardless of the dose used, sawdust barely alters the soil pH. At all tested rates, the EC of the soil treated with swine manure, coffee husk, and sawdust remained below 2.0 dS m-1, which is a critical level for salinity-sensitive crops. However, the application of chicken or quail manure and sewage sludge at certain rates increased the EC to values above this threshold level. Highest levels of WETC, WEOC, and WEIC were obtained when chicken and quail manure and coffee husk were applied to the Oxisol. The quantities of SOC extracted by KH2PO4 were higher than the quantities extracted by water, demonstrating the ability of soil to adsorb C into its colloids.
Tolerância de mamona a zinco avaliada por fluorescência de clorofila e nutrição das plantas
Authors: Marques Marise Conceição , Nascimento Clístenes Williams Araújo do
Published: July 2014

A medida da fluorescência de clorofila pode ser uma ferramenta útil para detectar alterações no aparato fotossintético das plantas. Considerando que a detecção precoce da contaminação de zinco em plantas é essencial para o monitoramento ambiental, este trabalho objetivou avaliar o estresse causado por esse nutriente em plantas de mamona (Ricinus communis), utilizando a técnica da fluorescência de clorofila. As alterações provocadas pelo Zn nos pigmentos fotossintéticos e na composição mineral das plantas foram também estudadas. Plantas de mamona foram cultivadas durante 28 dias em solução nutritiva com cinco doses de Zn (100, 200, 300, 400 e 600 µmol L-1), além de um controle contendo 0,380 µmol L-1 do elemento. A fluorescência de clorofila detectou alterações temporais promovidas pelo acúmulo de Zn nas plantas e evidenciou-se útil na detecção precoce da toxicidade do elemento em plantas de mamona. Apesar do declínio no seu estado nutricional, a mamona apresentou relativa tolerância à toxicidade a doses elevadas de Zn, indicando ser essa espécie uma alternativa atraente para revegetação ou remediação de áreas contaminadas.
Avaliação nutricional de feijoeiro irrigado pelos métodos CND, DRIS e faixas de suficiência
Authors: Partelli Fábio Luiz , Dias Jairo Rafael Machado , Vieira Henrique Duarte , Wadt Paulo Guilherme Salvador , Paiva Júnior Edmar
Published: July 2014

A cultura do feijoeiro tem grande importância para o Estado de Goiás, Brasil. No entanto, informações relacionadas aos padrões nutricionais para condições irrigadas são carentes na região. Os objetivos deste trabalho foram estabelecer padrões foliares, avaliar o estado nutricional do feijoeiro irrigado na região do Vale do Rio dos Bois, no Estado de Goiás, pelos métodos da faixa de suficiência (FS), da diagnose da composição nutricional (CND) e do sistema integrado de diagnose e recomendação (DRIS), bem como comparar os procedimentos de diagnóstico por meio de padrões nutricionais locais. Avaliaram-se a produtividade e a concentração foliar de 55 lavouras de feijoeiro na região do Vale do Rio dos Bois, entre 2010 e 2012. As amostras foram coletadas no estádio R5 (período de floração) e analisadas quanto aos teores totais de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn. As 55 amostras foram divididas em dois grupos, sendo o primeiro de baixa produtividade, com rendimento abaixo de 2.700 kg ha-1; e o segundo de alta produtividade, com rendimento igual ou acima de 2.700 kg ha-1, este último originando os padrões nutricionais. Normas CND e DRIS são mais indicadas para avaliação nutricional do feijoeiro irrigado comparativamente a FS estimada neste trabalho. Manganês, P e B são os elementos que mais limitam a produção nas lavouras de baixa produtividade na região do Vale do Rio dos Bois.
Ciclagem e balanço de nutrientes no sistema solo-planta em um plantio de Eucalyptus sp., no Distrito Federal
Authors: Gatto Alcides , Bussinguer Angela Pereira , Ribeiro Fabiana Campos , Azevedo Gileno Brito de , Bueno Maria Cristina , Monteiro Marina Morais , Souza Pierre Farias de
Published: July 2014

As espécies do gênero Eucalyptus são as mais plantadas no mundo, tornando-se solução para diminuir a pressão sobre as florestas nativas. Este trabalho objetivou avaliar a biomassa seca e sua distribuição nos diferentes compartimentos das árvores (folhas, galhos, casca, lenho e raízes), bem como examinar o conteúdo de macronutrientes dela e o balanço de nutrientes no sistema solo-planta, em um plantio de Eucalyptus urophylla x E. grandis, aos 60 meses de idade, na Fazenda Água Limpa, no Distrito Federal. Os dados foram obtidos de três árvores de eucalipto, que foram cubadas rigorosamente e tiveram as raízes escavadas até a profundidade de 60 cm. Esses dados foram submetidos à análise estatística pela correlação de Pearson. Grande parte da biomassa seca das árvores foi verificada no compartimento lenho (69,19 %), seguido de raízes (10,15 %), galhos (9,75 %), casca (6,06 %) e folhas (4,85 %). Os maiores teores de macronutrientes foram detectados nas folhas (N = 13,55 g kg-1; P = 1,33 g kg-1; K = 8,52 g kg-1; Ca = 7,12 g kg-1; Mg = 2,44 g kg-1; e S = 1,76 g kg-1), enquanto o lenho apresentou os menores (N = 1,73 g kg-1; P = 0,23 g kg-1; K = 0,34 g kg-1; Ca = 0,20 g kg-1; Mg = 0,03 g kg-1; e S = 0,43 g kg-1). A ordem dos conteúdos totais de macronutrientes verificada para a parte aérea foi: N > K > Ca >S > Mg > P, enquanto para as raízes, N > Ca > K > Mg > S > P. As raízes são responsáveis por acumular aproximadamente 11,90 % dos nutrientes contidos na biomassa das árvores; essa quantidade diminui com o aumento da profundidade. O balanço de nutrientes indica que P e S não são suficientes para um novo ciclo da floresta.
Congo grass grown in rotation with soybean affects phosphorus bound to soil carbon
Authors: Merlin Alexandre , He Zhenli L. , Rosolem Ciro Antonio
Published: July 2014

The phosphorus supply to crops in tropical soils is deficient due to its somewhat insoluble nature in soil, and addition of P fertilizers has been necessary to achieve high yields. The objective of this study was to examine the mechanisms through which a cover crop (Congo grass - Brachiaria ruziziensis) in rotation with soybean can enhance soil and fertilizer P availability using long-term field trials and laboratory chemical fractionation approaches. The experimental field had been cropped to soybean in rotation with several species under no-till for six years. An application rate of no P or 240 kg ha-1 of P2O5 had been applied as triple superphosphate or as Arad rock phosphate. In April 2009, once more 0.0 or 80.0 kg ha-1 of P2O5 was applied to the same plots when Congo grass was planted. In November 2009, after Congo grass desiccation, soil samples were taken from the 0-5 and 5-10 cm depth layer and soil P was fractionated. Soil-available P increased to the depth of 10 cm through growing Congo grass when P fertilizers were applied. The C:P ratio was also increased by the cover crop. Congo grass cultivation increased P content in the soil humic fraction to the depth of 10 cm. Congo grass increases soil P availability by preventing fertilizer from being adsorbed and by increasing soil organic P.
Macronutrient uptake, accumulation and export by the irrigated 'vitória' pineapple plant
Authors: Pegoraro Rodinei Facco , Souza Bruna Aparecida Madureira de , Maia Victor Martins , Silva Deivisson Ferreira da , Medeiros Ananias Costa , Sampaio Regynaldo Arruda
Published: July 2014

The nutritional state of the pineapple plant has a large effect on plant growth, on fruit production, and fruit quality. The aim of this study was to assess the uptake, accumulation, and export of nutrients by the irrigated 'Vitória' pineapple plant during and at the end of its development. A randomized block statistical design with four replications was used. The treatments were defined by different times of plant collection: at 270, 330, 390, 450, 510, 570, 690, 750, and 810 days after planting (DAP). The collected plants were separated into the following components: leaves, stem, roots, fruit, and slips for determination of fresh and dry matter weight at 65 ºC. After drying, the plant components were ground for characterization of the composition and content of nutrients taken up and exported by the pineapple plant. The results were subjected to analysis of variance, and non-linear regression models were fitted for the significant differences identified by the F test (p<0.01). The leaves and the stem were the plant components that showed the greatest accumulation of nutrients. For production of 72 t ha-1 of fruit, the macronutrient accumulation in the 'Vitória' pineapple exhibited the following decreasing order: K > N > S > Ca > Mg > P, which corresponded to 898, 452, 134, 129, 126, and 107 kg ha-1, respectively, of total accumulation. The export of macronutrients by the pineapple fruit was in the following decreasing order: K > N > S > Ca > P > Mg, which was equivalent to 18, 17, 11, 8, 8, and 5 %, respectively, of the total accumulated by the pineapple. The 'Vitória' pineapple plant exported 78 kg ha-1 of N, 8 kg ha-1 of P, 164 kg ha-1 of K, 14 kg ha-1 of S, 10 kg ha-1 of Ca, and 6 kg ha-1 of Mg by the fruit. The nutrient content exported by the fruits represent important components of nutrient extraction from the soil, which need to be restored, while the nutrients contained in the leaves, stems and roots can be incorporated in the soil within a program of recycling of crop residues.
Yield gains of coffee plants from phosphorus fertilization may not be generalized for high density planting
Authors: Valadares Samuel Vasconcelos , Neves Júlio César Lima , Novais Roberto Ferreira , Rosa Gustavo Nogueira Guedes Pereira , Martinez Hermínia Emília Prieto , Alvarez V. Víctor Hugo
Published: July 2014

Inconclusive responses of the adult coffee plant to phosphorus fertilization have been reported in the literature, especially when dealing with application of this nutrient in high density planting systems. Thus, this study was carried out for the purpose of assessing the response of adult coffee plants at high planting density in full production (in regard to yield and their biennial cycle/stability) to the addition of different sources and application rates of P in the Zona da Mata region of Minas Gerais, Brazil. The experiment with coffee plants of the Catucaí Amarelo 6/30 variety was carried out over four growing seasons. Treatments were arranged in a full factorial design [(4 × 3) + 1] consisting of four P sources (monoammonium phosphate, simple superphosphate, natural reactive rock phosphate from Algeria (Djebel-Onk), and FH 550®), three P rates (100, 200, and 400 kg ha-1 year-1 of P2O5), and an additional treatment without application of the nutrient (0 kg ha-¹ year-¹). A randomized block experimental design was used with three replicates. The four seasons were evaluated as subplots in a split plot experiment. The P contents in soil and leaves increased with increased rates of P application. However, there was no effect from P application on the yield and its biennial cycle/stability regardless of the source used over the four seasons assessed.
Effect of management systems and cover crops on organic matter dynamics of soil under vegetables
Authors: Souza Rodrigo Fernandes de , Figueiredo Cícero Célio de , Madeira Nuno Rodrigo , Alcântara Flávia Aparecida de
Published: July 2014

Vegetable production in conservation tillage has increased in Brazil, with positive effects on the soil quality. Since management systems alter the quantity and quality of organic matter, this study evaluated the influence of different management systems and cover crops on the organic matter dynamics of a dystrophic Red Latosol under vegetables. The treatments consisted of the combination of three soil tillage systems: no-tillage (NT), reduced tillage (RT) and conventional tillage (CT) and of two cover crops: maize monoculture and maize-mucuna intercrop. Vegetables were grown in the winter and the cover crops in the summer for straw production. The experiment was arranged in a randomized block design with four replications. Soil samples were collected between the crop rows in three layers (0.0-0.05, 0.05-0.10, and 0.10-0.30 m) twice: in October, before planting cover crops for straw, and in July, during vegetable cultivation. The total organic carbon (TOC), microbial biomass carbon (MBC), oxidizable fractions, and the carbon fractions fulvic acid (C FA), humic acid (C HA) and humin (C HUM) were determined. The main changes in these properties occurred in the upper layers (0.0-0.05 and 0.05-0.10 m) where, in general, TOC levels were highest in NT with maize straw. The MBC levels were lowest in CT systems, indicating sensitivity to soil disturbance. Under mucuna, the levels of C HA were lower in RT than NT systems, while the C FA levels were lower in RT than CT. For vegetable production, the C HUM values were lowest in the 0.05-0.10 m layer under CT. With regard to the oxidizable fractions, the tillage systems differed only in the most labile C fractions, with higher levels in NT than CT in the 0.0-0.05 m layer in both summer and winter, with no differences between these systems in the other layers. The cabbage yield was not influenced by the soil management system, but benefited from the mulch production of the preceding maize-mucuna intercrop as cover plant.
Rice husk ash as corrective of soil acidity
Authors: Islabão Gláucia Oliveira , Vahl Ledemar Carlos , Timm Luís Carlos , Paul Donald Luiz , Kath Aline Hernandez
Published: July 2014

Rice husk ash (RHA) is a by-product from the burning of rice husk that can have favorable effects on the soil in terms of acidity correction. The objectives of this study were to determine the effective calcium carbonate equivalent (ECC) of RHA under field conditions, and establish technical criteria as a basis for estimating the overall ECC of RHA. The 12 treatments of the experiment consisted of 10 RHA dosages (0, 10, 20, 30, 40, 60, 80, 100, 120, and 140 Mg ha-1) and two references, one of which was an absolute control (AC) and the other a plot limed and fertilized according to official recommendations (recommended fertilization - RF). The soil was sampled twice (15 and 210 days after incorporating RHA), in the layers 0.00-0.10 and 0.10-0.20 m, to determine the pH(H2O) and base saturation (V%). The ECC and neutralizing value (NV) of RHA were also determined. The results showed that RHA neutralizes soil acidity, in a faster reaction than conventional limestone, despite a low ECC (around 3 %).
Hygroscopicity and ammonia volatilization losses from nitrogen sources in coated urea
Authors: Faria Letícia de Abreu , Nascimento Carlos Antonio Costa do , Ventura Barbara Paquier , Florim Gabriela Perissinotto , Luz Pedro Henrique de Cerqueira , Vitti Godofredo Cesar
Published: July 2014

Hygroscopic fertilizers tend to absorb moisture from the air and may have undesirable characteristics such as moistness, clumping and lower fluidity, hampering the application. The increasing use of urea is due to its numerous advantages, although this nitrogen (N) source is highly susceptible to volatilization losses, particularly when applied to the soil surface of management systems with conservation of crop residues. The volatilization losses can be minimized by slow or controlled-release fertilizers, with controlled water solubility of the urea-coating materials; and by stabilized fertilizers, which prolong the period during which N remains in the amide or ammonia forms by urease inhibitors. This study evaluated the hygroscopicity of and ammonia volatilization from urea coated with boric acid and copper sulfate or with sulfur. The hygroscopicity of the sources was evaluated over time after exposure to five levels of relative humidity (RH) and volatilization evaluated after application to the soil surface covered with sugarcane trash. Ammonium nitrate has a low potential for volatilization losses, but is highly hygroscopic. Although coating with boric acid and copper sulfate or elemental sulfur reduced the critical humidity level of urea, the delay in the volatilization process is a potential positive factor.
Pig slurry and nutrient accumulation and dry matter and grain yield in various crops
Authors: Lourenzi Cledimar Rogério , Ceretta Carlos Alberto , Brunetto Gustavo , Girotto Eduardo , Tiecher Tadeu Luis , Vieira Renan Costa Beber , Cancian Adriana , Ferreira Paulo Ademar Avelar
Published: July 2014

Pig slurry (PS) represents an important nutrient source for plants and using it as fertilizer makes greater nutrient cycling in the environment possible. The aim of this study was to assess how PS application over a period of years can affect grain yield, dry matter production and nutrient accumulation in commercial grain and cover crops. The experiment was carried out in an experimental area of the Universidade Federal de Santa Maria, in Santa Maria, RS, Brazil, from May 2000 to January 2008. In this period, 19 grain and cover crops were grown with PS application before sowing, at rates of 0, 20, 40 and 80 m³ ha-1. The highest PS rate led to an increase in nutrient availability over the years, notably of P, but also of nutrients that are potentially toxic to plants, especially Cu and Zn. The apparent recovery of nutrients by commercial grain and cover crops decreased with the increasing number of PS applications to the soil. Accumulated dry matter production of the crops and maize grain yield were highest at an annual application rate of 80 m³ ha-1 PS. However, common bean yield increased up to 20 m³ ha-1 PS, showing that the crop to be grown should be considered to define the application rate.
Sensoriamento remoto na determinação de atributos de um nitossolo sob aplicação de vinhaça
Authors: Martins Juliano Araujo , Fiorio Peterson Ricardo , Demattê José A. M. , Miranda Jarbas Honorio de , Lelis Neto João Alberto
Published: July 2014

O sensoriamento remoto vem sendo utilizado na avaliação de características químicas e físicas dos solos, como fonte de informação rápida, não destrutiva e de baixo custo, podendo assim auxiliar no gerenciamento de passivos ambientais. Nesse sentido, este trabalho teve por objetivo verificar o potencial da utilização de dados hiperespectrais na determinação de algumas propriedades de um solo submetido a diferentes aplicações de doses de vinhaça, utilizando dados espectrais oriundos de amostras em condições de campo e de terra fina seca em estufa. O experimento, delineado em blocos ao acaso constou de seis tratamentos e quatro repetições, sendo os tratamentos: 1, sem vinhaça; 2, fertirrigado com químicos; e 3, 4, 5 e 6, com aplicação de, respectivamente, 150, 300, 600 e 900 m³ ha-1 de vinhaça. Foram gerados modelos para predição de alguns atributos químicos e físicos do solo para os dois tipos de amostras, a partir de curvas espectrais na região do visível e infravermelho próximo. Para determinação da granulometria, os modelos não foram influenciados pelo tipo de amostra utilizada e foram classificados como "aceitáveis" a "bons" (R² entre 0,7 e 0,9). Em relação aos atributos químicos, foram gerados modelos com capacidade de diferenciação apenas entre altas e baixas concentrações (R² entre 0,50 e 0,65) para os atributos pH, matéria orgânica, H+Al e capacidade de troca catiônica, sendo os gerados para terra fina seca em estufa em alguns casos melhores que os para amostras em condições de campo.
Forms of phosphorus in an oxisol under different soil tillage systems and cover plants in rotation with maize
Authors: Carvalho Arminda Moreira de , Bustamante Mercedes Maria da Cunha , Almondes Zayra Azeredo do Prado , Figueiredo Cícero Célio de
Published: July 2014

Phosphorus fractions play a key role in sustaining the productivity of acid-savanna Oxisols and are influenced by tillage practices. The aim of this study was to quantify different P forms in an Oxisol (Latossolo Vermelho-Amarelo) from the central savanna region of Brazil under management systems with cover crops in maize rotation. Three cover crops (Canavalia brasiliensis, Cajanus cajan (L.), and Raphanus sativus L.) were investigated in maize rotation systems. These cover crops were compared to spontaneous vegetation. The inorganic forms NaHCO3-iP and NaOH-iP represented more than half of the total P in the samples collected at the depth of 5-10 cm during the rainy season when the maize was grown. The concentration of inorganic P of greater availability (NaHCO3-iP and NaOH-iP) was higher in the soil under no-tillage at the depth of 5-10 cm during the rainy season. Concentrations of organic P were higher during the dry season, when the cover crops were grown. At the dry season, organic P constituted 70 % of the labile P in the soil planted to C. cajan under no-tillage. The cover crops were able to maintain larger fractions of P available to the maize, resulting in reduced P losses to the unavailable pools, mainly in no-tillage systems.
Carbono e nitrogênio nas frações granulométricas da matéria orgânica do solo, em sistemas de culturas sob plantio direto
Authors: Winck Bruna Raquel , Vezzani Fabiane Machado , Dieckow Jeferson , Favaretto Nerilde , Molin Rudimar
Published: July 2014

A qualidade do solo em plantio direto está relacionada ao sistema de culturas e pode ser avaliada pelo teor de matéria orgânica particulada (>53 ∝m), em razão da funcionalidade que essa fração proporciona ao solo e à sua sensibilidade às diferenças de manejo. Visando estudar a qualidade do solo em sistemas de culturas em plantio direto, este trabalho foi conduzido em experimento de longa duração (21 anos) em Latossolo Vermelho distrófico típico nos Campos Gerais do Paraná. Seis sistemas de culturas foram avaliados, em que trigo-TR (Triticum aestivum L.), soja-SO (Glycine max L.), milho-MI (Zea mays L.), aveia-preta-AV, para cobertura (Avena strigosa Schreb.), ervilhaca-ER, para cobertura (Vicia villosa Roth); azevém-AZ, para feno (Lolium multiflorum Lam.); ou alfafa-AL, para feno (Medicago sativa L.) compuseram os seguintes sistemas: TR-SO (referência), ER-MI-AV-SO-TR-SO, ER-MI-TR-SO, AV-MI-TR-SO, AZ-MI-AZ-SO e AL-MI (milho a cada três anos). Os estoques de carbono orgânico total (COT), nitrogênio total (NT) e de C e N na matéria orgânica (MO) particulada (>53 µm) e associada aos minerais (<53 µm) foram determinados em 0-5, 5-10 e 10-20 cm. O sistema semiperene AL-MI apresentou os maiores estoques de COT e NT na camada de 0-20 cm (63,6 Mg ha-1 COT e 4,6 Mg ha-1 NT), com incrementos anuais de 0,23 Mg ha-1 COT e 0,03 Mg ha-1 NT, em relação ao sistema TR-SO. O sistema AL-MI também teve os maiores estoques de C e N na MO particulada nessa camada (12,5 e 0,91 Mg ha-1, respectivamente), por causa da maior adição de fitomassa pelas raízes e a proteção física dos resíduos orgânicos. Os menores estoques de COT e NT na camada 0-20 cm ocorreram no sistema ER-MI-TR-SO (57,8 Mg ha-1 COT e 4,03 Mg ha-1 NT), sem apresentar incremento anual em relação ao sistema TR-SO. Os estoques de C e N na MO particulada foram de 10,4 e 0,67 Mg ha-1, respectivamente. Essa tendência repetiu-se para as camadas individuais, com diferença significativa entre os sistemas na camada de 0-5 cm e não significativa, para as de 5-10 e 10-20 cm. Na média dos sistemas, a MO particulada contribuiu em torno de 30 % para o estoque total de C na camada 0-5 cm. Rotação de culturas com espécies que tenham sistema radicular ativo por mais tempo, como o sistema semiperene AL-MI, tem potencial de incrementar o estoque total de C e N, especialmente da fração MO particulada, proporcionando funcionalidade ao solo e, consequentemente, qualidade.