64 research outputs found

    Additives incorporated into urea to reduce nitrogen losses after application to the soil.

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    The objective of this work was to develop urea-based fertilizers with internal incorporation of urease inhibitors and other additives in the granule. The effects of the incorporation of NBPT, copper (Cu+2), boric acid (H3BO3), elemental sulphur (Sº), and a clay mineral from the zeolite group in powder urea - with ten different combinations of these additives - were evaluated as to N losses by volatilization and leaching. The losses in laboratory-developed formulations were compared with those of commercial fertilizers coated with the same additives (Super N, FH Nitro Mais, and FH Nitro Gold). The evaluations were made in greenhouse conditions, using a Ultisol accommodated in PVC columns. Nitrate and ammonium leaching was evaluated in the solution percolated through the soil columns. Ammonia volatilization was measured with a semi-open static chamber. The incorporation of urease inhibitors (NBPT, H3BO3, and Cu+2) into the urea granules was efficient to reduce N volatilization. Ammonia volatilization in the laboratory-developed ureas was lower than in commercial fertilizers coated with the same additives, while ammonium sulfate losses by leaching were similar. The addition of zeolite does not reduce N volatilization. Mineral N leaching in the soil profile is not affected by urease inhibitors.Título em português: Aditivos incorporados à ureia para reduzir perdas de nitrogênio após aplicação ao solo

    New insights into potocki-shaffer syndrome: Report of two novel cases and literature review

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    Potocki-Shaffer syndrome (PSS) is a rare non-recurrent contiguous gene deletion syndrome involving chromosome 11p11.2. Current literature implies a minimal region with haploinsufficiency of three genes, ALX4 (parietal foramina), EXT2 (multiple exostoses), and PHF21A (craniofacial anomalies, and intellectual disability). The rest of the PSS phenotype is still not associated with a specific gene. We report a systematic review of the literature and included two novel cases. Because deletions are highly variable in size, we defined three groups of patients considering the PSS-genes involved. We found 23 full PSS cases (ALX4, EXT2, and PHF21A), 14 cases with EXT2-ALX4, and three with PHF21A only. Among the latter, we describe a novel male child showing developmental delay, café-au-lait spots, liner postnatal overgrowth and West-like epileptic encephalopathy. We suggest PSS cases may have epileptic spasms early in life, and PHF21A is likely to be the causative gene. Given their subtle presentation these may be overlooked and if left untreated could lead to a severe type or deterioration in the developmental plateau. If our hypothesis is correct, a timely therapy may ameliorate PSS phenotype and improve patients’ outcomes. Our analysis also shows PHF21A is a candidate for the overgrowth phenotype

    Qualidade físico-química de frutos de morangueiro em função da adubação potássica

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    A melhoria das características do morango é uma forma de garantir melhor aceitação pelo mercado consumidor e melhor rendimento no processamento e industrialização. Nesse contexto, a nutrição e adubação do morangueiro são fatores importantes a serem considerados para melhorar a produtividade, conservação  pós-colheita e propriedades físico-químicas do fruto. O presente trabalho teve como objetivo avaliar as características físico-químicas de frutos de duas cultivares de morangueiro, em função da adubação com diferentes doses de fertilizante potássico. Os tratamentos foram quatro doses de K2O (0,200, 400 e 600 kg ha-1) e duas cultivares de morangueiro (Camarosa e Sweet Charlie) produzidas em cultivo protegido. O delineamento experimental foi em blocos casualizados em esquema fatorial 4x2, com 3 repetições. Foram avaliados os teores de sólidos solúveis, pH, massa seca e acidez titulável nos frutos. Para as análises foram amostrados 20 frutos de cada parcela, colhidos e armazenados a baixas temperaturas (-5 oC). Os maiores teores de massa seca nos frutos de morango da cultivar Camarosa foram obtidos na dosagem de 332,5 kg ha-1 de K2O. A cultivar Sweet Charlie respondeu com maior acúmulo de massa seca e maiores teores de sólidos solúveis até a dose de 479 kg ha-1. Conforme esses resultados, doses de fertilizante potássico entre 300 e 500 kg ha-1 são consideradas ideais para a qualidade dos frutos do morangueiro

    Distribution of Soil Phosphorus Fractions as a Function of Long-Term Soil Tillage and Phosphate Fertilization Management.

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    The forms in which phosphorus (P) accumulates in soils are dependent on management practices, fertilizer sources, and methods of application, which may promote distinct P solubility and plant uptake. We aimed here to evaluate how soil tillage and phosphate fertilization strategies affected soil P fractions over 17 years and to identify best management practices for improving labile P fractions. The experiment was conducted in a very clayey Rhodic Ferralsol (Oxisol) with initially very low P availability, during 17 years under soybean and corn, fertilized with 35 kg P ha?1 year?1 . Treatments were two soil management systems (CT-conventional tillage and NT-no-till) and four phosphate fertilization strategies (TSP ? triple superphosphate or RRP ? reactive rock phosphate, applied to the crop furrow or broadcast). Soil samples were taken at five depth layers, and organic (Po), inorganic (Pi), and total P (Pt) were determined by Hedley?s sequential fractionation. CT resulted in a more homogeneous distribution of Pi fractions throughout the soil profile, while under NT there was a steep depth gradient characterized by Pi accumulation in the fertilizer application zone. NT resulted in accumulation of Pi in more labile fractions and higher accumulation of Po physically protected by aggregation, both compared to CT. Also, under NT with RRP, there was a great accumulation of Pi associated with calcium (HCl Pi) compared to TSP, especially when the fertilizer was broadcast applied. An accumulation of Po down to 20 cm (CT) and 10 cm (NT) was also detected, compared to Cerrado natural soil. NT and RRP positively affected legacy P fractions and can be recommended as strategies to improve P fertilizer use efficiency. Keywords: no-tillage, P fractionation, legacy P, P source, P distributio

    Expanding the stdpopsim species catalog, and lessons learned for realistic genome simulations

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    Simulation is a key tool in population genetics for both methods development and empirical research, but producing simulations that recapitulate the main features of genomic datasets remains a major obstacle. Today, more realistic simulations are possible thanks to large increases in the quantity and quality of available genetic data, and the sophistication of inference and simulation software. However, implementing these simulations still requires substantial time and specialized knowledge. These challenges are especially pronounced for simulating genomes for species that are not well-studied, since it is not always clear what information is required to produce simulations with a level of realism sufficient to confidently answer a given question. The community-developed framework stdpopsim seeks to lower this barrier by facilitating the simulation of complex population genetic models using up-to-date information. The initial version of stdpopsim focused on establishing this framework using six well-characterized model species (Adrion et al., 2020). Here, we report on major improvements made in the new release of stdpopsim (version 0.2), which includes a significant expansion of the species catalog and substantial additions to simulation capabilities. Features added to improve the realism of the simulated genomes include non-crossover recombination and provision of species-specific genomic annotations. Through community-driven efforts, we expanded the number of species in the catalog more than threefold and broadened coverage across the tree of life. During the process of expanding the catalog, we have identified common sticking points and developed the best practices for setting up genome-scale simulations. We describe the input data required for generating a realistic simulation, suggest good practices for obtaining the relevant information from the literature, and discuss common pitfalls and major considerations. These improvements to stdpopsim aim to further promote the use of realistic whole-genome population genetic simulations, especially in non-model organisms, making them available, transparent, and accessible to everyone

    Adubos orgânicos e organominerais como alternativa sustentável para a cultura do milho (Zea mays L.).

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    Mineral fertilizers, in addition to being costly when misused, can be aggressive to the soil and the environment. For this reason, it is necessary to evaluate other sources of nutrients for plants. For this purpose, the experiment was installed under field conditions, with the objective of evaluating the efficiency of bat guano and organomineral organic fertilizers, resulting from the mixture based on nitrogen, phosphorus and potassium (NPK), in formula-12-24-12, on the development and yield of corn (Zea mays L.), submitted to a completely randomized block design, with 4 treatments and 4 repetitions. The treatments were mineral fertilizer (NPK, 12-24-12), bat guano, organomineral (NPK and bat guano), and the control. The results show that the bat guano provided the greatest increase in plant height and number of grains, while the largest increments in stem diameter, number of leaves, cob weight, grain weight, and higher yield, were obtained by the organomineral. These results have been achieved, despite the fact that organic fertilizers have low concentrations of NPK, when complemented with mineral fertilization, they promote positive effects on plants, since they make better use of nutrients through the timing of release throughout their development. It was concluded that organic and organomineral fertilizers can be used as a sustainable alternative to increase yields in the corn crop in replacement of mineral fertilizers.Los fertilizantes minerales, además de ser costosos cuando se usan incorrectamente, pueden ser agresivos para el suelo y el medio ambiente. Por esta razón, es necesario evaluar otras fuentes de nutrientes para las plantas. Para este propósito, el experimento se instaló en condiciones de campo, con el objetivo de evaluar la eficiencia del guano de murciélago orgánico y los fertilizantes organominerales, como resultado de la mezcla de guano y fertilizante complejo a base de nitrógeno, fósforo y potasio. (NPK), en la fórmula 12-24-12, sobre el desarrollo y rendimiento del cultivo de maíz (Zea mays L.), sometido a un diseño experimental de bloques completos al azar, con 4 tratamientos y 4 repeticiones. Los tratamientos fueron fertilizante mineral (NPK, 24-12-12), guano de murciélago, organomineral y el control. Los resultados muestran que el guano de murciélago proporcionó el mayor aumento en la altura de la planta y el número de granos por mazorca, mientras que los mayores incrementos en el diámetro del tallo, el número de hojas, el peso de la mazorca, el peso del grano, así como un mayor rendimiento por área , fueron obtenidos por el organomineral. Estos resultados se lograron, a pesar del hecho de que los fertilizantes orgánicos tienen bajas concentraciones de NPK, cuando se complementan con la fertilización mineral, promueven efectos positivos en las plantas, ya que hacen un mejor uso de los nutrientes a través del momento de la liberación a lo largo de su desarrollo. Se concluyó que los fertilizantes minerales orgánicos y orgánicos pueden usarse como una alternativa sostenible para aumentar los rendimientos en el cultivo de maíz en reemplazo de los fertilizantes minerales.Os fertilizantes minerais para além de apresentarem custos onerosos, quando mal empregues, podem ser agressivos aos solos e ao meio ambiente. Por este motivo, é necessária a avaliação de outras fontes de nutrientes para as plantas. Para o efeito, foi instalado o experimento em condições de campo, com o objetivo de avaliar a eficiência dos adubos orgânicos a base de guano de morcego e o organomineral, resultante da mistura do guano e do fertilizante complexo a base de nitrogênio, fosforo e potássio (NPK), na fórmula-12-24-12, sobre o desenvolvimento e rendimento da cultura do milho (Zea mays L.), submetidas em desenho experimental de blocos completos casualizados, com 4 tratamentos e 4 repetições. Os tratamentos foram, o adubo mineral (NPK, 12-24-12), o guano de morcego, o organomineral, e a testemunha. Os resultados mostram que o guano de morcego proporcionou maior incremento na altura da planta e número de grãos por espiga, enquanto que os maiores incrementos do diâmetro do caule, número de folhas, peso da espiga, peso dos grãos, assim como maior rendimento por área, foram obtidos pelo organomineral. Estes resultados foram alcançados, apesar dos adubos orgânicos apresentarem baixas concentrações de NPK, quando complementados com adubação mineral, promovem efeitos positivos às plantas, uma vez que estas aproveitam melhor os nutrientes através do sincronismo de liberação ao longo do seu desenvolvimento. Concluiu-se que, os adubos orgânicos e organominerais podem ser utilizados como alternativa sustentável para o aumento dos rendimentos na cultura do milho em substituição dos adubos minerais
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