1,039 research outputs found
Evaluation of Stabilized Fertilizer and Crop Canopy Sensors as Next-Generation Nitrogen Management Technologies in Irrigated Corn
Nitrogen (N) is often the most limiting nutrient to corn. Once applied to the field, N can be lost through different pathways, which contributes to low N use efficiency (NUE) by plants. Increases in NUE and decreases in N losses can be potentially achieved by using management options that allow a better synchrony between N supply and demand, such as stabilized fertilizers, and spatially-variable sensor-derived in-season N application. Three studies were conducted in order to assess the effects of different stabilized fertilizers and crop canopy sensors on irrigated corn yield. The first study evaluated the effect of urease inhibitor on ammonia losses and corn grain yield. The use of urease inhibitors significantly reduced ammonia volatilization losses by 21 to 62%, but this did not translate into higher corn yields. The second study evaluated the effect of various management practices along with the use of a nitrification inhibitor and their interaction with weather on irrigated corn grain yield over 28 yrs. The use of a nitrification inhibitor had negative, neutral, and positive effects on corn grain yield, and the magnitude of its effect was less than other management practices. The most important weather variables in explaining different yield responses were year- yield potential, precipitation volume and distribution, and air temperature. The third study compared active and passive crop canopy sensors in assessing corn N deficiency and the accuracy of recommended side-dress N rates compared to the economic optimum N rate. This study included eight field studies using different N fertilizer rates and the use of both active and passive crop canopy sensor during the mid-vegetative growth stage in corn. Active and passive sensors recommended comparable side- dress N rates given proper selection of algorithm inputs. Their recommendation was partially or fully accurate in four of six studies. Both stabilized fertilizers and crop canopy sensors are important management tool options for producers, and an understanding of their strengths and weaknesses is needed to guide proper adoption decisions.
Advisor: Richard B. Ferguso
N fertilizer source and placement impacts nitrous oxide losses, grain yield and N use efficiency in no-till corn
Master of ScienceDepartment of AgronomyCharles W. RiceAgricultural lands receiving N inputs are considered the primary source of N2O, a potent greenhouse gas. N fertilizer management has shown variable effects on both N2O losses and corn grain yield. The objectives of this study were to assess the impact of N source and placement on N2O emissions, fertilizer-induced emission factor (FIEF), corn grain yield, yield-scaled N2O emissions (YSNE) and N fertilizer recovery efficiency (NFRE). The experiment was conducted from 2013 through 2014 at the Agronomy North Farm located at Kansas State University, Manhattan, KS. The soil was a moderately well-drained Kennebec silt loam. The treatments were broadcast urea (BC-Urea), broadcast urea ammonium nitrate (UAN) (BC-UAN), broadcast coated urea (BC-CU), surface-band UAN (SB-UAN), subsurface-band UAN (SSB-UAN), subsurface-band UAN + nitrification inhibitor (SSB-UAN+I) and a 0 N control. In 2013, SSB- UAN emitted significantly more N2O (2.4 kg N2O-N ha-1), whereas control (0.3 kg ha-1) and BC- UAN (0.6 kg ha-1) emitted the least. In 2014, most treatments emitted between 3.3 and 2.5 kg N2O-N ha-1. Only SSB-UAN+I (1.03 kg ha-1) and control (0.26 kg ha-1) were significantly lower. The use of a nitrification inhibitor decreased N2O emissions by 62% and 55% in 2013 and 2014, respectively. BC treatments had cumulative emissions significantly higher in 2014 compared to 2013. Only SSB-UAN+I had a significantly lower FIEF (0.4%), and 2013 FIEF (0.68%) was significantly lower than that of 2014 (1.38%). In 2013, banded treatments had significantly higher grain yields (from 9.1 to 10.5 Mg ha-1), whereas in 2014 fewer differences among N treatments were observed, ranging from 7.2 to 8.6 Mg ha-1. Banded treatments had significantly lower grain yields in 2014 compared to 2013. Only BC-UAN and SSB-UAN+I had significantly lower YSNE, and 2013 had lower YSNE than 2014. In 2013, SSB-UAN had the greatest NFRE, whereas BC treatments had the lowest. In 2014, N treatments did not differ in NFRE. SSB-UAN
and SSB-UAN+I had significantly lower NFRE values in 2014 compared to 2013. Fertilizer source and placement have the potential to mitigate N2O emissions and promote high yields and NFRE in corn, however, the response is dependent on the rainfall pattern after fertilizer application. The option of banding UAN without any additive promoted higher N2O losses on a year when precipitation was well distributed, but also enhanced grain yield and NFRE. On the other hand, under the same precipitation conditions, broadcasting N fertilizer promoted lower N2O losses, grain yield and NFRE, but those were all improved in a wet year. Therefore, the subsurface band placement would be the best option under a normal year, whereas broadcasting fertilizer would be the best option under a wetter year. Further, the use of NI with subsurface band UAN provides the most sustainable option, since the NI decreased N2O losses compared to UAN alone in both years. Further research should evaluate N source and placement combinations under different environments in order to better understand how they impact crop performance and the negative environmental aspects of N fertilization. It is important to test those treatments under different precipitation scenarios and look for trends that indicate the best N management option at the local level
Root and Shoot Contribution to Carbon and Nitrogen Inputs in the Topsoil Layer in No-Tillage Crop Systems under Subtropical Conditions
Recycling of carbon (C) and nitrogen (N) from plants into soils is decisive for maintaining soil organic matter and soil fertility. Therefore, we quantified plant biomass and C and N in the shoots and roots from the topsoil layer for a wide range of annual crops grown under subtropical conditions. We grew 26 species, 13 main crops, and 13 cover crops, in the field in standard sowing arrangements. Root biomass was recovered from the 0.00-0.20 m soil layer at flowering, and shoot biomass was measured at flowering for all crops and at maturity only for the main crops. Root dry matter (DM) exhibited an average of 14.9 ± 5.7 % of the total shoot biomass at flowering, and the mean shoot DM to root DM ratio was 6.9 (2.8-15.0) for the 26 crops considered. Leguminous species had less root DM (0.5 to 1.0 Mg ha-1) than grass species (1.1 to 2.3 Mg ha-1). The shoot C to root C ratio varied consistently with DM, while the root N to shoot N ratio varied considerably among species. Proportionally more biomass, C, and N was allocated to the root systems of grasses (Poaceae species) than non-grass species (especially Fabaceae species). The findings of this study contribute to designing rotations to include species that promote cycling of N and have high potential for adding C to the soil through roots. In this sense, the use of intercropped grasses and legumes is a promising strategy, especially for cover crops
Root and Shoot Contribution to Carbon and Nitrogen Inputs in the Topsoil Layer in No-Tillage Crop Systems under Subtropical Conditions
Recycling of carbon (C) and nitrogen (N) from plants into soils is decisive for maintaining soil organic matter and soil fertility. Therefore, we quantified plant biomass and C and N in the shoots and roots from the topsoil layer for a wide range of annual crops grown under subtropical conditions. We grew 26 species, 13 main crops, and 13 cover crops, in the field in standard sowing arrangements. Root biomass was recovered from the 0.00-0.20 m soil layer at flowering, and shoot biomass was measured at flowering for all crops and at maturity only for the main crops. Root dry matter (DM) exhibited an average of 14.9 ± 5.7 % of the total shoot biomass at flowering, and the mean shoot DM to root DM ratio was 6.9 (2.8-15.0) for the 26 crops considered. Leguminous species had less root DM (0.5 to 1.0 Mg ha-1) than grass species (1.1 to 2.3 Mg ha-1). The shoot C to root C ratio varied consistently with DM, while the root N to shoot N ratio varied considerably among species. Proportionally more biomass, C, and N was allocated to the root systems of grasses (Poaceae species) than non-grass species (especially Fabaceae species). The findings of this study contribute to designing rotations to include species that promote cycling of N and have high potential for adding C to the soil through roots. In this sense, the use of intercropped grasses and legumes is a promising strategy, especially for cover crops
Microbial and enzymatic activities in the soil after application of retorted oil shale
O objetivo deste trabalho foi avaliar o efeito da aplicação de doses crescentes de xisto retortado (XR) sobre características biológicas indicadoras da qualidade do solo. Foram realizados experimentos, em Argissolo Vermelho distrófico arênico, em condições de laboratório e de campo. Em laboratório, os tratamentos consistiram da aplicação ao solo de sete diferentes doses de XR (0, 300, 450, 600, 750, 1.500 e 3.000 kg ha-1). Em campo, os tratamentos foram compostos por quatro diferentes doses de XR (0, 750, 1.500, 3.000 kg ha-1) combinadas à adubação mineral recomendada, avaliados em dois cultivos de feijão (Phaseolus vulgaris L.), no sistema plantio direto. Avaliaram-se: a evolução de CO2, o carbono da biomassa microbiana (CBM), a atividade enzimática do solo e o teste de ecotoxicidade. A aplicação de doses crescentes de XR melhorou a atividade microbiológica do solo, por reduzir a emissão de CO2 sem causar variação no CBM e sem provocar impactos negativos sobre a atividade enzimática do solo. Os resultados obtidos com as enzimas em condições de campo, após duas aplicações de XR, aliados aos de CBM, do quociente metabólico (qCO2) e do teste ecotoxicológico, em condições de laboratório, indicam que o uso do XR não provoca a degradação biológica do solo.The objective of this study was to assess the effect of increasing doses of retorted oil shale (ROS) application on the biological property indicators of soil quality. Experiments were carried out, under field and laboratory conditions, on a Hapludalf soil. In the laboratory, the treatments consisted of the application of seven different ROS rates (0, 300, 450, 600, 750, 1,500 and 3,000 kg ha-1) to the soil. In the field, the treatments were composed by four different ROS rates (0, 750, 1,500 and 3,000 kg ha-1) combined with the recommended mineral fertilizer rate, evaluated in two croppings of common bean (Phaseolus vulgaris L.), under no-till system. CO2 evolution, microbial biomass carbon (MBC), soil enzyme activity and the ecotoxicity test were evaluated. Application of increasing ROS rates improved the soil microbial activity by decreasing CO2 emission and causing no variations in MBC nor negative impacts on the soil enzymatic activity. The results obtained with the enzymes under field conditions, after two ROS applications, allied to MBC results, and to the metabolic quocient (qCO2) and to the ecotoxicity test, under laboratory conditions, show that the use of ROS cause no soil biological degradation
Secukinumab demonstrates improvements in absolute and relative psoriasis area severity indices in moderate-to-severe plaque psoriasis: results from a European, multicentric, retrospective, real-world study
AbstractObjective: This European, multicentric, retrospective study aimed to collect data on secukinumab effectiveness in a real-world setting.Research design and methods: All psoriatic patients st..
Manejo das urgências subjetivas nas instituições: que lugar para o serviço-escola?
Neste artigo pretende-se discutir a problemática do manejo da urgência subjetiva nas instituições, apoiando-se em uma investigação em andamento no serviço-escola de uma universidade pública. Interroga-se a urgência generalizada, marca de nossos tempos, para situar as coordenadas do manejo da angústia presente nas demandas por assistência em saúde mental dirigidas às instituições. Articula-se, a partir das referências teórico-clínicas dentro da psicanálise de orientação lacaniana, a prática do manejo das urgências em diversos dispositivos de saúde. Pretende-se circunscrever a partir dessa elaboração, o duplo pertencimento dos serviços-escola: lugar de formação e instituição que, de alguma forma, participa da rede de saúde mental
ESTUDO DA QUALIDADE DAS ÁGUAS DO RIO MAROMBAS (SC/BRASIL), UTILIZANDO PARÂMETROS FÍSICO-QUÍMICOS E BIOENSAIOS.
O presente trabalho propôs realizar estudos preliminares de avaliação da qualidade das águas do Rio Marombas (SC-Brasil), utilizando parâmetros físico-químicos e bioensaios. Amostras de águas do Rio Marombas foram coletadas em 3 pontos e realizada a determinação de pH, oxigênio dissolvido (OD), análise de agroquímicos, hidrocarbonetos policíclicos aromáticos (HPA’s), compostos orgânicos voláteis (COV’s) e bifenilas policloradas (PCB’s). Foram executados ensaios de toxicidade aguda (CL50) em microcrustáceos Artemia sp. e de fitotoxicidade em Allium cepa L. avaliada pela inibição de crescimento e peso de raízes e pelos biomarcadores de estresse oxidativo glutationa reduzida (GSH) e peroxidação lipídica. Os resultados dos parâmetros físico-químicos indicaram que os valores de pHestiveram compatíveis com padrões previstos pela legislação. Foi constatada a presença dos agroquímicos metomil nos Pontos 1 e 2 e metconazol no Ponto 1. Os bioensaios revelaram que não houve toxicidade em Artemia sp. e ausência de inibição de crescimento e peso de raízes em Allium cepa L. A concentração de GSH estava significativamente aumentada no Ponto 3 quando comparada ao Ponto 1 e ao controle negativo. Não foi observada diferença significativa na avaliação de peroxidação lipídica entre os diferentes grupos. Esses resultados indicam que as águas do Rio Marombas podem estar sendo contaminadas por agroquímicos, sugerindo a necessidade de implementação de sistema de monitoramento periódico de sua qualidade.Palavras-chave: rio Marombas; parâmetros físico-químicos; bioensaiosSTUDY OF WATER QUALITY FROM THE MAROMBAS RIVER (SC/BRAZIL) USING THE PHYSICOCHEMICAL PARAMETERS AND BIOASSAYS.ABSTRACTThe present study proposed preliminary studies assessing the quality of water from the river Marombas (SCBrazil) using the physicochemical parameters and bioassays. Samples of water from Marombas river were collected at three points and it was determined the pH, dissolved oxygen (DO), concentration of agrochemicals, polycyclic aromatic hydrocarbons (PAH’s), volatile organic compounds (VOC`s) and polychlorinated biphenyls (PCB´s). Acute toxicity tests (LC50) were carried out in microcrustaceans Artemia sp. and phytotoxicity tests in Allium cepa L. assessed through theinhibition of growth and weight of roots and by biomarkers of oxidative stress reduced glutathione (GSH) and lipid peroxidation. The results of physicochemical parameters indicated that the pH values were consistent with standards established by the legislation. It could be observed the presence of the agrochemicals methomyl in Points 1 and 2 and metconazole in Point 1. The bioassays showed absence of the acute toxicity in Artemia sp. and there was no inhibition of growth and weight of roots in Allium cepa L. The concentration of GSH was significantly increased (P<0.05) in Point 3 when compared to Point 1 and the negative control. No significant difference could be observed in the evaluation of lipid peroxidation between different groups. These results demonstrate that the water of the Marombas river is contaminated by agrochemicals, suggesting the necessity of implementing a system of monitoring its quality.Key words: Marombas river, physicochemical parameters, bioassay
O câncer e a criança: um impacto familiar
The aim of this work is a bibliographic review concerning the children living with cancer and their family, in order to identify the themes that have been already studied and to understand the impact on the family during the phases of childhood cancer. The information acquisition was based on documents from the Ministry of Health and on scientific studies available on the following databases: the Google Scholar, the Health virtual Library, the Scielo, the CAPES Journals, the MEDLINE, the LILACS and the Cochrane. The choice of the documents and journals was mainly justified by its link with the childhood health theme. The systematic of the studies research covered the period from 1999 to 2015. The keywords used for the research’s strategy were: childhood health, childhood cancer, family caregivers and grief. The results were presented in three themes: childhood cancer impact on the family, adaptation process of the family facing the sickness and the mourning regarding the death of the sick child. The review enabled to identify the need for special follow-up of the person, which is in direct contact with the child, usually the mother, since the moment of the diagnostic, until after the death.O objetivo desse estudo é revisar a literatura relativa à criança com câncer e sua família, a fim de identificar temas que têm sido pesquisados, e compreender o impacto causado na família durante as fases do câncer infantil. O levantamento de dados foi embasado em documentos do Ministério da Saúde e em trabalhos científicos disponibilizados no Google Acadêmico, Biblioteca virtual da Saúde, Scielo, Periodicos Capes, MEDLINE, LILACS e Cochrane. A escolha dos documentos e periódicos se deu pela sua relação com os temas Saúde da criança. A busca sistematizada de trabalhos abrangeram o período de 1999 a 2015. A estratégia de busca desse referencial utilizou as seguintes palavras-chave: Saúde da Criança, Câncer Infantil, Cuidadores Familiares e Luto. Os resultados foram apresentados em três temas: impacto do câncer infantil na familiar; processo de adaptação da família diante da doença e o luto diante da morte da criança. A revisão demonstrou que uma necessidade de acompanhamento especial a pessoa em contato direto com a criança, geralmente a mãe, desde o momento do diagnostico, e até após a morte
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