A pesquisa foi possível devido ao financiamento do projeto de avaliação de efeitos conservação (CEAP). Somos especialmente gratos para permissão de acesso ao site dos produtores, pesquisa ajuda de membros da unidade de pesquisa do USDA-ARS-Delta água gestão e análise da amostra pelo pessoal do centro de pesquisa de Ecotoxicologia, Universidade do estado de Arkansas. Parte desta pesquisa foi apoiada por uma entrevista para o programa de participação de ARS, administrado pelo Instituto de Oak Ridge para ciência e educação (ORISE) através de um acordo interinstitucional entre o departamento de energia dos EUA e do USDA. ORISE é gerido pela ORAU sob o número de contrato do DOE DE-AC05-06OR23100. Todas as opiniões expressadas neste artigo são do autor e não refletem necessariamente as políticas e pontos de vista do USDA, ARS, DOE ou ORAU/ORISE.

<ol>
	<li>Pellerin, B. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emerging+Tools+for+Continuous+Nutrient+Monitoring+Networks:+Sensors+Advancing+Science+and+Water+Resources+Protection.">Emerging Tools for Continuous Nutrient Monitoring Networks: Sensors Advancing Science and Water Resources Protection.</a> J Am Water Resour Assoc. 52 (4), 993-1008 (2016).</li><li>Rozemeijer, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+and+Evaluation+of+a+New+Passive+Sampler+for+Measuring+Average+Solute+Concentrations+in+a+Catchment+Scale+Water+Quality+Monitoring+Study.">Application and Evaluation of a New Passive Sampler for Measuring Average Solute Concentrations in a Catchment Scale Water Quality Monitoring Study.</a> Environ Sci Tech. 44 (4), 1353-1359 (2010).</li><li>Cassidy, R., Jordan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Limitations+of+instantaneous+water+quality+sampling+in+surface-water+catchments:+Comparison+with+near-continuous+phosphorus+time-series+data.">Limitations of instantaneous water quality sampling in surface-water catchments: Comparison with near-continuous phosphorus time-series data.</a> J. Hydrol. 405 (1-2), 182-193 (2011).</li><li>Facchi, A., Gandolfi, C., Whelan, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparison+of+river+water+quality+sampling+methodologies+under+highly+variable+load+conditions.">A comparison of river water quality sampling methodologies under highly variable load conditions.</a> Chemosphere. 66 (4), 746-756 (2007).</li><li>Hamilton, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Global hydrological monitoring industry trends. , (2012).</li><li>Aryal, N., Reba, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transport+and+transformation+of+nutrients+and+sediment+in+two+agricultural+watersheds+in+Northeast+Arkansas.">Transport and transformation of nutrients and sediment in two agricultural watersheds in Northeast Arkansas.</a> Agric Ecosyst Environ. 236, 30-42 (2017).</li><li>National Research Council (U.S.). <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Confronting the nation's water problems: The role of research. , (2004).</li><li>LMRRA (Lower Mississippi River Resource Assessment). <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Final Assessment in Response to Section 402 of WRDA 2000 Public Review Draft. , (2015).</li><li>MWNTF (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force). <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> New Goal Framework. , (2008).</li><li>Reba, M. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> , (2006).</li><li>World Metorological Organization. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Manual on Stream Gauging Volume I-Fieldwork. , (2010).</li><li>American Public Health Association, American Water Works Association, &amp; Water Environment Federation. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Standard methods for the examination of water &amp; wastewater. , (2005).</li><li>ASTM (American Society of Testing and Materials) D3977-97. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Standard test methods for determining sediment concentration in water samples. , (1997).</li><li>O'Connor, D. 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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nitrogen+losses+in+runoff+from+three+adjacent+agricultural+watersheds+with+claypan+soils.">Nitrogen losses in runoff from three adjacent agricultural watersheds with claypan soils.</a> Agric Ecosyst Environ. 117 (1), 39-48 (2006).</li></ol>

Os autores não têm nada para divulgar.

No geral, o monitoramento contínuo de nutrientes e sedimentos tem várias vantagens sobre monitoramento usando o método de amostragem de garra. Processos de qualidade hidrológico e a água são afetados pela precipitação sobre um espaço muito curto de tempo. Os usuários podem obter dados de alta resolução temporal em nutrientes e sedimentos para estudar problemas complexos. Outros parâmetros de qualidade de água, tais como condutividade, pH, temperatura e fazer, podem ser obtidos simultaneamente e com o mesmo ...

Monitoramento de qualidade de água fornece informações sobre as concentrações de poluentes em diferentes escalas espaciais, dependendo do tamanho da área contribuinte, que pode variar de um lote ou um campo a um divisor de águas. Esse monitoramento ocorre sobre um período de tempo, como um evento único, um dia, uma temporada ou um ano. As informações recolhidas dos monitoramento da qualidade da água, principalmente relacionados com nutrientes (por exemplo, nitrogênio e fósforo) e de sedimentos, podem ser usadas para: 1) compreender os processos hidrológicos e o transporte e transformação de poluentes em riachos, como valas de drenagem agrícola; 2) avaliar a eficiência das práticas de gestão aplicadas para o divisor de águas para reduzir a carga de nutrientes e sedimentos e aumentar a qualidade da água; 3) avaliar a entrega dos sedimentos e nutrientes para a água a jusante; e 4) melhorar a modelagem de nutrientes e sedimentos para compreender o hidrológico e processos de qualidade que determinam o transporte de poluentes e dinâmica na gama de escalas temporais e espaciais de água.
Esta informação é crucial para a restauração do ecossistema aquático, planejamento sustentável e a gestão dos recursos de água1.
O método mais usado para nutriente e monitoramento de sedimentos em uma bacia hidrográfica é a amostragem de garra. Amostragem de garra com precisão representa uma concentração de instantâneo no momento da amostragem2. Isso também pode retratar uma variação das concentrações de poluentes, com o tempo se amostragem frequente é feita. No entanto, amostragem frequente é tempo intensivo e caro, muitas vezes tornando-se impraticável2. Além disso, a amostragem de garra pode sob- ou superestimar as concentrações de poluentes reais fora o tempo de amostragem2,3,4. Por conseguinte, calculadas usando tais concentrações de cargas podem não ser precisas.
Alternativamente, monitoramento contínuo fornece informações precisas e oportunas sobre a qualidade da água em um intervalo de tempo pré-determinado, como um minuto, uma hora ou um dia. Os usuários podem selecionar os intervalos de tempo adequados, com base em suas necessidades. Monitoramento contínuo permite que os pesquisadores, planejadores e gestores otimizar a coleta de amostra; desenvolver e monitorar métricas tempo integradas, tais como cargas diárias máximos totais (TMDLs); avaliar o uso recreativo de massas de água; avaliar as condições de fluxo da linha de base; e espacial e temporalmente avaliar a variação de poluentes para determinar relações de causa-efeito e desenvolver um plano de gerenciamento5,6. Monitoramento contínuo de nutrientes e sedimentos recentemente recebeu maior atenção devido aos avanços na tecnologia de computação e o sensor, a capacidade melhorada de dispositivos de armazenamento e os requisitos de dados crescente preciso estudar processos mais complexos 1 , 5 , 7. em uma pesquisa global com mais de 700 profissionais de água, a utilização de sondas multiparâmetros aumentou de 26% para 61% entre 2002 e 2012 e deve chegar a 66% por 20225. Na mesma pesquisa, 72% dos entrevistados indicaram a necessidade de expansão da sua rede de monitoramento para conhecer seus dados precisa de5. O número de estações em uma rede de monitoramento e o número de variáveis monitoradas por estação em 2012 deverão aumentar em 53% e 64%, respectivamente, até 20225.
No entanto, a qualidade contínua de água e quantidade de monitoramento em bacias hidrográficas agrícolas é um desafio. Eventos de grande chuva lavagem o sedimento e macrófitas, contribuindo para o acúmulo de sedimentos de alta carga e detritos nos sensores e sondas. O escoamento de excesso nitrogênio e fósforo aplicado aos campos agrícolas cria condições ideais para o crescimento dos organismos microscópicos e macroscópicos e a incrustação de instream sensores e sondas, especialmente durante o verão. Incrustação e sedimento pode causar sensores falhar, flutuando, e produzir dados confiáveis. Apesar destes desafios, melhores dados de resolução temporal (tão baixo como por minuto) são necessários para estudar os processos de escoamento superficial e contaminação de fontes não-pontuais, como eles são afetados pelas características da bacia hidrográfica (por exemplo, tamanho, solo, inclinação, etc. ) e o tempo e na intensidade de precipitação7. Observações de campo cuidado, calibração frequente e adequada limpeza e manutenção podem garantir boa qualidade dados de sensores e sondas, mesmo com o tempo de resolução mais fina.
Aqui, vamos discutir um método para o em situ contínuo monitoramento de duas bacias hidrográficas agrícolas utilizando sondas de qualidade de água multiparâmetro, área-velocidade e sensores de transdutor de pressão e Rotating; sua calibração e manutenção de campo; e processamento de dados. O protocolo demonstra uma maneira em que monitoramento de qualidade de água contínua pode ser realizada. O protocolo é geralmente aplicável a água contínua qualidade e a quantidade de monitoramento em qualquer tipo ou tamanho da bacia hidrográfica.
O protocolo foi realizado no nordeste Arkansas em pequenas valas das bacias hidrográficas (HUC 080202040803, 53,4 km2 de área) e Lower St. Francis Basin (HUC 080202030801, área de 23,4 km2 ). Estas duas bacias desaguam afluentes do rio Mississippi. A necessidade de monitoramento de afluentes do rio Mississippi foi identificada pelo Comité de conservação inferior do rio Mississippi e o Golfo de México hipóxia força-tarefa para desenvolver um plano de gestão de bacia hidrográfica e anotar o progresso das atividades de manejo 8 , 9. Além disso, essas bacias são caracterizadas como foco as bacias hidrográficas pelos Estados Unidos Departamento de Agricultura-Natural Resources Conservation Service (USDA-CRN), baseadas no potencial para reduzir a poluição de nutrientes e sedimento e para melhoria de qualidade de água10. Borda de campo monitoramento está sendo realizado nestas bacias hidrográficas como parte da rede estadual rio Mississippi bacia hidrográfica saudável iniciativa (MRBI)11. Mais detalhes de bacias hidrográficas (ou seja, locais, características da bacia hidrográfica, etc.) são fornecidas em edu e Reba (2017)6. Em suma, pouco falta à bacia do rio tem predominantemente solos de barro de lodo, e algodão e soja são as principais culturas, Considerando que o Lower St. Francis Basin tem predominantemente Sharkey argila do solo, e arroz e feijão de soja são as principais culturas. Em cada bacia hidrográfica, em situ água contínua quantidade e qualidade (ou seja, a temperatura de descarga, pH, DO, turbidez, condutividade, nitrato e amônio) de monitoramento foi realizado em três estações no mainstream usando esse protocolo para entenda a variabilidade espacial e temporal das cargas poluentes e os processos hidrológicos. Além disso, semanalmente amostras de água foram coletadas e analisadas para sedimentos suspensos concentration.

<table border="0" cellpadding="0" cellspacing="0" width="812">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">Multiparameter sonde</td>
			<td style="width:109px;">Hach Hydrolab</td>
			<td style="width:135px;">DS5X</td>
			<td style="width:419px;">measures temperature, pH, conductivity, dissolved oxygen, nitrate, ammonium, turbidity</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:149px;">Area velocity flow module and sensor</td>
			<td style="width:109px;">Teledyne Isco</td>
			<td style="width:135px;">2150</td>
			<td style="width:419px;">measures average stream velocity and flow depth, and calculates flow rate and total flow based on provided cross-section area of the ditch. Stored data can be downloaded directly to computer.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">Automatic portable water sampler</td>
			<td style="width:109px;">Teledyne Isco</td>
			<td style="width:135px;">ISCO 6712</td>
			<td style="width:419px;">automatically samples water in the set interval or in conjunction with flow module and sensor</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">Pressure Transducer</td>
			<td style="width:109px;">In-situ</td>
			<td style="width:135px;">Rugged Troll 100</td>
			<td style="width:419px;">measures presure, level and temperature in the water. Stored data can be directly downloaded to the computer</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">Portable flow meter</td>
			<td style="width:109px;">Flo-mate (Hach)</td>
			<td style="width:135px;">Marsh-McBirney 2000</td>
			<td style="width:419px;">For manual discharge measurement</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">Battery, 12 v, rechargeable</td>
			<td style="width:109px;">UPG</td>
			<td style="width:135px;">UB 1270</td>
			<td style="width:419px;">To power sonde</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">Battery, 12 v, rechargeable</td>
			<td style="width:109px;">Interstate Batteries</td>
			<td style="width:135px;">SRM 27</td>
			<td style="width:419px;">Lead acid battery to power autosampler</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Solar panel</td>
			<td style="width:109px;">Alt E</td>
			<td style="width:135px;">ALT20-12P</td>
			<td style="width:419px;">To recharge battery at the site</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">C-8 batteries</td>
			<td style="width:109px;"></td>
			<td style="width:135px;"></td>
			<td style="width:419px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">Calibration standards</td>
			<td style="width:109px;">Hach or Fisher Scientific</td>
			<td style="width:135px;">mulitple</td>
			<td style="width:419px;">Standards of pH (4,7,10), conductivity (1412 uS/cm), nitrate (5 and 50 mg/L), ammonium (5 and 50 mg/L), and turbidity (50,100,200 NTU)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">High nitrate standard</td>
			<td style="width:109px;">Hach</td>
			<td style="width:135px;">013810HY</td>
			<td style="width:419px;">50 mg/L</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Low nitrate standard</td>
			<td style="width:109px;">Hach</td>
			<td style="width:135px;">013800HY</td>
			<td style="width:419px;">5 mg/L</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">High ammonium standard</td>
			<td style="width:109px;">Hach</td>
			<td style="width:135px;">002588HY</td>
			<td style="width:419px;">50 mg/L</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Low ammonium standard</td>
			<td style="width:109px;">Hach</td>
			<td style="width:135px;">002587HY</td>
			<td style="width:419px;">5 mg/L</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Turbidity standard</td>
			<td style="width:109px;">Fisher scientific</td>
			<td>R8819050-500G</td>
			<td style="width:419px;">50 NTU</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Turbidity standard</td>
			<td style="width:109px;">Fisher scientific</td>
			<td>88-061-6</td>
			<td style="width:419px;">100 NTU</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Turbidity standard</td>
			<td style="width:109px;">Fisher scientific</td>
			<td>R8819200500 C</td>
			<td style="width:419px;">200 NTU</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Potassium chloride salt pellets</td>
			<td style="width:109px;">Hach</td>
			<td style="width:135px;">005376HY</td>
			<td style="width:419px;">to maintain electrolyte for pH electrode</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Potassium chloride standard</td>
			<td style="width:109px;">Fisher scientific</td>
			<td style="width:135px;">5890-16</td>
			<td style="width:419px;">1412 us/cm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Buffer solution, pH 4</td>
			<td style="width:109px;">Fisher scientific</td>
			<td style="width:135px;">SB99-1</td>
			<td style="width:419px;">for pH sensor calibration</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Buffer solution, pH 7</td>
			<td style="width:109px;">Fisher scientific</td>
			<td style="width:135px;">SB108-1</td>
			<td style="width:419px;">for pH sensor calibration</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Buffer solution, pH 10</td>
			<td style="width:109px;">Fisher scientific</td>
			<td style="width:135px;">SB116-1</td>
			<td style="width:419px;">for pH sensor calibration</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Silicon sealant</td>
			<td style="width:109px;">Hach</td>
			<td style="width:135px;">00298HY</td>
			<td style="width:419px;">For sealing sensor battery cover water tight</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">All purpose cleaner</td>
			<td style="width:109px;">Sunshine Makers Inc</td>
			<td style="width:135px;">Simple green</td>
			<td style="width:419px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Wipes</td>
			<td style="width:109px;">Kimberly-Clark</td>
			<td style="width:135px;"></td>
			<td style="width:419px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">L-bracket</td>
			<td style="width:109px;"></td>
			<td style="width:135px;"></td>
			<td style="width:419px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:149px;">Telsbar post</td>
			<td style="width:109px;">Unistrut Service Company</td>
			<td style="width:135px;"></td>
			<td style="width:419px;">Secure sensors and sondes in the stream</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Steel wire</td>
			<td style="width:109px;"></td>
			<td style="width:135px;"></td>
			<td style="width:419px;">supend sonde and PT sensor</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Carabiner</td>
			<td style="width:109px;"></td>
			<td style="width:135px;"></td>
			<td style="width:419px;">supend sonde and PT sensor</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Allen wrench</td>
			<td style="width:109px;"></td>
			<td style="width:135px;"></td>
			<td style="width:419px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:149px;">Copper wire mesh</td>
			<td style="width:109px;">Bird B Gone</td>
			<td style="width:135px;"></td>
			<td style="width:419px;">Rodent and bird control copper mesh roll</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">Adhesive Tape</td>
			<td style="width:109px;">Agri Drain Corporation</td>
			<td style="width:135px;"></td>
			<td style="width:419px;">Tile tape, works in wet and cold weather</td>
		</tr>
	</tbody>
</table>

continuous instream monitoring of nutrients and sediment in agricultural watersheds

As concentrações de poluentes e cargas em bacias hidrográficas variam consideravelmente com o tempo e espaço. Informações precisas e oportunas sobre a magnitude dos poluentes nos recursos hídricos são um pré-requisito para a compreensão os drivers das cargas poluentes e para tomar decisões informada água recurso de gerenciamento. O método comumente usado "agarra a amostragem" fornece as concentrações de poluentes no momento da amostragem (ou seja, uma concentração de instantâneo) e pode sob- ou overpredict as concentrações de poluentes e cargas. Monitoramento contínuo de nutrientes e sedimentos recentemente tem recebido mais atenção devido aos avanços em computação, tecnologia e dispositivos de armazenamento de detecção. Este protocolo demonstra o uso de sensores, sondas e instrumentação para monitorar continuamente em situ nitrato de amónio, turbidez, pH, condutividade, temperatura e oxigênio dissolvido (DO) e calcular as cargas dos dois córregos (valas) em duas bacias hidrográficas agrícolas. Com a calibração adequada, manutenção e operação de sensores e sondas, dados de qualidade de água boa podem ser obtidos por superar condições desafiadoras como acúmulo de sujidade e detritos. O método também pode ser usado em bacias de vários tamanhos e caracterizado por terrenos agrícolas, florestais e/ou urbano.

Na publicação (2017) edu e Reba, este protocolo foi usado para estudar o transporte e a transformação de nutrientes e sedimentos em duas bacias hidrográficas agrícolas pequeno6. Resultados adicionais do presente protocolo são descritos abaixo.
Precipitação-escoamento relacionamentos de qualidade de água:
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Monitoramento Contínuo de Nutrientes e Sedimentos em Bacias Hidrográficas Agrícolas | Meio Ambiente | Vídeo

Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds

Com o avanço da tecnologia e o aumento nas expectativas do usuário final, aumentou a necessidade e o uso de maior resolução temporal de dados para estimativa de carga poluente. Este protocolo descreve um método para contínua em situ água qualidade acompanhamento para obter dados de resolução temporal maiores para água informado as decisões de gestão de recursos.

Monitoramento Contínuo de Nutrientes e Sedimentos em Bacias Agrícolas

Pollutant concentrations and loads in watersheds vary considerably with time and space. Accurate and timely information on the magnitude of pollutants in ...

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11.1K visualizações.  Oak Ridge Institute of Science and Education (ORISE). Com o avanço da tecnologia e o aumento nas expectativas do usuário final, aumentou a necessidade e o uso de maior resolução temporal de dados para estimativa de carga poluente. Este protocolo descreve um método para contínua em situ água qualidade acompanhamento para obter dados de resolução temporal maiores para água informado as decisões de gestão de recursos.

Vídeo: Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds

Measuring Fluxes of Mineral Nutrients and Toxicants in Plants with Radioactive Tracers

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. Radioisotope tracing is a major technique used to measure such fluxes, both within plants, and between plants and their environments. Flux data obtained with radiotracer protocols can help elucidate the capacity, mechanism, regulation, and energetics of transport systems for specific mineral nutrients or toxicants, and can provide insight into compartmentation and turnover rates of subcellular mineral and metabolite pools. Here, we describe two major radioisotope protocols used in plant biology: direct influx (DI) and compartmental analysis by tracer efflux (CATE). We focus on flux measurement of potassium (K+) as a nutrient, and ammonia/ammonium (NH3/NH4+) as a toxicant, in intact seedlings of the model species barley (Hordeum vulgare L.). These protocols can be readily adapted to other experimental systems (e.g., different species, excised plant material, and other nutrients/toxicants). Advantages and limitations of these protocols are discussed.

In planta measurement of nutrient and toxicant fluxes is essential to the study of plant nutrition and toxicity. Here, we cover radiotracer protocols for influx and efflux determination in intact plant roots, using potassium (K+) and ammonia/ammonium (NH3/NH4+) fluxes as examples. Advantages and limitations of such techniques are discussed.

Medindo Fluxos de nutrientes minerais e substâncias tóxicas em plantas com Traçadores Radioativos

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. ...

Ambiente

Sediment Core Sectioning and Extraction of Pore Waters under Anoxic Conditions

We demonstrate a method for sectioning sediment cores and extracting pore waters while maintaining oxygen-free conditions. A simple, inexpensive system is built and can be transported to a temporary work space close to field sampling site(s) to facilitate rapid analysis. Cores are extruded into a portable glove bag, where they are sectioned and each 1-3 cm thick section (depending on core diameter) is sealed into 50 ml centrifuge tubes. Pore waters are separated with centrifugation outside of the glove bag and then returned to the glove bag for separation from the sediment. These extracted pore water samples can be analyzed immediately. Immediate analyses of redox sensitive species, such as sulfide, iron speciation, and arsenic speciation indicate that oxidation of pore waters is minimal; some samples show approximately 100% of the reduced species, e.g. 100% Fe(II) with no detectable Fe(III). Both sediment and pore water samples can be preserved to maintain chemical species for further analysis upon return to the laboratory.

A protocol for sectioning sediment cores and extracting pore waters under anoxic conditions in order to permit analysis of redox sensitive species in both solids and fluids is presented.

Sedimentos Núcleo de corte e extração de Pore Waters sob condições anóxicas

We demonstrate a method for sectioning sediment cores and extracting pore waters while maintaining oxygen-free conditions. A simple, inexpensive system is ...

Characterization and Application of Passive Samplers for Monitoring of Pesticides in Water

Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study provides a protocol for the passive sampler preparation, calibration, extraction method and instrumental analysis. Sampling rates (RS) and passive sampler-water partition coefficients (KPW) were calculated for silicone rubber, polar organic chemical integrative sampler POCIS-A, POCIS-B, SDB-RPS and C18 disk. The uptake of the selected compounds depended on their physicochemical properties, i.e., silicone rubber showed a better uptake for more hydrophobic compounds (log octanol-water partition coefficient (KOW) &#62; 5.3), whereas POCIS-A, POCIS-B and SDB-RPS disk were more suitable for hydrophilic compounds (log KOW &#60; 0.70).

A protocol about the characterization and application of five different passive sampling devices is presented.

Caracterização e aplicação de amostradores passivos de monitorização de pesticidas em água

Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study ...

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in nutrient and gas cycles. After cores with intact sediment-water interfaces are collected, they are submerged in incubation tanks and kept under aerobic conditions at in situ temperatures. To initiate a time course of overlying water chemistry, cores are sealed without bubbles using a top cap with a suspended stirrer. Time courses of 4-7 sample points are used to determine the rate of sediment water exchange. Artificial illumination simulates day-time conditions for shallow photosynthetic sediments, and in conjunction with dark incubations can provide net exchanges on a daily basis. The net measurement of N2 is made possible by sampling a time course of dissolved gas concentrations, with high precision mass spectrometric analysis of N2:Ar ratios providing a means to measure N2 concentrations. We have successfully applied this approach to lakes, reservoirs, estuaries, wetlands and storm water ponds, and with care, this approach provides valuable information on biogeochemical balances in aquatic ecosystems.

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations

Here, we present small core incubations for the measurement of sediment-water gas and solute exchange. These will provide reliable measurements of sediment-water exchange that assess the role of sediment in influencing biological and biogeochemical processes in aquatic ecosystems.

A Bolsa Benthic de O<sub&gt; 2</sub&gt;, N<sub&gt; 2</sub&gt; e nutrientes dissolvidos Usando pequeno núcleo incubações

The measurement of sediment-water exchange of gases and solutes in aquatic sediments provides data valuable for understanding the role of sediments in ...

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonate (CaCO3) profiles. The objective is to describe a simple conceptual model and detailed protocol for repeatable field and laboratory measurements of these quantities. Here, accurate elevation is measured using a ground-based differential global positioning system (GPS); other data acquisition methods could be applied to the same basic method. Soil samples are collected from prescribed depth intervals and analyzed in the lab using an efficient and precise modified pressure-calcimeter method for quantitative analysis of inorganic carbon concentration. Standard statistical methods are applied to point data, and representative results show significant correlations between changes in soil surface layer CaCO3 and changes in elevation consistent with the conceptual model; CaCO3 generally decreased in depositional areas and increased in erosional areas. Maps are derived from point measurements of elevation and soil CaCO3 to aid analyses. A map of erosional and depositional patterns at the study site, a rain-fed winter wheat field cropped in alternating wheat-fallow strips, shows the interacting effects of water and wind erosion affected by management and topography. Alternative sampling methods and depth intervals are discussed and recommended for future work relating soil erosion and deposition to soil CaCO3.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonates. Repeatable methods for field and laboratory measurements of these quantities and data analysis methods are described here.

Medição e mapeamento de padrões de erosão e deposição relacionadas às concentrações de carbonato de solo sob gestão agrícola

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes ...

Continuous Hydrologic and Water Quality Monitoring of Vernal Ponds

Vernal ponds, also referred to as vernal pools, provide critical ecosystem services and habitat for a variety of threatened and endangered species. However, they are vulnerable parts of the landscapes that are often poorly understood and understudied. Land use and management practices, as well as climate change are thought to be a contribution to the global amphibian decline. However, more research is needed to understand the extent of these impacts. Here, we present methodology for characterizing a vernal pond's morphology and detail a monitoring station that can be used to collect water quantity and quality data over the duration of a vernal pond's hydroperiod. We provide methodology for how to conduct field surveys to characterize the morphology and develop stage-storage curves for a vernal pond. Additionally, we provide methodology for monitoring the water level, temperature, pH, oxidation-reduction potential, dissolved oxygen, and electrical conductivity of water in a vernal pond, as well as monitoring rainfall data. This information can be used to better quantify the ecosystem services that vernal ponds provide and the impacts of anthropogenic activities on their ability to provide these services.

Understanding the ecosystem services and processes provided by vernal ponds and the impacts of anthropogenic activities on their ability to provide these services requires intensive hydrologic monitoring. This sampling protocol using in-situ monitoring equipment was developed to understand the impact of anthropogenic activities on water levels and quality.

Contínua hidrológicos e monitoramento da qualidade do Vernal lagoas de água

Vernal ponds, also referred to as vernal pools, provide critical ecosystem services and habitat for a variety of threatened and endangered species. ...

The Hawaii Protocol for Scientific Monitoring of Coffee Berry Borer: a Model for Coffee Agroecosystems Worldwide

Coffee berry borer (CBB) is the most devastating insect pest for coffee crops worldwide. We developed a scientific monitoring protocol that is aimed at capturing and quantifying the dynamics and impact of this invasive insect pest as well as the development of its host plant across a heterogeneous landscape. The cornerstone of this comprehensive monitoring system is timely georeferenced data collection on CBB movement, coffee berry infestation, mortality by the fungus Beauveria bassiana, and coffee plant phenology via a mobile electronic data recording application. This electronic data collection system allows field records to be georeferenced through built-in global positioning systems, and is backed by a network of weather stations and records of farm management practices. Comprehensive monitoring of CBB and host plant dynamics is an essential part of an area-wide project in Hawaii to aggregate landscape-level data for research to improve management practices. Coffee agroecosystems in other parts of the world that experience highly variable environmental and socioeconomic factors will also benefit from implementing this protocol, in that it will drive the development of customized integrated pest management (IPM) to manage CBB populations.

Comprehensive monitoring of coffee berry borer and host plant dynamics is essential for aggregating landscape-level data to improve management of this invasive pest. Here, we present a protocol for scientific monitoring of coffee berry borer movement, infestation, mortality, coffee plant phenology, weather, and farm management via a mobile electronic data recording application.

O protocolo de Havaí para acompanhamento científico da broca do café: um modelo para agroecossistemas de café no mundo

Coffee berry borer (CBB) is the most devastating insect pest for coffee crops worldwide. We developed a scientific monitoring protocol that is aimed at ...

The Plant Infection Test: Spray and Wound-Mediated Inoculation with the Plant Pathogen Magnaporthe Grisea

Plants possess a powerful system to defend themselves against potential threats by pathogenic fungi. For agriculturally important plants, however, current measures to combat such pathogens have proved too conservative and, thus, not sufficiently effective, and they can potentially pose environmental risks. Therefore, it is extremely necessary to identify host-resistance factors to assist in controlling plant diseases naturally through the identification of resistant germplasm, the isolation and characterization of resistance genes, and the molecular breeding of resistant cultivars. In this regard, there is need to establish an accurate, rapid, and large-scale inoculation method to breed and develop plant resistance genes. The rice blast fungal pathogen Magnaporthe grisea causes severe disease symptoms and yield losses. Recently, M. grisea has emerged as a model organism for studying the mechanisms of plant-fungal pathogen interactions. Hence, we report the development of a plant virulence test method that is specific for M. grisea. This method provides for both spray inoculation with a conidial suspension and wounding inoculation with mycelium cubes or droplets of conidial suspension. The key step of the wounding inoculation method for detached rice leaves is to make wounds on plant leaves, which avoids any interference caused by host penetration resistance. This spray/wounding protocol contributes to the rapid, accurate, and large-scale screening of the pathotypes of M. grisea isolates. This integrated and systematic plant infection method will serve as an excellent starting point for gaining a broad perspective of issues in plant pathology.

The Plant Infection Test: Spray and Wound-Mediated Inoculation with the Plant Pathogen Magnaporthe Grisea

Here, we present a protocol to test plant virulence with the plant pathogen Magnaporthe grisea. This report will contribute to the large-scale screening of the pathotypes of fungi isolates and serve as an excellent starting point for understanding the resistant mechanisms of plants during molecular breeding.

O teste de infecção da planta: Spray e inoculação mediada por ferimento com o de patógeno vegetal Magnaporthe Grisea

Plants possess a powerful system to defend themselves against potential threats by pathogenic fungi. For agriculturally important plants, however, current ...

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors

Denitrification is the primary biogeochemical process removing reactive nitrogen from the biosphere. The quantitative evaluation of this process has become particularly relevant for assessing the anthropogenic-altered global nitrogen cycle and the emission of greenhouse gases (i.e., N2O). Several methods are available for measuring denitrification, but none of them are completely satisfactory. Problems with existing methods include their insufficient sensitivity, and the need to modify the substrate levels or alter the physical configuration of the process using disturbed samples.This work describes a method for estimating sediment denitrification rates that combines coring, acetylene inhibition, and microsensor measurements of the accumulated N2O. The main advantages of this method are a low disturbance of the sediment structure and the collection of a continuous record of N2O accumulation; these enable estimates of reliable denitrification rates with minimum values up to 0.4-1 &#181;mol N2O m-2 h-1. The ability to manipulate key factors is an additional advantage for obtaining experimental insights. The protocol describes procedures for collecting the cores, calibrating the sensors, performing the acetylene inhibition, measuring the N2O accumulation, and calculating the denitrification rate. The method is appropriate for estimating denitrification rates in any aquatic system with retrievable sediment cores. If the N2O concentration is above the detection limit of the sensor, the acetylene inhibition step can be omitted to estimate the N2O emission instead of denitrification. We show how to estimate both actual and potential denitrification rates by increasing nitrate availability as well as the temperature dependence of the process. We illustrate the procedure using mountain lake sediments and discuss the advantages and weaknesses of the technique compared to other methods. This method can be modified for particular purposes; for instance, it can be combined with 15N tracers to assess nitrification and denitrification or field in situ measurements of denitrification rates.

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors

This method estimates sediment denitrification rates in sediment cores using the acetylene inhibition technique and microsensor measurements of the accumulated N2O. The protocol describes procedures for collecting the cores, calibrating the sensors, performing the acetylene inhibition, measuring the N2O accumulation, and calculating the denitrification rate.

Estimando taxas de desnitrificação do sedimento usando núcleos e N2O Microssensores

Denitrification is the primary biogeochemical process removing reactive nitrogen from the biosphere. The quantitative evaluation of this process has ...

Two-Dimensional Visualization and Quantification of Labile, Inorganic Plant Nutrients and Contaminants in Soil

We describe a method for two-dimensional (2D) visualization and quantification of the distribution of labile (i.e., reversibly adsorbed) inorganic nutrient (e.g., P, Fe, Mn) and contaminant (e.g., As, Cd, Pb) solute species in the soil adjacent to plant roots (the &#8216;rhizosphere&#8217;) at sub-millimeter (~100 &#181;m) spatial resolution. The method combines sink-based solute sampling by the diffusive gradients in thin films (DGT) technique with spatially resolved chemical analysis by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The DGT technique is based on thin hydrogels with homogeneously distributed analyte-selective binding phases. The variety of available binding phases allows for the preparation of different DGT gel types following simple gel fabrication procedures. For DGT gel deployment in the rhizosphere, plants are grown in flat, transparent growth containers (rhizotrons), which enable minimal invasive access to a soil-grown root system. After a pre-growth period, DGT gels are applied to selected regions of interest for in situ solute sampling in the rhizosphere. Afterwards, DGT gels are retrieved and prepared for subsequent chemical analysis of the bound solutes using LA-ICP-MS line-scan imaging. Application of internal normalization using 13C and external calibration using matrix-matched gel standards further allows for the quantification of the 2D solute fluxes. This method is unique in its capability to generate quantitative, sub-mm scale 2D images of multi-element solute fluxes in soil-plant environments, exceeding the achievable spatial resolution of other methods for measuring solute gradients in the rhizosphere substantially. We present the application and evaluation of the method for imaging multiple cationic and anionic solute species in the rhizosphere of terrestrial plants and highlight the possibility of combining this method with complementary solute imaging techniques.

This protocol presents a workflow for sub-mm 2D visualization of multiple labile inorganic nutrient and contaminant solute species using diffusive gradients in thin films (DGT) combined with mass spectrometry imaging. Solute sampling and high-resolution chemical analysis are described in detail for quantitative mapping of solutes in the rhizosphere of terrestrial plants.

Monitoramento Contínuo de Nutrientes e Sedimentos em Bacias Agrícolas

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