•We evaluated the uncertainty in mass measurements of four electronic configurations in lysimeter.•Uncertainty in excitation and acquisition by datalogger increase the system general ...uncertainty.•Periodic calibrations are necessary to compensate systematic errors due the damage by use.•Only regression analysis is not sufficient to evaluate weighing lysimeters.•Errors and uncertainties were attenuate due the use of indicator module in the Measurement System.
The determination of measurement reliability in weighing lysimeters via error analysis is essential for scientific research and irrigation management. The objective of this study was to evaluate four different weight measuring systems (MSs) applied to load cell weighing lysimeters and compare the results with the expected uncertainty values obtained from data provided by manufacturers. A weighing lysimeter with an area of 0.385 m2 and a volume of 0.289 m3 was used, installed on three load cells. In MS1, the load cells were connected to a junction box and the box to a weighing indicator module in a six-wire configuration. In MS2, a four-wire connection was used between the junction box and a datalogger, whereas in MS3, there was a six-wire connection. For MS4, the connection between the load cells and datalogger was direct. The uncertainties of the measurement systems were determined from the calibration results. MS1 presented the lowest measurement errors and uncertainties, resulting in performance superior to those of the other MSs. After MS1, the best performances were obtained by MS2 and MS3, and MS4 presented the worst performance. The effect of the signal measurement uncertainties and the excitation by the datalogger had the greatest effects on the overall uncertainty of the system compared with the influence of temperature on the load cells. The measurement system may be selected according to the technical data supplied by the manufacturer; however, periodic calibration of the effective measuring range is necessary to verify and compensate for systematic errors, which are accentuated during the operation time.
ABSTRACT The objective of this study was to evaluate the performance of the common bean crop grown with application of osmoprotectants based on algae of the genus Durvillaea potatorum in the winter ...crop season, with occurrence or not of water suppression. The experiment used a randomized block design, in split plots, arranged in a 4x7 factorial scheme, in which the plots were composed of four treatments - periods of water suppression (7, 14, 21 days and the control treatment: 100% of field capacity throughout the crop cycle) and the subplots consisted of seven types of osmoprotectants. The treatments with osmoprotectants was applied during the full flowering of the common bean. Three days after application of osmoprotectants, the treatments with suppression of irrigation were established. The use of osmoprotectants based on algae of the genus Durvillaea does not affect the variables plant height, stem diameter, stem and pod dry matter, first pod height, number of pods per plant and number of grains per pod in common bean plants cultivated with occurrence of water suppression. Common bean plants under water restriction conditions have lower leaf and shoot dry matter and lower 100-grain weight. Common bean grain yield was influenced by the type of osmoprotectants and the water suppression period.
RESUMO Objetivou-se, neste estudo, avaliar o desempenho da cultura do feijão comum cultivado com a aplicação de osmoprotetores à base de extratos de algas marinhas do gênero Durvillaea potatorum na safra de inverno com ocorrência ou não de supressão hídrica. O delineamento utilizado foi em blocos casualizados e em parcelas subdivididas em esquema fatorial 4 x 7, as parcelas foram compostas por quatro tratamentos - períodos de supressão hídrica (7, 14, 21 dias e o controle: 100% da capacidade de campo durante todo o ciclo da cultura); nas subparcelas os tratamentos foram sete tipos de osmoprotetores. A aplicação dos tratamentos com osmoprotetores ocorreu em plena floração do feijoeiro. Três dias após a aplicação foram estabelecidos os tratamentos de supressão de irrigação. O uso de osmoprotetores à base de algas do gênero Durvillaea não afeta as variáveis altura de plantas, diâmetro de caule, massa seca de caule e vagens, altura de inserção da primeira vagem, número de vagens por planta, grãos por vagem em plantas de feijão em cultivo com ocorrência ou não de supressão hídrica. Plantas de feijão estabelecidas em condição de restrição hídrica apresentam menor massa seca de folhas e parte aérea e massa de cem grãos. O rendimento de grãos do feijoeiro foi influenciado pelo tipo de osmoprotetor e pelo período de supressão.
ABSTRACT Despite highly efficient, the main limitation of using drip irrigation for fertigation with nitrogen (N) fertilizers is the sensitivity of emitters to clogging by contaminants. The objective ...in this study was to assess the effect of different sources of N fertilizer and different operation times on water distribution uniformity and emitter clogging using a localized surface drip irrigation system. A randomized block experimental design with three replicates was used, in a 5 × 6 factorial arrangement consisting of five N sources (potassium nitrate, ammonium sulfate, calcium nitrate, ammonium nitrate, and urea) and six operation times (100, 200, 300, 400, 500, and 600 hours). The same nitrogen (N) rate applied in all treatments was equivalent to 100 kg ha-1. The drip tubing used had a nominal flow of 2 L h-1, nominal diameter of 16 mm, internal diameter of 13 mm, operating pressure of 100 to 350 kPa, and spacing between emitters of 0.7 m. The variables evaluated were: statistical uniformity coefficient, absolute uniformity coefficient, and degree of clogging. The best absolute and statistical uniformity coefficients were found when using urea and ammonium nitrate for fertigation, mainly at the longest operation times, which presented the best water application uniformity (>91.72%).
RESUMO Apesar da elevada eficiência, a principal limitação dos sistemas de irrigação localizada para uso em fertirrigação com fertilizantes nitrogenados é a sensibilidade de obstrução dos emissores por contaminantes. O objetivo deste trabalho foi avaliar o efeito de fontes de adubos nitrogenados em diferentes tempos de funcionamentos na uniformidade de distribuição de água e no entupimento de emissores em um sistema de irrigação localizada por gotejamento superficial. O delineamento experimental utilizado foi em blocos ao acaso, no esquema fatorial 5 × 6, com três repetições. Os tratamentos consistiram em cinco fontes de N (nitrato de potássio, sulfato de amônio, nitrato de cálcio, nitrato de amônio e ureia) e seis tempos de funcionamento (100, 200, 300, 400, 500 e 600 h). Foi aplicada uma dose de nitrogênio igual para todos os tratamentos, equivalente a uma recomendação de 100 kg ha-1 de N. Foi utilizado um modelo de tubo gotejador com vazão nominal de 2 L h-1, diâmetro nominal 16 mm, diâmetro interno 13 mm, pressão de operação 100 a 350 kPa e espaçamento entre emissores de 0.7 m. As variáveis avaliadas foram o coeficiente de uniformidade estatístico, coeficiente de uniformidade absoluto e o grau de entupimento. Os melhores coeficiente de uniformidade absoluto e estatístico foram encontrados na fertirrigação com ureia e nitrato de amônio, principalmente nos tempos de funcionamento finais, onde foram verificados os melhores valores de uniformidade de aplicação de água (>91,72%).
Neste trabalho, buscou-se avaliar a suscetibilidade de modelos de tubos gotejadores ao entupimento, quando expostos ao uso de cloreto de potássio (branco e vermelho), aplicados via diferentes ...qualidades de água. O experimento foi realizado no Laboratório de Irrigação do Departamento de Engenharia Rural da Escola Superior de Agricultura "Luiz de Queiroz" ESALQ/USP, por um período de nove meses, analisando o desempenho de oito modelos de tubos gotejadores convencionais, com quatro tratamentos e dez repetições, sendo cada repetição representada por um gotejador. Os tratamentos aplicados foram: (T1-Lg/B) água do lago x cloreto de potássio branco; (T2-Lg/V) água do lago x cloreto de potássio vermelho; (T3-Lb/B) água do laboratório x cloreto de potássio branco, e (T4-Lb/V) água do laboratório x cloreto de potássio vermelho. Os modelos de tubos gotejadores apresentaram desempenhos variáveis, sugerindo que a arquitetura interna dos gotejadores foi o fator determinante na caracterização do processo de entupimento. Não foi observado elevado entupimento com relação à aplicação dos cloretos de potássio branco e vermelho na ausência ou presença de fitoplâncton, mostrando que é possível utilizar cloreto de potássio vermelho em fertirrigação.
This work aimed to evaluate the susceptibility of several dripline models against the clogging process when exposed to potassium chloride (white and red), applied through different water qualities (fertigation). The experiment was accomplished in three phases, at the Laboratory of Irrigation of the Department of Rural Engineering at ESALQ/USP, for a period of nine months, by analyzing the performance of eight conventional drip models, with four treatments and ten repetitions, being each repetition a dripper. The applied treatments were: (T1-Lg/B) water of the lake x chloride of white potassium; (T2-Lg/V) water of the lake x chloride of red potassium; (T3Lb/B) water of the laboratory x chloride of white potassium and (T4-Lb/V) water of the laboratory x chloride of red potassium. The dripline models presented variable performance, suggesting that internal architecture of emitters is a major factor related to clogging resistance for imposed treatments. It was not observed high clogging with the application of white or red potassium chloride, under different water quality conditions, showing that it is possible to use the red potassium chloride for fertigation without problems.
It is presented a software developed with Delphi programming language to compute the reservoir's annual regulated active storage, based on the sequent-peak algorithm. Mathematical models used for ...that purpose generally require extended hydrological series. Usually, the analysis of those series is performed with spreadsheets or graphical representations. Based on that, it was developed a software for calculation of reservoir active capacity. An example calculation is shown by 30-years (from 1977 to 2009) monthly mean flow historical data, from Corrente River, located at São Francisco River Basin, Brazil. As an additional tool, an interface was developed to manage water resources, helping to manipulate data and to point out information that it would be of interest to the user. Moreover, with that interface irrigation districts where water consumption is higher can be analyzed as a function of specific seasonal water demands situations. From a practical application, it is possible to conclude that the program provides the calculation originally proposed. It was designed to keep information organized and retrievable at any time, and to show simulation on seasonal water demands throughout the year, contributing with the elements of study concerning reservoir projects. This program, with its functionality, is an important tool for decision making in the water resources management.
O objetivo deste trabalho é apresentar a criação de um programa computacional desenvolvido em linguagem de programação Delphi, para calcular o volume útil de armazenamento de reservatórios com regularização anual, com base no algoritmo dos picos sequenciais. Os modelos matemáticos utilizados para tal finalidade, geralmente, requerem séries hidrológicas extensas, cuja análise poderá ser facilitada através da criação de planilhas ou gráficos que possam representá-las. Neste sentido, foi desenvolvido um programa computacional para o cálculo do volume útil de armazenamento de reservatórios, utilizando-se, como exemplo, de uma série histórica com 30 anos (desde 1977 até 2009) de valores médios mensais de vazão do Rio Corrente, localizado na Bacia Hidrográfica do Rio São Francisco, Brasil. A interface computacional elaborada, como ferramenta adicional para a gestão de recursos hídricos, proporciona flexibilidade na manipulação dos dados e agilidade na interpretação das informações de interesse. Além disso, demandas sazonais de água podem ser analisadas em função de situações específicas, como planejamentos estratégicos de regiões que apresentam grandes consumos de água para a prática da irrigação. Conclui-se, a partir de um exemplo prático, que o programa computacional fornece o cálculo proposto inicialmente, tendo sido projetado para manter as informações organizadas e recuperáveis, a qualquer momento. O programa realiza simulações de demandas sazonais de água ao longo do ano, contribuindo com os elementos de estudo sobre projetos de reservatórios, o que o torna uma importante ferramenta para tomada de decisão na gestão de recursos hídricos, em razão de suas funcionalidades.
The objective of this study was to evaluate the effect of plant spacing and water supplementation on growth and productivity of physic nut (Jatropha). This research was carried out at the ...experimental area of the Instituto Federal Goiano--Rio Verde during the period 12/09/2009 to 30/04/2011, in a randomized block design with three replications. The factors consisted of seven plant spacings and two water conditions, each plot consisted of 16 plants, and four central plants were considered for data collection. At 60 days after transplanting of seedlings, fortnightly the evaluation of the parameters plant height, number of branches, leaf area and productivity was carried out. The plant spacing showed no significant difference for height, branching and productivity, while the water supplementation had significant effect on height at 240 days after transplanting. Seed production under rainfed conditions was higher in 3 x 3 m spacing and with complementary water in 4 x 4 m spacing. Key words: Jatropha curcas L., biodiesel, rapeseed, emitter Objetivou-se, com este trabalho, avaliar o efeito do espacamento e da complementacao hidrica no crescimento e produtividade do pinhao-manso. O experimento foi conduzido na area experimental do Instituto Federal Goiano, campus Rio Verde, GO, no periodo de 12/09/2009 a 30/04/2011, no delineamento de blocos casualizados com tres repeticoes, os fatores foram sete espacamentos e duas condicoes hidricas, cada parcela constituida de 16 plantas, sendo as quatro plantas centrais a area util. Aos 60 dias apos o transplantio das mudas foram feitas, bimensalmente, as avaliacoes dos parametros altura de planta, numero de ramificacoes, area foliar e produtividade. O fator espacamento nao apresentou diferenca significativa para os parametros altura, ramificacao e produtividade e a complementacao hidrica teve efeito significativo para altura aos 240 dias apos transplantio. A producao de sementes em sequeiro foi maior no espacamento 3 x 3 e com complementacao hidrica no espacamento 4 x 4. Palavras-chave: Jatropha curcas L., biodiesel, oleaginosa, emissor
The objective of this study was to evaluate the effect of plant spacing and water supplementation on growth and productivity of physic nut (Jatropha). This research was carried out at the ...experimental area of the Instituto Federal Goiano--Rio Verde during the period 12/09/2009 to 30/04/2011, in a randomized block design with three replications. The factors consisted of seven plant spacings and two water conditions, each plot consisted of 16 plants, and four central plants were considered for data collection. At 60 days after transplanting of seedlings, fortnightly the evaluation of the parameters plant height, number of branches, leaf area and productivity was carried out. The plant spacing showed no significant difference for height, branching and productivity, while the water supplementation had significant effect on height at 240 days after transplanting. Seed production under rainfed conditions was higher in 3 x 3 m spacing and with complementary water in 4 x 4 m spacing.
Water is limiting for growth and essential for photosynthesis. Crop yield depends on the available amount of this resource and on the efficiency of its use by the plant. This study aimed to evaluate ...the vegetative growth and the gross yield of sugar and ethanol from sugarcane along cane-plant and ratoon cane cultivation, under different irrigation depths for water replenishment, with and without nitrogen (N) application by subsurface drip irrigation. The experimental design was randomized blocks, analyzed in a split-plot scheme, with four replicates, in which the plots were represented by the interaction: irrigation depths (0, 25, 50, 75 and 100% water replenishment of the field capacity), with and without N fertigation, and subplots were represented by 9 evaluation periods (90, 120, 150, 180, 210, 240, 270, 300 and 330 days after planting/days after the first cutting for ratoon cane). The gross yields of sugar and alcohol for water replenishments below 93 and 97%, respectively, are higher in sugarcane of first year than in sugarcane of second year. Fertigation provided greater vegetative growth of ratoon cane. Key words: Saccharum officinarum L. water replenishment yield A agua e limitante para o crescimento e fundamental para a fotossintese; a produtividade das plantas depende da quantidade disponivel deste recurso e da eficiencia de seu uso pelo vegetal. Com esse estudo objetivou-se avaliar o crescimento vegetativo e o rendimento bruto de acucar e alcool da cana-de-acucar ao longo do cultivo da cana-planta e cana-soca, em diferentes laminas de reposicao hidrica, com e sem aplicacao de nitrogenio pelo sistema de irrigacao por gotejamento subsuperficial. O delineamento experimental utilizado foi o de blocos ao acaso analisado em esquema de parcelas subdivididas, com quatro repeticoes, sendo a parcela representada pela interacao das laminas de irrigacao (0, 25, 50, 75 e 100% de reposicao hidrica, da capacidade de campo) com e sem fertirrigacao nitrogenada e as subparcelas por nove epocas de avaliacoes (90, 120, 150, 180, 210, 240, 270, 300 e 330 dias depois do plantio/dias apos o primeiro corte para a cana-soca). Os rendimentos brutos de acucar e alcool para as reposicoes hidricas inferiores a 93 e 97% sao, respectivamente, maiores em cana-planta que em cana-soca. A fertirrigacao proporcionou maior crescimento vegetativo da cana-soca. Palavras-chave: Saccharum officinarum L. reposicao hidrica produtividade
The objective of this research was to evaluate the production of sunflower in the off-season, supplemented or not with irrigation and cultivated after the crops of soybeans, corn or palisade grass. ...The treatments were allocated in a randomized blocks design in split plot (2x3), the supplemental irrigation by center pivot and without irrigation in the plots, and in the subplots the crops predecessors: soybeans, corn and palisade grass, with four replications. The height, stem diameter, shoot dry weight, number of leaves per plant and leaf area were evaluated at 15, 30, 45, 60, 75 and 90 days after emergence of sunflower plants. Sunflower plants were tall under all cultivation conditions, without variability in the evolution of stem diameter and of number of leaves. Leaf area was less in sunflower plants grown under corn straw and palisade grass under non-irrigated conditions. No significant effects on yield components--mass of thousand seeds, head diameter and oil and grain yield were observed. After cultivation of soybean, sunflower plants produced greater dry mass of shoots and higher oil content in the seed compared to plants established under corn stalk.
Objetivou-se, nesta pesquisa, avaliar a produção do girassol na safrinha, suplementado ou não, com irrigação após os cultivos de soja, milho ou capim-marandu. Testaram-se, em blocos casualizados e em ...parcelas subdivididas (2 x 3), a irrigação suplementar por pivô central e a condição de sequeiro nas parcelas e nas subparcelas o cultivo das culturas antecessoras soja, milho e capim-marandu, com quatro repetições. A altura, o diâmetro da haste, a massa seca da parte aérea, o número de folhas por planta e a área foliar foram avaliados aos 15, 30, 45, 60, 75 e 90 dias após a emergência das plantas de girassol. Plantas de girassol apresentaram porte elevado em todas as condições de cultivo sem variabilidade na evolução do diâmetro da haste e do número de folhas. Menor área foliar foi observada em plantas de girassol cultivadas em palha de milho e de capim em condições não irrigadas. Não foram observados efeitos significativos sobre os componentes de rendimento: massa de mil sementes, diâmetro do capítulo e rendimentos de óleo e de grãos. Após o cultivo da soja as plantas de girassol produziram maior massa seca da parte aérea e maior teor de óleo nas sementes que as plantas estabelecidas em palhada de milho.
The objective of this research was to evaluate the production of sunflower in the off-season, supplemented or not with irrigation and cultivated after the crops of soybeans, corn or palisade grass. The treatments were allocated in a randomized blocks design in split plot (2x3), the supplemental irrigation by center pivot and without irrigation in the plots, and in the subplots the crops predecessors: soybeans, corn and palisade grass, with four replications. The height, stem diameter, shoot dry weight, number of leaves per plant and leaf area were evaluated at 15, 30, 45, 60, 75 and 90 days after emergence of sunflower plants. Sunflower plants were tall under all cultivation conditions, without variability in the evolution of stem diameter and of number of leaves. Leaf area was less in sunflower plants grown under corn straw and palisade grass under non-irrigated conditions. No significant effects on yield components - mass of thousand seeds, head diameter and oil and grain yield were observed. After cultivation of soybean, sunflower plants produced greater dry mass of shoots and higher oil content in the seed compared to plants established under corn stalk.
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