RESUMO:Ao utilizar o solo como forma de tratamento e de disposição final de águas residuárias de café (ARC) e essa como fonte de água e de nutrientes para os cafeeiros, solucionam-se problemas ambientais e diminuem-se os custos de produção para o cafeicultor. Este trabalho teve por objetivo avaliar os efeitos de diferentes doses de potássio aplicadas via ARC no crescimento vegetativo de cafeeiros (Coffea arabica L.), 'Catuaí' e 'Catucaí', em , aplicadas via ARC, e pela testemunha (água de irrigação e adubação convencional). ARC com concentrações até 135 mg L -1 de potássio contribui para o crescimento vegetativo do cafeeiro, especificamente, altura de planta e diâmetro do ramo ortotrópico, mostrando-se igualmente, ou melhor, que a água de irrigação e potássio por meio da adubação convencional. Além disso, o aumento na concentração de potássio do solo em todos os tratamentos não foi suficiente para aumentar a condutividade elétrica em níveis que possam afetar o crescimento da planta, no período avaliado. PALAVRAS-CHAVE: potássio, reúso, Coffea arabica L. EFFECTS OF PROCESSING COFFEE WASTEWATER ON FIRST YEAR COFFEE PLANTS GROWTHABSTRACT: Using the soil as a form of treatment and final disposal for coffee wastewater (CW), considering its water and nutrient content to the coffee, solves environmental problems and reduces production costs for coffee growers. This research had the objective to evaluate the influence of different potassium levels from WC on the growth of (Coffea arabica L.), 'Catuaí' and 'Catucaí' coffee varieties, in their fist year, as well the potassium increase and electrical conductivity in the soil solution. The experiment was carried out in a greenhouse of the Engineering Department, of Universidade Federal de Lavras, in Lavras -MG, Brazil. The treatment levels were defined as: 30 mg L -1 ; 65 mg L -1 ; 100 mg L -1 ; 135 mg L -1 of potassium (K + ), applied through CW and the control (irrigation water and conventional fertilization). Coffee processing wastewater with concentration up to 135 mg L -1 of potassium contributes to coffee growth, specifically, plant height and shoot diameter, showing to be equal or even better than irrigation water and potassium via conventional fertilizers. In addition, during the period evaluated the increase in soil potassium concentration was not enough to increase electrical conductivity to levels that could affect plant growth.
Many studies have demonstrated the beneficial influence of nitrogen doses on corn dry grain yield and green ear yield. Due to a growing concern with environmental degradation, many agricultural practices, adopted in the past, are being reexamined. With regard to weed control, strategies that employ mechanical control, including intercrops, are being the object of renewed interest. The purpose of this study was to evaluate the effects of the application of nitrogen doses (0, 40, 80, and 120 kg N ha-1; as ammonium sulfate) and weed control on the growth, green ear yield, and grain yield of the AG 1051 corn cultivar. A randomized block experimental design with split-plots and nine replications was adopted. In addition to nitrogen rates, the AG 1051 cultivar was submitted to the following treatments, applied to subplots: no weeding, two hoeings (at 20 and 40 days after sowing), and intercropping with gliricídia (Gliricidia sepium). Gliricidia was sowed at corn planting, between the corn rows, using two seedlings per pit, in pits spaced 0.30 m apart. Gliricidia did not provide weed control, and gave plant growth, green ear yield and grain yield values similar to the no weeding treatment. However, regarding the number of mature ears got, intercropping with gliricidia did not differ from the two-hoeing treatment. Weed control did not have an effect on plant height and number of marketable, husked green ears, with the application of 120 kg N ha-1; indicating that nitrogen improved the corn's competitive ability. The two-hoeing treatment provided the best means for total green ears weight, number of marketable husked ears, both unhusked and husked marketable ear weight, grain yield and its components than the other treatments. Nitrogen application increased corn growth, green ear yield, and grain yield, as well as weed green biomass, but reduced the stand and growth of gliricidia.
RESUMO:As perdas de água por evaporação e arraste em sistemas de irrigação por aspersão podem assumir valores consideráveis, reduzindo a eficiência do sistema. Os objetivos do presente trabalho foram avaliar a capacidade preditiva de cinco modelos empíricos para estimar perdas de água por evaporação e arraste em aspersores modelo NY-7 (bocais de 4,6 mm x 4,0 mm), trabalhando sob diferentes condições operacionais e ambientais, e ajustar modelos específicos para o aspersor NY-7. Comparando os resultados medidos em ensaios de campo, com os resultados simulados, foi possível concluir que os cinco modelos empíricos considerados apresentaram pouca ou nenhuma adequação, tanto para os ensaios com um único aspersor (quadrado do erro-médio de 5,27; 20,70; 5,07; 6,95 e 7,06% para os modelos empíricos 1; 2; 3; 4 e 5, respectivamente) quanto para os ensaios com linhas laterais contendo aspersores (quadrado do erro-médio de 7,41; 24,43; 6,72; 3,16 e 2,9% para os modelos empíricos 1; 2; 3; 4 e 5, respectivamente). Comparados aos cinco modelos empíricos considerados, os novos modelos ajustados apresentaram menores erros, indicando que a aplicação de modelos empíricos deve ser limitada às condições de operação (diâmetro de bocal, pressão de operação, etc.) similares àquelas em que os modelos foram desenvolvidos. PALAVRAS-CHAVE: modelos empíricos, eficiência de irrigação, modelagem matemática. SIMULATION OF EVAPORATION AND WIND DRIFT LOSSES, IN THE NY-7 SPRINKLER (4.6 mm x 4.0 mm), IN STATIONARY SPRINLER IRRIGATION SYSTEMSABSTRACT: Evaporation and wind drift losses during sprinkler irrigation may reach significant values, cutting system efficiency down. The present work aims: (a) to evaluate the ability of five empirical models in predicting losses of a NY-7 model sprinkler (nozzle of 4.6 mm x 4.0 mm), working under different operational and climatic conditions; and (b) to adjust specific models to the NY-7 sprinkler. By comparing measured values -obtained on field trials -with simulated ones, it was possible to conclude that, in general, the five considered empirical models presented little or no adjustment for the single-sprinkler outdoor tests (root mean square error of 5.27; 20.70; 5.07; 6.95 and 7.06% for empirical models 1; 2; 3; 4 and 5, respectively) as well as for the block irrigation outdoor tests (root mean square error of 7.41; 24.43; 6.72; 3.16 and 2.90% for empirical models 1; 2; 3; 4 and 5, respectively). When compared to the five considered empirical models, the new adjusted models showed lower errors, indicating that the application of empirical models must be limitated to working conditions (nozzle size, operational pressure, etc.) similar to the ones in which they were developed.
ABSTRACT:The objective of this study was to characterize water application rate, water application pattern width, flow rate, water distribution uniformity and soil loss caused by nozzles of the Low Energy Precision Aplication (LEPA) type Quad-Spray emitter. The study was carried out at the Hydraulic and Irrigation Laboratory of the Department of Engineering at the Federal University of Lavras, in Lavras, state of Minas Gerais -MG, Brazil. Twenty-two (22) LEPA QuadSpray emitter nozzles were evaluated, with nozzle diameter ranging from 1.59 to 9.92 mm. The experimental design used was entirely randomized, with three replications. Increasing values of nozzle flow rate ranging from 77.44 up to 3,044 L h -1 , were obtained with increasing nozzle diameter sizes. Application pattern width ranged from 0.56 up to 3.24m, according to nozzles diameter size. Low values of CDU (maximum of 35.73%) were observed when using the QuadSpray nozzles. Observed average water application rates covered the range between 68.05 mm h -1 (the lowest value that was obtained with the 2.38mm nozzle) and 258.15 mm h -1 (the highest value that was observed with the 9.92 mm). Average water application rates increased in a simple nonlinear function with the increase of nozzle size diameter. However, the weighted average increase in the amount of soil loss by erosion was not related to the increase of weighted average water application values.KEYWORDS: technical characteristics of the Quad-Spray, resizing of nozzles, erosive impact. CARACTERÍSTICAS DE DISTRIBUIÇÃO DE ÁGUA E PERDAS DE SOLO DE BOCAIS DO EMISSOR QUAD-SPRAY TIPO LEPARESUMO: Foi objetivo deste trabalho caracterizar a taxa de aplicação de água, largura do padrão molhado, vazão, uniformidade de distribuição de água e perdas de solo de bocais do emissor QuadSpray tipo Low Energy Precision Aplication (LEPA). O trabalho foi realizado no
Coeficientes de cultura (Kc) e crescimento vegetativo de Acaiá Cerrado associados a graus-dia de desenvolvimento Moisés Santiago Ribeiro; Elio Lemos da Silva; Débora Candeias Marques de Moura; Antônio Augusto Aguilar Dantas2Departamento de Engenharia, Universidade Federal de Lavras, Lavras, MG, moisessantiago@hotmail.com 1 Resumo Há uma tendência de utilização de variáveis meteorológicas que considerem o efeito climático sobre a duração das fases e desenvolvimento da cultura, como base para estabelecer os coeficientes de cultura (Kc). Este estudo teve por objetivo determinar os Kc e o crescimento vegetativo do cafeeiro (Coffea arabica L.), cultivar Acaiá Cerrado MG-1474, estabelecendo uma relação com graus-dia de desenvolvimento (GDD). O trabalho foi conduzido na área experimental da Universidade Federal de Lavras (UFLA), no município de Lavras-MG. A partir dos valores de evapotranspiração de referência (ETo) e evapotranspiração da cultura (ETc), determinaram-se os Kc. Foram realizadas avaliações de crescimento vegetativo e estabelecida a relação com as somas térmicas ou GDD. Apesar do bom ajuste do modelo linear aos dados de crescimento vegetativo em relação aos GDD, houve o efeito das datas de plantio sobre o crescimento da cultura. Os valores de coeficientes de cultura (Kc) estimados pelo modelo desenvolvido para as condições de Lavras foram de0,73 a 1,25 correspondentes aos intervalos de 700 GDD. UNITERMOS: Coffea arabica L., balanço hídrico, evapotranspiração máxima. RIBEIRO, M. S.; SILVA, E. L. da; MOURA, D. C. de M.; DANTAS, A. A. A.COEFFICIENTS OF CULTURE (KC) AND VEGETATIVE GROWTH OF ACAIÁ CERRADO ASSOCIATED TO GROWTH DEGREES-DAY 2 Abstract There is a tendency in using meteorological variables that consider the climatic effect on the durations of the culture development phases in order to establish the crop coefficients. This study aimed to determinate the crop coefficients and the vegetative growth of the Acaiá Cerrado MG 1474 coffee plant (Coffee arabica L.) establishing a relation with the growth degree-day (GDD). The work was carried out in the experimental area of the Department of Engineering of the “Federal University of Lavras”, Lavras, MG. By using the values of the reference evapotranspiration and the crop evapotranspiration, the crop coefficients were determined. Vegetative growth evaluations were made and a relation with the thermal sums or growth degree-day was done. Despite the good adjustement of the third-degree linear model using the data of crop coefficients related to growth degree-day, there was the effect of the planting dates on the culture growth. The crop coefficient values estimated by the model developed for the conditions of Lavras ranged from 0.73 to 1.25, corresponding to the intervals of 700 growth degrees-day.KEYWORDS: Coffea arabica, hydric balance, maximum evapotranspiration
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