Uso de polímero hidrorretentor na implantação de cafeeiros

The use of water retention polymers may be an option for ensuring water availability during the implementation phase of the coffee plantation. The experiment was conducted at Capao dos Oleos, Coqueiral municipality, Minas Gerais, in the period from 2009 to 2011. The aim of this study was to evaluate the effects of the water-retaining polymer which was previously hydrated for a better water supply, seeking to improve the survival and growth of coffee plants during the implementation phase of the culture in the field. A randomized block design was used in a factorial 4x3x2 was used with an additional treatment with four replications, totaling 25 treatments and 100 plots. Treatments consisted of four doses, three volumes and two areasof application of water retention polymers, plus an additional treatment as a control without the use of hydrogel. Growth evaluations were conducted in February 2010 and February 2011. The best form of application of the polymer was in the planting hole at the volume of 1.5 liters of solution composed of 1.5 kg of polymer diluted in 400 liters of water. After 476 days of the crop implementation there was no effect of the polymer application with a single dose on growth and survival of trees, opening up the discussion of possible viability of the reapplication of water retention polymers after crop implementation.A utilização de polímeros hidrorretentores pode ser uma opção para a garantia de disponibilidade de água na fase de implantação de cafeeiros. O experimento foi conduzido na Fazenda Capão dos Óleos, município de Coqueiral, Minas Gerais, no período de 2009 a 2011. Objetivou-se, no presente trabalho, avaliar os efeitos da aplicação do polímero hidrorretentor, previamente hidratado, no crescimento de plantas de cafeeiro na fase de implantação da cultura no campo. Foi utilizado o delineamento em blocos casualizados, no esquema fatorial 4x3x2 mais um tratamento adicional, com quatro repetições, perfazendo um total de 25 tratamentos e 100 parcelas. Os tratamentos foram constituídos de quatro doses, três volumes e dois locais de aplicação do polímero hidrorretentor, além de um tratamento adicional, como testemunha, sem a utilização do hidrogel. As avaliações de crescimento foram realizadas em fevereiro de 2010 e fevereiro de 2011. A melhor forma de aplicação do polímero foi na cova de plantio no volume de 1,5 litros da solução composta por 1,5 quilos do polímero hidrorretentor diluídos em 400 litros de água. Após 476 dias da implantação da lavoura, não houve efeito do polímero hidrorretentor com aplicação em dose única no plantio, no crescimento dos cafeeiros, abrindo-se a discussão de possível viabilidade de reaplicação do polímero hidrorretentor, após a implantação da lavoura

Fluorescence of chlorophyll a in pineapple plants submitted to herbicide applications

1 recurso en línea (páginas 50-58).El manejo químico de malezas con herbicidas es una actividad recomendada en cultivos, estrategia que permite un control eficaz para el cultivo de piña, que puede afectar su crecimiento y fisiología. De acuerdo a esto, el objetivo de este trabajo es evaluar el efecto de herbicidas de post-emergencia en parámetros de fluorescencia de la clorofila y tasa de transporte de electrones, relacionando la fluorescencia de la clorofila a en plantas de piña, variedad Imperial, así como, comprobar la intoxicación causada por estos productos. El experimento se realizó en campo en bloques aleatorizados en esquema factorial 5×2, siendo cuatro herbicidas (ametym, diuron, fluazifop y sulfentrazone) y el control (sin herbicida) y dos tiempos de evaluación (7 y 21 días después de la aplicación). El monitoreo de la fluorescencia de clorofila y las tasas de transporte de electrones también se llevaron a cabo a los 7 y 21 días después de la aplicación del tratamiento, siendo las variables: 1) fluorescencia inicial; 2) fluorescencia máxima; 3) relación de fluorescencia variable y fluorescencia total y 4) tasa de transporte de electrones. Los herbicidas evaluados afectaron negativamente el aparato fotosintético de las plantas de piña, el herbicida diuron seguido del ametryn fueron los productos que provocaron mayor estrés fisiológico en el cultivo. En la segunda época de evaluación, los efectos sobre el aparato fotosintético de las plantas se fueron intensificando, donde los productos probados redujeron los valores de la relación fluorescencia variable y máxima, indicando aumento del estrés causado por los herbicidas evaluados.The chemical management of weeds with herbicides is recommended for crops, a strategy that allows for the effective control of pineapple crops and that can affect growth and physiology. Accordingly, the objective of this study was to evaluate the effect of post-emergence herbicides on the fluorescence parameters chlorophyll and electron transport rate, relating chlorophyll a fluorescence in pineapple plants, Imperial variety, and checking for poisoning caused by these products. This experiment was carried out in the field in randomized blocks in a 5x2 factorial scheme, with four herbicides (ametym, diuron, fluazifop and sulfentrazone), a control (without herbicide) and two evaluation times (7 and 21 days after the application). The chlorophyll fluorescence monitoring and electron transport rates were carried out 7 and 21 days after the application of the treatment. The variables were: 1) initial fluorescence; 2) maximum fluorescence; 3) variable fluorescence ratio and total fluorescence; and 4) electron transport rate. The evaluated herbicides negatively affected the photosynthetic apparatus of the pineapple plants. The herbicide diuron, followed by ametrym, caused the greatest physiological stress in the crop. In the second evaluation period, the effects on the photosynthetic apparatus of the plants intensified, where the tested products reduced the values of the variables and maximum fluorescence ratio, indicating increased stress from the evaluated herbicides.Bibliografía y webgrafía: páginas 56-5

Ácido cítrico e fósforo no desenvolvimento e estado nutricional de mudas de café

In weathered soils, there is an increased retention of anions such as phosphate. Organic acids of low molecular mass have been shown an effective way to provide nutrients before it showed unavailable in the soil, such as phosphorus. The objective was to evaluate the quality and growth content of seedlings of ‘Catuaí Vermelho’ coffee (IAC-99), submitted the application of citric acid and phosphorus concentrations in the substrate. Was used the factorial scheme (4x4), being the first factor concerning the application of citric acid anidre to the substrate (0,0; 0,5; 1,0 e 2,0 mg dm-3), and the second concerning the doses of phosphorus (0, 450, 900 e 1800 mg P2O5 dm-3), in substrate. The experimental design was a randomized complete block with five replicates. The seeds were germinated in bags with standard substrate for coffee seedlings, adjusted according to the treatment with applications of phosphorus. Citric acid was applied when the seedlings had the cotyledons. The evaluation has been held at 180 days after sowing when the seedlings had four to five leaf pairs expands. Were measured the foliar levels, and fhytotechnical atributes and from these determined Dickson quality index. Doses of 1404.0 mg P2O5 dm-3 and 1.0 mg dm-3 of citric acid in the substrate positively influenced the maximum quality of the seedlings. Was not effective dose of 2.0 mg dm-3of citric acid for the development of the same quality to the point of planting, while increasing the concentration of Ca, N, P, S, Cu, Fe and Zn in the leaves.Em solos intemperizados existe um aumento da retenção de ânions como o fosfato. Ácidos orgânicos de baixa massa molecular têm sido eficazes para disponibilizar nutrientes considerados “indisponíveis no solo”, como o fósforo. Objetivou-se avaliar o desenvolvimento, a qualidade e o estado nutricional de mudas de café cultivar Catuaí Vermelho (IAC 99), submetidas à aplicação de diferentes concentrações de ácido cítrico e fósforo no substrato. Utilizou-se esquema fatorial (4x4), sendo o primeiro fator referente à aplicação de ácido cítrico anidro (0,0; 0,5; 1,0 e 2,0 mg dm-3) e, o segundo referente às doses de fósforo (0, 450, 900 e 1800 mg P2O5 dm-3), aplicadas no substrato. O delineamento experimental utilizado foi o de blocos casualizados, com cinco repetições. As sementes foram germinadas em saquinhos com substrato padrão para mudas de café, ajustado conforme os tratamentos. O ácido cítrico foi aplicado quando as mudas apresentavam as folhas cotiledonares. As avaliações foram realizadas aos 180 dias após a semeadura, quando as mudas apresentavam-se com quatro a cinco pares de folhas expandidas, sendo avaliados os teores foliares e atributos fitotécnicos e, a partir destes, determinado o índice de qualidade de Dickson. As doses de 1.404,0 mg P2O5 dm-3 e 1,0 mg dm-3 de ácido cítrico no substrato influenciam, positivamente, na qualidade máxima das mudas. Não foi efetiva a dose de 2,0 mg dm-3 de ácido cítrico para o desenvolvimento com qualidade das mesmas até o ponto de plantio, embora tenham aumentado os teores de Ca, N, P, S, Cu, Fe e Zn, nas folhas

Expansion of Planted Forests: The Risk of Pesticides Mixtures

Planted forests include forests established through human planting or deliberate seeding. They are systems that offer us timber and non-timber forest products and ecosystem services, such as wildlife protection, carbon sequestration, soil, and watershed maintenance. Brazil has 7.6 million hectares of planted forests, with 72% of the total area occupied by Eucalyptus spp. A favorable climate and management and genetic improvement research are the main factors responsible for high productivity. In recent years, the expansion of planted areas has been accompanied by the commercial release of several pesticides, mainly herbicides. A recent change in the Brazilian legislation allows mixing phytosanitary products in a spray tank, having a new approach to managing pests, diseases, and weeds. Antagonism is the main risk of tank mixes, and to reduce the dangers associated with this practice, we review all products registered for growing Eucalyptus. This literature review aims to identify the effects of product mixtures registered for Eucalyptus reported for other crops. In addition, environmental and social risk assessment has been widely adopted to export wood and cellulose, making the results of this review an indispensable tool in identifying the nature and degree of risks associated with pesticides. The results classify the effects of the mixtures as an additive, antagonistic or synergistic. The use of pesticide tank mixtures has the potential for expansion. However, there are still challenges regarding variations in the effects and applications in different climatic conditions. Therefore, studies that prove efficient mixtures for the forest sector are essential and the training of human resources