Fábio Palczewski Pacheco

Substâncias húmicas do solo cultivado com plantas de cobertura em rotação com milho e soja

A materia orgânica (MO), principalmente suas fracoes, e indicadora da qualidade do solo e, na agricultura, esta relacionada ao aporte de material vegetal por meio de cultivos. Neste contexto, a adocao de sistemas de manejo que aumentassem o fornecimento de MO, consequentemente, melhorariam a qualidade do solo. Assim, neste trabalho foram avaliadas alteracoes nos teores de MO e substâncias humicas em um LATOSSOLO VERMELHO Eutroferrico, cultivado com plantas de cobertura em rotacao com milho e soja. Em 2010, sob sistema de plantio direto, foram implantadas as plantas de cobertura mucuna ana (Mucuna deeringiana), feijao guandu anao (Cajanus cajan) e crotalaria juncea (Crotalaria juncea). Em 2011 foram implantadas as culturas do milho e as plantas de cobertura canola (Brassica napus), crambe (Crambe abyssinica) e nabo forrageiro (Raphanus sativus) e, em sequencia, a cultura da soja. O teor de MO e carbono das fracoes humicas foram determinados anteriormente a implantacao, apos o manejo da cobertura vegetal e apos a colheita dos cultivos. No ano agricola 2010/2011, apos manejo das plantas de cobertura leguminosas, observaram-se alteracoes na concentracao total de substâncias humicas do solo. Em 2011/2012 houve incremento no teor de carbono e alteracao no teor de acidos fulvicos. Dessa forma, as plantas de cobertura proporcionaram mais carbono na fracao acidos fulvicos que contribui com aspectos de fertilidade do solo (CTC). O manejo com as plantas de cobertura, leguminosas e brassicaceas, e o cultivo de milho e soja aumentaram teor de MOS em um curto periodo de tempo, sendo o manejo considerado adequado para as condicoes estudadas.

The insecticidal potential of Foeniculum vulgareMill., Pimpinella anisum L. and Caryophillus aromaticus L. to control aphid on kale plants

The use of natural substances for pest control in agriculture is, economically, a viable option and has benefits for both the humanbeing and the environment, due to its low persistence and toxicity. Thus, this trial aimed on determining the insecticidal potential of the extracts and essential oils of fennel (Foeniculum vulgare Mill.), anise (Pimpinella anisum L.) and clove (Caryophillus aromaticus L.) to control Brevicoryne brassicae L. in kale (Brassica oleracea var. acephala DC.). The treatments were: fennel, anise, cloves extracts at 10%; fennel, anise, cloves oils at 1% and control with distilled water. The mortality tests were carried out with aphids in laboratory, with three replications, after 1, 12, 24, 48 and 72 hours. During laboratory trials , it was found out that fennel oil at 1% showed the best rate of mortality on aphid nymphs (70% at 72 h), followed by clove extract at 10% with 37% mortality. Tests in pots were only carried out only with cloves extracts at 10% and fennel oil at 1% treatment, in which such efficiency was alsoindicated on aphid nymphs.

USE OF YIELD AND TOTAL SOLUBLE SOLIDS/TOTAL TITRATABLE ACIDITY RATIO IN ORANGE ON GROUP DEFINITION FOR STANDARD DRIS

The nutritional quality of orange influences directly on its juice quality. Therefore, the DRIS (Diagnosis and Recommendation Integrated System) allows the verification of nutrients balance in plants as well as determine if its growth is associated or not to nutritionals restrictions. Thus, this research applied the total soluble solids/total titratable acidity to identify the standard group and to define the DRIS. The experiment was carried out in an orange orchard (1 ha) of the Monte Parnaso variety, in Southern Brazil. Twenty trees were geo-referenced, aiming to collect samples for foliar analysis and quantify fruits quality parameters. Therefore, it was possible to observe that total soluble solids/total titratable acidity presented the best ratio with the nutritional balance index, when compared to yield. Hence, it presents the best response when choosing standard group for DRIS calculations.

Common bean seeds quality during storage under treatments with potential repellent of aromatic plants

ndustrial chemicals that control pests in stored seed can cause damage to health by residual effects remaining in the grains. Studies of products with potential insecticide and repellent properties are required to decrease post-harvest losses. Thus, the aim of this study was to evaluate the quality and efficiency of seed treatment in beans stored under the following treatments: dried leaves and crushed laurel (Laurus nobilis L.), rosemary (Rosmarinus officinalis L.) and basil (Ocimum basilicum L.), cinnamon powder (Cinnamomum zeylanicum Breyn) and ground cloves (Syzygium aromaticum L.) over eight months. An untreated control and a treatment with diatomaceous earth were used to compare the results. At the beginning and at 30 days, percentages of normal and abnormal seedlings as well as seeds that did not germinate, mass of onehundred seeds, water content and infested seeds were analyzed. At 210 and 240 days, free choice arena and repellency testswere conducted. Treatments did not affect germination, mass of 100 seeds or water content; however, all plants tested showed a repellent effect on the bean weevil.

Allelopathy of Bidens sulphurea L. aqueous extracts on lettuce development

Allelochemical compounds are present in tissues of different plants` parts and also in other organisms, being released into the environment and thus affecting plants development. There is evidence that secondary metabolites produced by weeds may exhibit several allelopathic effects. This study aimed to evaluate allelopathic activity based on the interaction of aqueous extracts preparations and their concentrations obtained from Bidens sulphurea (Cav.) Sch. Bip. leaves on germination and seedlings development of Lactuca sativa L. cv. Grand rapids (lettuce). The extracts were obtained from fresh leaves and prepared by infusion, decoction, leaching and grinding methods, at concentrations of 0, 7.5, 15, 22.5 and 30%, with four replications with 25 lettuce seeds. Seven days after the percentages of abnormal seedlings and germination, shoot and root length (cm) were evaluated, while germination speed index (GSI) was daily determined and calculated. The experiment was completely randomized in a 4x5 factorial design, with four extract preparation methods and 5 concentrations. It was found out that the B. sulphurea aqueous extracts did not affect the germination and abnormal seedling development percentages in lettuce seeds. The aqueous extracts and their concentrations showed allelopathic effect for GSI, shoot and root length variables, despite their methods of preparation. This effect is not only inhibitory, but in some cases it was also stimulatory.

Allelopathy of Crotalariajuncea L. aqueous extracts on germination and initial development of maize

espanolEl objetivo de la investigacion fue evaluar el potencial alelopatico de los extractos de crotalaria sobre la germinacion y el crecimiento inicial de maiz. Los ensayos se realizaron en el laboratorio y en el invernadero con cuatro concentraciones (0; 7,5; 15 y 30%) para los extractos acuosos obtenidos por molienda y lixiviacion. En camara de la germinacion se observo que los extractos mas concentrados (15 y 30%) inhibio la germinacion de maiz y que la longitud de la parte aerea (LPA) se estimulo a una concentracion de 7,5%. Para el extracto de molienda hubo estimulacion en longitud de la raiz (LR) en todas las concentraciones ensayadas. El numero de raices (NR) se inhibio a concentraciones mas altas de extracto de lixiviado y estimulo para las semillas expuestas a extracto machacado de crotalaria. En invernadero, la longitud de la raiz mas larga (LRL) de maiz se inhibio a la mayor concentracion (30%) de los extractos de ambas maneras obtenidos. El extracto machacado inhibio los LPA en todas las concentraciones y la concentracion de 7,5% estimulo la NR. Se concluyo que los extractos de crotalaria mostraron efecto alelopatico en el desarrollo de maiz, que variaba de acuerdo a como se obtuvieron los extractos y concentraciones utilizadas. EnglishThe objective of this study was to evaluate the allelopathic potential of sunn hemp extracts on germination and initial development of maize. The trials were carried out in the laboratory and greenhouse with four concentrations (0; 7.5; 15 and 30%) of aqueous extracts obtained by grinding and leaching. In a germination chamber, more concentrated extracts (15% and 30%) inhibited maize germination, while shoot length (SL) was stimulated at 7.5% concentration. Ground extract stimulated root length (RL) at all tested concentrations. Root number (RN) was inhibited at higher concentrations of leached extract and stimulated for seeds exposed to sunn hemp ground extract. In the greenhouse, the longest root length (LRL) of maize was inhibited at the highest concentration (30%) of both extracts. The ground extract inhibited the LS in all concentrations and the 7.5% concentration stimulated the RN. It was concluded that sunn hemp extracts showed allelopathic effect on maize development, which varied according to how the extracts were obtained and concentrations used.