Raul de Lucena Duarte Ribeiro

Desempenho do consórcio entre repolho e rabanete com pré-cultivo de crotalária, sob manejo orgânico

Field experiments were carried out during two consecutive years in the Integrated Agroecological Production System, in Rio de Janeiro State, Brazil, to evaluate the performance of cabbageradish intercropping under organic management on the basis of agronomic traits and Area Equivalency Index (AEI). The contribution of green manure pre-planting to the system also was evaluated. A randomized complete blocks design with seven replicates in a 2x3 split-plot factorial scheme was used. Treatments in the main plots consisted of Crotalaria juncea pre-planting or fallow. Cabbage or radish single crops and the respective intercropping were distributed in the subplots. No significant differences were detected between C. juncea and fallow as related to cabbage or radish yields in any of the systems used (single crops and intercropping). Intercropping had no effect on cabbage yield, but significantly reduced radish root yield. However, commercial standard of the harvested radish roots was not affected. An average AEI of 1,59 for the two experimental years was attained, thus indicating the viability of the cabbage-radish intercropping. The system makes possible to afford additional income for a given area cultivated with cabbage, at its conventional single-crop spacing, by including radish as a secondary crop. Intercropping also was advantageous by allowing optimization of cultural practices such as fertilization, weeding, and irrigation.

Plantio direto, adubação verde e suplementação com esterco de aves na produção orgânica de berinjela.

No-tillage systems were evaluated within an eggplant (Solanum melongena) organic management in Seropedica, Rio de Janeiro State. Crotalaria juncea and Pennisetum glaucum cv. BRS 1501 were used as pre- plantings besides fallowing, in comparison to conventional system (plowing). Simultaneously, three cropping managements were tested: eggplant single-cropping, intercropping with C. juncea, and intercropping with cowpea (Vigna unguiculata cv. Maua). No differences were found among planting systems concerning eggplant yield. Crotalaria juncea was more effective than Pennisetum glaucum and fallow for soil mulch. Intercropping with leguminous species did not decrease eggplant yield. In a second study no-tillage (on C. juncea and spontaneous weeds mulchs) and conventional plowing were compared. These treatments were combined with increasing levels of poultry manure (0, 100, 200, and 400 kg ha -1 of N). In terms of biomass input, C. juncea was again superior to spontaneous weeds. Eggplant responded to organic fertilization with maximum productivity (50.6 t ha -1 ) corresponding to the highest manure level applied, compared to 36.9 t ha -1 for control plots.

Consórcios alface-cenoura e alface-rabanete sob manejo orgânico

Two experiments were carried out, in two consecutive years, at Seropedica, RJ, Brazil, aiming to evaluate the agronomic performance of intercropping of lettuce cvs. Regina 71 (smooth leaf) and Veronica (crisp leaf) with carrot (cv. Brasilia) and radish (cv. Hybrid number 19), under organic management. The amount of nutrients exported from the system by harvesting was also evaluated. The experimental design used was of completely randomized blocks, with four replications. In the first experiment, treatments consisted of lettuce with crisp leaves intercropped with carrot, lettuce with crisp leaves intercropped with radish and sole crops. In the second experiment, lettuce with smooth leaves was used instead of lettuce with crisp leaves. Intercropping of carrot and lettuce, with crisp or smooth leaf, presented land equivalent ratios higher than 1.60. Intercropping of radish and lettuce, with crisp or smooth leaf, presented land equivalent ratios of 1.54 and 1.27, respectively. Besides, the amounts of nutrients extracted by harvested products were lower than the inputs, pointing out the viability of the tested intercroppings.

Primeiro registro de Lipaphis pseudobrassicae Davis (Hemiptera: Aphididae) e sua associação com insetos predadores, parasitóides e formigas em couve (Cruciferae) no Brasil

This study describes the fauna of predator insects, parasitoids and ants associated with aphids on kale (Brassica oleracea L. var. acephala D.C.) in organic system. The aphid was identified as Lipaphis pseudobrassicae Davis, and this is the first record of the species attacking kale in Brazil. Primary parasitism by Diaeretiella sp. and Aphidius sp. and hyperparasitism by Aphydencyrtus sp., Alloxysta sp., Pachyneuron sp. and Syrphophagus sp. were observed. Twenty species of Coccinellidae were collected, and eight of them were observed in adult and larval stages attacking the aphid: Hyperaspis (Hyperaspis) festiva Mulsant, which was the most abundant (72.5% of all predator insects obtained), Cycloneda sanguinea (L.), Eriopis connexa Germar, Coleomegilla maculata DeGeer, Hippodamia convergens Guérin, Heterodiomus sp., Scymnus (Pullus) sp.1 and Scymnus (Pullus) sp.2. Aphidophagous Syrphidae larvae collected on leaves ofkale infested by L. pseudobrassicae belong to the species Allograpta exotica (Wiedemann) and Ocyptamus gastrostactus (Wiedemann). Larvae and pupae of Syrphidae were parasitized by Pachyneuron sp., Syrphophagus sp. and Diplazon laetatorius Fabricius. Larvae of Chrysopodes sp. were observed feeding on L. pseudobrassicae. Species of ants associated with the colony of this aphid were Ectatomma quadridens Fabricius and Pheidole sp.

Avaliação de genótipos de Capsicum para resistência ao ácaro branco

Fifteen Capsicum accessions from the Vegetable Crops Germplasm Bank from the Universidade Federal de Vicosa (Brazil), one hybrid and four pepper cultivars were evaluated in greenhouse for resistance to the broad mite (Polyphagotarsonemus latus). The experiment was set in a completely randomized (split plot in time) design with six replicates per genotype. Evaluations were performed either by counting the number of adult mites present on leaf samples weekly collected or by a grading scale related to symptom severity on infested plants. Symptoms assessment was shown to be more suitable for separating genotypes in resistant or susceptible to the mite. The accessions BGH/UFV 1774 (C. annuum) and BGH/UFV 5086 (C. frutescens) were respectively ranked as resistant and highly resistant to P. latus under severe testing conditions.

Balanço do nitrogênio e fósforo em solo com cultivo orgânico de hortaliças após a incorporação de biomassa de guandu

The objectives of this study were to evaluate the efficiency of pigeonpea ( Cajanus cajan) biomass incorporation to the soil as well as the effect of presence or absence of pigeonpea hedgerows on soil fertility and productivity of three vegetables, beet, carrot and dwarf green bean. Samples were randomly taken in a block design with three replications for each crop. In the field, no other fertilization treatment was applied. In plots without biomass incorporation, nitrogen showed negative balance, whereas in the field with biomass incorporation a high positive N-balance was found. Concerning phosphorus, positive balances were determined in plots without biomass incorporation, however, the uptake of P increased significantly after biomass incorporation in all crops used. The results indicate that pigeonpea alley cropping system may represent an advantageous option for organic farmers to maintain or to improve soil fertility.

Manejo da irrigação associada a coberturas mortas vegetais no cultivo orgânico da beterraba

Praticas agricolas orgânicas, como a cobertura do solo com palha, foram testadas em area irrigada por gotejamento na Baixada Fluminense, no Estado do Rio de Janeiro. O cultivo de inverno da beterraba nesta regiao e favorecido por temperaturas mais amenas, coincidindo com a epoca de maior disponibilidade do produto no Estado. No cultivo da beterraba, foram adotados tres tipos de cobertura do solo e seis lâminas de irrigacao (0; 29; 48; 78; 100 e 148% da ETc) determinadas com base no balanco de agua no solo utilizando a tecnica da TDR. O delineamento estatistico adotado foi blocos casualizados, com seis tratamentos e quatro repeticoes. Sob cobertura morta de Pennisetum purpureum, de Gliricidia sepium e na ausencia de cobertura morta, os valores maximos relativos de EUA, no cultivo de beterraba, foram de 21,00; 32,90 e 17,90 kg m-3, respectivamente. A maior e a menor lâmina de irrigacao acumulada para cada tipo de manejo foram de 2.746 e 951 m3 ha-1 nas parcelas sem cobertura morta. Em comparacao, as parcelas com cobertura do solo reduziram em 34,5 e 10,5% as lâminas acumuladas, respectivamente. Os valores acumulados de nitrogenio nas partes das plantas foram maiores no cultivo sob cobertura morta de G. sepium, indicando vantagens desta pratica cultural associada a irrigacao por gotejamento.

Efeito do acibenzolar-S-methyl sobre murcha-bacteriana do tomateiro

The potential of acibenzolar-S-methyl (aSm) as a plant resistance activator was evaluated against tomato bacterial wilt caused by Ralstonia solanacearum. Plants of the cvs. Santa Clara, Diana and AF-2573 received seven weekly applications of aSm (2.5 g i.a./100 L water), by foliar sprays or soil drenches. The first application was carried out 14 days after sowing. 32-day old plantlets were transplanted into infested soil with R. solanacearum where they received four weekly applications of the activator. Control plots received only water. Disease severity was evaluated daily through the number of wilted leaves and plants. With the obtained data we estimated the area under the disease progress curve. Wilt symptoms increased at a slower rate in the three cvs. when aSm was sprayed. This effect was significant up to four weeks after transplanting in infested soil with R. solanacearum.

Cowpea and corn intercrops in organic farming system aiming at production of immature beans and spikes

No periodo de outono-inverno-primavera de 2007, foi conduzido um estudo em Seropedica, Regiao Metropolitana do estado do Rio de Janeiro (Baixada Fluminense), com o objetivo de avaliar diferentes tipos de consorcio entre caupi (cv. Maua) e milho (cv. AG-1051), em sistema orgânico de producao. O experimento foi instalado em area de Argissolo Vermelho-Amarelo no delineamento de blocos ao acaso, com quatro repeticoes. Os tratamentos constaram de diferentes epocas ou intervalos de tempo de semeadura do caupi em relacao a do milho, a saber: (E1) 21 dias antes do milho; (E2) 14 dias antes do milho; (E3) 7 dias antes do milho; e (E4) no mesmo dia do milho. Tratamentos correspondentes aos cultivos solteiros do caupi e do milho foram incluidos, ambos semeados na data do tratamento E4. O cultivo consorciado com o caupi nao interferiu na produtividade do milho em espigas verdes e tambem em termos de comprimento e diâmetro basal dessas espigas, independentemente do intervalo entre semeaduras. Com referencia ao caupi, a produtividade em graos verdes no cultivo solteiro foi superior a dos consorcios com o milho. Os valores obtidos para os Indices de Equivalencia de Area (IEA), foram todos acima de 1,0, indicando que os consorcios foram eficientes quanto ao desempenho agronomico/biologico. Considerando, ainda a produtividade de cada cultura participante do consorcio, a semeadura do caupi antecipada de 21 dias em relacao a do milho afigura-se mais adequada ao manejo orgânico adotado e as condicoes edafoclimaticas da regiao.

Desempenho da alface em cultivo orgânico com e sem cobertura morta e diferentes lâminas d'água

O experimento foi conduzido no periodo de 27/05/2006 a 02/08/2006 no SIPA (Sistema Integrado de Producao Agroecologica), localizado no municipio de Seropedica-RJ. Nesse trabalho, objetivou-se avaliar o desempenho da cultura da alface (Lactuca sativa L.) cultivada sob diferentes lâminas de irrigacao em um solo sem e com cobertura de palhada da leguminosa gliricidia. Foram conduzidos dois experimentos simultâneos, utilizando o delineamento experimental de blocos ao acaso, em ambos os experimentos, nos quais foram aplicadas 5 lâminas de irrigacao, correspondendo a 25, 50, 80, 100, 115 % da evapotranspiracao da cultura (ETc), sendo a producao final avaliada por meio da determinacao da massa fresca, area foliar e numero de folhas. Ate o nivel de 100% ETc, todas as variaveis analisadas tiveram seus valores aumentados, e para o nivel de 115%, houve um decrescimento das mesmas. Na producao de massa fresca total, o sistema de cultivo com utilizacao de cobertura morta foi superior ao sem cobertura nao diferenciando estatisticamente ao nivel de 5 % probabilidade pelo teste F somente nas lâminas de 25 e 115% ETc.