ABSTRACT. Studies regarding soil quality and health often need to be up-to-date, as they feed new models for quantifying agricultural impacts on the environment. This study was established to understand how types of vineyard cultivation (organic and conventional) affect soil chemical and microbial attribute dynamics throughout different seasons. Vineyard management had a strong effect on chemical soil attributes. Organic carbon and phosphorus were 2.8 and 2.0 times greater, respectively, in organic vineyards than in conventional vineyards. Metabolic quotient (qCO2) values were lowest in summer and autumn, with an average of 2.31-2.49 µg C-CO2 h-1 g-1 soil, under organic management, indicating greater microbial growing efficacy. Regardless of season and sampling position, organic soil had a higher C microbial biomass than conventional vineyards, with values ranging from 179.79 to 284.71 µg g-1 soil, which were similar to those of the adjacent forest soil. Overall, there were increases in both the microbial and the chemical attributes of soil under organic vineyards compared relative to conventional management, which might have been due to the continuous input of organic matter, crop rotation, and alternative plant protection and fertilizer compounds used in organic farming.

ABSTRACT The aim of the present study is to evaluate the economic viability of tomato cultivation in a system of organic farming, and to compare it with the conventional farming system. The fixed and variable costs of both cultivation systems were calculated, as well as the costs of disease control with the application of alternative products and pesticides. The revenues were computed using commercial production and the direct sales price. The total cost per area was higher in the conventional system, while the cost per plant was greater in the organic system, since it used a lower plant population density. In the conventional system, 2.33 times more was spent on plant management, due to the fact that the number of sprayings was greater than that carried out in organic farming. We further find that companion planting with other species such as coriander, in addition to helping with the management of the main crop, is important for economic sustainability as it is an extra source of income. Considering the specificities of the two systems, the profitability of organic cultivation, even accounting for its lower productivity , could exceed that of conventional cultivation.

RESUMO Considerando a necessidade de alternativas que sejam eficientes e mais sustentáveis no tratamento pós-colheita, o presente trabalho teve como objetivo avaliar a interferência de subprodutos de Cymbopogon citratus aplicados à campo, em sistema orgânico de produção, na qualidade pós-colheita de tomate tipo italiano, comparando-os a frutos obtidos de sistema convencional. Os tratamentos aplicados na pré-colheita foram: Extrato aquoso bruto de C. citratus a 1%, 5%, 10% e 15%, Óleo essencial de C. citratus a 10 µL L-1, 100 µL L-1, 200 µL L-1 e 400 µL L-1, Citral a 10 µL L-1, 100 µL L-1, 200 µL L-1 e 400 µL L-1, testemunha com aplicação de água, Calda Bordalesa 1%, Crop-set - Improcop® e tomate cultivado em sistema convencional. Foram realizadas análises físicas (coloração, perda de massa parcial e total, volume, viabilidade e peso específico), químicas (pH, SST, AT e ratio) e sensoriais (firmeza ao toque, aparência geral externa, característica da polpa, aparência geral interna, aroma, textura, sabor, sabor estranho, doçura, acidez e qualidade global). Diferenças significativas foram verificadas na comparação entre os dois sistemas de cultivo, de modo que os frutos orgânicos apresentaram tendência em demorar mais para amadurecer, menor acidez, maior SST na avaliação final e maior ratio. Na análise sensorial receberam as melhores notas para os parâmetros acidez, textura, doçura e qualidade global.

ABSTRACT Considering the need for alternatives that are efficient and more sustainable during post-harvest treatment, the aim of this study was to evaluate the effect of by-products of Cymbopogon citratus applied in the field under a system of organic production, on the postharvest quality of the Italian tomato, comparing them to fruits obtained under a conventional system. The treatments applied pre-harvest were: crude aqueous extract of C. citratus at 1%, 5%, 10% and 15%; essential oil of C. citratus at 10 µL L-1, 100 µL L-1, 200 µL L-1 and 400 µL L-1; Citral at 10 uL L-1, 100 mL L-1, 200 uL L-1 and 400 uL L-1; control with an application of water; 1% Bordeaux mixture; Crop-Set - Improcop®; and tomato grown under a conventional system. The following analyses were carried out: physical (colouration, partial and total weight loss, volume, viability and specific weight), chemical (pH, TSS, TA and ratio) and sensory (firmness to touch, general external appearance, pulp characteristics, general internal appearance, aroma, texture, flavour, off flavour, sweetness, acidity and overall quality). Significant differences were found in comparisons between the two systems, where the organic fruit tended to take longer to mature, had lower acidity, higher TSS in the final evaluation, and a higher ratio. In the sensory analysis, these received the best grading for the parameters of acidity, texture, sweetness and overall quality.

Este trabalho foi realizado no município de Maringá, localizado na região noroeste do Paraná, com o objetivo de analisar e comparar economicamente sistemas de produção orgânico e convencional de maracujazeiro-amarelo (Passiflora edulis Sims. f. flavicarpa Deg.). Para se montar a matriz de coeficientes técnicos, os custos de implantação e produção e os indicadores de lucratividade da cultura, os dados foram obtidos com extensionistas da região e baseados em trabalho de pesquisa, realizado na Fazenda Experimental de Iguatemi da Universidade Estadual de Maringá, no período de junho de 2002 a julho de 2004. O custo total de produção da cultura em dois anos agrícolas alcançou um valor 12,94% maior para o sistema convencional, e referente ao mesmo período, o índice médio de lucratividade foi 21,39% maior para o sistema orgânico. O sistema orgânico de produção se mostrou viável economicamente, proporcionando maior lucratividade.

This work was carried out in the city of Maringá, located in the Northwest region of Paraná, with the aim of analyzing economically the yellow passion fruit crop (Passiflora edulis Sims. f. flavicarpa Deg.), comparing organic and conventional production systems. To estimate technical coefficients, planting and production costs, and profitability indicators of culture, the data were surveyed from technicians of the region and based in experimental work, carried out at the Experimental Farm of Iguatemi from the Maringá State University, in the period of june/2002 to july/2004. The total production costs of the culture in two agricultural years reached a value 12.94% higher for the conventional system, and in this same period the medium index of profitability was 21.39% higher for the organic system. The organic production system was economically feasible and provided a larger index of profitability.

O experimento foi realizado no Departamento de Produção Vegetal da Escola Superior de Agricultura "Luiz de Queiroz", ESALQ/USP, Piracicaba, São Paulo, Brasil, utilizando-se as culturas de guaranazeiro (Paullinia cupana Kunth), cafeeiro (Coffea arabica L.), cajueiro (Anacardium occidentale L.), goiabeira (Psidium guajava L.) e seringueira (Hevea brasiliensis Muell. - Arg.). No período de seca (setembro/94) e de chuvas (novembro/94), realizaram-se determinações de resistência estomática (RE) (s cm-1) e transpiração (T) (µg cm-1 s-1) nas diferentes espécies. O delineamento experimental foi em blocos casualizados com cinco repetições. A partir das análises dos dados pode-se concluir: 1. diferenças significativas entre espécies, em termos das variáveis avaliadas no período de deficiência hídrica, com valores decrescentes de resistência estomática e crescente de transpiração na seguinte ordem: guaranazeiro > cafeeiro > cajueiro > goiabeira > seringueira; 2. Nas águas as diferenças entre espécies, para ambas as variáveis, foram menos evidentes, continuando a cultura da seringueira a apresentar menor resistência estomática e maior transpiração dentre as espécies; 3. As culturas de guaraná e café apresentaram maior resistência à perda de água, em relação às demais culturas.

During the dry and rainy seasons, determinations of stomatal resistance and transpiration of five tropical crops were carried out: guarana (Paullinia cupana Kunth), coffee (Coffea arabica L.), cashew (Anacardium occidentale L.), guava (Psidium guajava L.) and rubber (Hevea brasiliensis Muell. - Arg.) trees. Experimental design was done at randomized complete blocks with five replications. During the dry season there was a decrease in values of stomatal resistance in the following order: guarana > coffee> cashew> guava > rubber, with values from 2.5 to 30.0 s.cm-1. During the rainy season the stomatal resistance values varied from 1.5 to 3.0 s.cm-1. The guarana and coffee crops showed higher resistance to water transpiration when compared to other crops. During the rainy season, the rubber tree continued to present lower stomatal resistance and, consequently, higher transpiration.

Mudas envasadas de Coleus blumei, com três meses de idade, foram submetidas a diferentes concentrações de cloreto de sódio (NaCl: 0,00; 0,25; 0,50 e 1,00%). Visando determinar a absorção osmótica, as mudas tiveram seus caules cortados a 10 cm acima do solo. Os caules remanescentes foram interligados a tubos de vidro por tubos flexíveis de borracha. Foram feitas leituras (cm) a cada 30 minutos dos níveis das colunas de água nos capilares, correspondentes às absorções osmóticas de água, sendo ao todo realizadas onze leituras. Em outro momento, mudas de C. blumei, com a mesma idade das anteriores, receberam as mesmas concentrações de NaCl descritas anteriormente, e, ao ar livre, foram avaliadas em termos de transpiração e resistência estomática, usando-se para isto porômetro LI 1600. Usou-se delineamento em blocos casualizados, com cinco repetições, submetendo-se os dados à análise de variância e regressão polinomial. Verificou-se para todos os tratamentos aumento da absorção osmótica até três horas após a adição das soluções. A partir desse momento observou-se reversão da absorção osmótica proporcional ao aumento da concentração salina, sendo esse efeito mais pronunciado em 1,00 % de NaCl, o que reflete perdas crescentes de água pelas raízes. No controle a absorção osmótica apresentou comportamento crescente e linear com o passar do tempo. A transpiração foi proporcionalmente reduzida com o aumento da concentração salina.

Three month old Coleus blumei plants in pots were treated with different NaCl concentrations: 0.00, 0.25, 0.50 and 1.00%. To determine the water osmotic absorption, the plants had their stems cut at 10 cm from the soil surface. The remaining stems were linked to glass tubes by flexible rubber tubes. Readings of the water column level in the glass tubes were performed at each 30 minutes, corresponding to the water osmotic absorption, with a total of eleven readings. Other Coleus blumei, with the same age, received the NaCl concentrations, and were evaluated under field conditions in terms of transpiration and stomatal resistance. A randomized complete block analysis was used with five replications. An increase of osmotic absorption was verified for all treatments up to three hours after application. Then a proportional reversion of osmotic absorption to the increases on saline concentration was observed, with a higher effect in the treatment with NaCl 1.00%, showing the increase of water loss by the roots. During this period time, the treatment showed a normal linear growth of the osmotic absorption. Transpiration was reduced proportionally to the increase of salinity concentration.