Relationships between social forms of organic horticultural production and indicators of environmental quality: a multidimensional approach in Brazil

Organic farming (OF) is increasingly considered as a possible alternative for designing a "new rural" in Brazil, where OF covers a wide range of production and certification systems. However, the ways small farmers adopt OF in green belts to meet an urban demand in organic vegetables have not been extensively investigated. Likewise, the impact of such practices on environmental quality components has not been sufficiently documented. Our objective was to relate forms of organisation to environmental assessment in a watershed where organic horticulture significantly contributes to landscape and water quality. We showed how small farmers were organised or how they organised themselves to meet urban demands and develop OF. We assumed that associated practices were consistent with environmental impacts, as evaluated by indicators. Based on interviews with stakeholders, we identified four forms of organisation and associated farmers' practices. We related them to environmental assessment in three compartments: landscape ecology, water quality and soil quality. Although organisations share some objectives, namely with regard to visual quality and the "right price" of products, differences appear in their scope and internal operation, their values and relationships with consumers, and their technical and environmental contents. As for technical content, input supply, planning processes and crop diversity vary among organisations, ranging from liberal to hierarchical. Our results also showed similarities and differences among various organisations in terms of environmental impact. Such results are interpreted and discussed in the light of technical and social dimensions that account for the progressive design of new systems in Brazil

Efficiency of rice seed treatment with fungicides for controlling Helminthosporium oryzae

Com o objetivo de determinar a eficiência de fungicidas em tratamento de sementes de arroz (Oryza sativa L.), para controle de H. oryzae, amostra de sementes da cultivar IAC 47 com 46% de infecção, por esse fungo, foi tratada com os fungicidas abaixo relacionados nas seguintes dosagens de i.a., por kg de sementes: Thiram 70 P5 1750 mg; Captan 50 PM 1500 mg; Guazatine + Imazalil (30 + 2) L 0,64 ml; Iprodione 50 PM 1000 mg; Iprodione + Thiram (20 PM + 60 P5) 2000 mg e Imazalil 2,5 P5 87,5 mg. Com as sementes tratadas foi conduzido experimento de campo no município de Paulínia, SP, seguindo o delineamento experimental de blocos casualizados com 4 repetições. Os resultados mostraram que a maioria dos produtos reduziu significativamente o nível de infecção de sementes, sobressaindo em eficiência os fungicidas Guazatine + Imazalil, Iprodione e Iprodione + Thiram. Com relação a emergência e produção não foram observadas diferenças entre os tratamentos. Entretanto, análise efetuada com os parâmetros avaliados mostrou correlação significativa entre infecção de sementes e emergência e entre infecção e produção o que evidenciou a influência do tratamento de sementes sobre esses parâmetros. In order to verify efficiency of fungicides in rice seed treatment for controlling Helminthosporium oryzae, a seed sample of rice from cultivar IAC 47 with 46% fungus infection was treated with several fungicides and tested for health by the blotter method. The following products were used: thiram 70 dust, 1750 mg a.i./kg of seeds; captan 50 WP 1500 mg; guazatine + imazalil (30 + 2) L 0.64 ml; iprodione 50 WP 1000 mg; iprodione + thiram (20 WP + 60 dust) 2000 mg; imazalil 2,5 dust 87,5 mg. Most of the fungicides significantly reduced H. oryzae seed infection. The most efficient were: guazatine + imazalil, iprodione and iprodione + thiram. A field experiment was carried out in the 1983/84 growing season of with treated seeds in randomized plots with four replications. Although differences between treatments were not significant for emergence and production, negative correlation obtained for seed infection x emergence as well as for seed infection x production, showed influence of seed treatment on these parameters.

Avaliação do uso de métodos quimiométricos em análise de solos Evaluation of the use of chemometric methods in soil analysis

<abstract language="eng">One of the major interests in soil analysis is the evaluation of its chemical, physical and biological parameters, which are indicators of soil quality (the most important is the organic matter). Besides there is a great interest in the study of humic substances and on the assessment of pollutants, such as pesticides and heavy metals, in soils. Chemometrics is a powerful tool to deal with these problems and can help soil researchers to extract much more information from their data. In spite of this, the presence of these kinds of strategies in the literature has obtained projection only recently. The utilization of chemometric methods in soil analysis is evaluated in this article. The applications will be divided in four parts (with emphasis in the first two): (i) descriptive and exploratory methods based on Principal Component Analysis (PCA); (ii) multivariate calibration methods (MLR, PCR and PLS); (iii) methods such as Evolving Factor Analysis and SIMPLISMA; and (iv) artificial intelligence methods, such as Artificial Neural Networks

Qualidade do solo em sistemas de produção de hortaliças orgânico e convencional Soil quality in organic and conventional vegetables production systems

Sendo o solo um dos principais pilares de sustentabilidade de todo sistema de produção, a análise integrada dos atributos edafobiológicos pode constituir-se em ferramenta importante para avaliar a qualidade do mesmo. O objetivo do trabalho foi avaliar a qualidade do solo em função das práticas agrícolas adotadas, mediante a análise integrada de atributos físicos, químicos e biológicos. A pesquisa foi realizada em 2006 e 2007 nas microrregiões de Ibiúna e Socorro, no estado de São Paulo, em pequenas propriedades familiares orgânicas e convencionais. Foram avaliados os atributos físicos, químicos e biológicos, mediante coletas de amostras de solos sob cultivo de hortaliças e em solos de mata ou pastagem. O levantamento de dados sobre as práticas agrícolas foi realizado em cada sistema de produção. Os dados obtidos foram submetidos à análise de componentes principais (ACP). A ACP identificou maior grau de similaridade entre os solos sob cultivo em Socorro e suas respectivas testemunhas que os solos de Ibiúna, nitidamente separados em função do seu uso (mata ou cultivo) e indicando melhor manejo dos mesmos em Socorro. De maneira geral, concluiu-se que as práticas agrícolas utilizadas na maioria das propriedades orgânicas e convencionais favoreceram a degradação do solo, devida principalmente ao revolvimento intensivo e à ausência de cobertura do solo. Estes fatores provocaram redução dos teores de matéria orgânica do solo, da biomassa microbiana, da emergência de plântulas e da estabilidade de agregados nas áreas de cultivo em relação às áreas testemunhas.<br>The soil is one of the most important sustainability columns of the production system. The integrated analysis of the edaphobiological attributes can be an important tool for soil quality evaluation. We evaluated the soil quality regarding the adopted agriculture practices, using the integrated analysis of physical, chemical and biological attributes. The research was carried out in Ibiúna and Socorro, São Paulo state, Brazil, in organic and conventional production, on small and family farms. Physical, chemical and biochemical parameters were evaluated during 2006 and 2007 in soils under vegetable cultivation, native forest or fallow, taken as reference of natural soil. Agricultural practices data were collected in each production system. The obtained data were submitted to principal component analysis (PCA). There was no pronounced grouping trend according to the production system, organic or conventional, but there was a grouping according to the soil use (forest/fallow land or cultivation). The PCA identified greater degree of similarity between Socorro's cultivation soil and its respective controls compared to Ibiuna's soil, clearly separated according to its use (forest or cropping), indicating better soil management in Socorro. In general, the results allow to conclude that agricultural practices in most of both organic and conventional production systems, caused soil degradation, due to, mainly, intensive soil tillage and no soil mulching, as indicated by the reduction of soil organic matter, microbial biomass, plant emergence and aggregate stability in cultivated areas relative to control ones