Soil organisms in organic and conventional cropping systems

Abstract

Despite the recent interest in organic agriculture, little research has been carried out in this area. Thus, the objective of this study was to compare, in a dystrophic Ultisol, the effects of organic and conventional agricultures on soil organism populations, for the tomato (Lycopersicum esculentum) and corn (Zea mays) crops. In general, it was found that fungus, bacterium and actinomycet populations counted by the number of colonies in the media, were similar for the two cropping systems. CO 2 evolution during the cropping season was higher, up to the double for the organic agriculture system as compared to the conventional. The number of earthworms was about ten times higher in the organic system. There was no difference in the decomposition rate of organic matter of the two systems. In general, the number of microartropods was always higher in the organic plots in relation to the conventional ones, reflectining on the Shannon index diversity. The higher insect population belonged to the Collembola order, and in the case of mites, to the superfamily Oribatuloidea. Individuals of the groups Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura and Symphyla were occasionally collected in similar number in both cropping systems. Key words: soil microorganisms, organic agriculture, microartropods, cropping systems, environmental impacts ORGANISMOS DO SOLO EM SISTEMAS DE CULTIVO ORGÂNICO E CONVENCIONALRESUMO: Apesar do crescente interesse pela agricultura orgânica, são poucas as informações de pesquisa disponíveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrófico foram comparados os efeitos de sistemas de cultivo orgânico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populações de fungos, bactérias e actinomicetos, determinadas pela contagem de colônias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO 2, manteve-se superior no sistema orgânico, sendo que em determinadas avaliações foi o dobro da evolução verificada no sistema convencional. O número de espécimes de minhoca foi praticamente dez vezes maior no sistema orgânico. Não foi observada diferença na taxa de decomposição de matéria orgânica entre os dois sistemas. De modo geral, o número de indivíduos de microartrópodos foi superior no sistema orgânico do que no sistema convencional, refletindo no maior índice de diversidade de Shannon. As maiores populações de insetos foram as da ordem Collembola, enquanto para os ácaros a maior população foi a da superfamília Oribatuloidea. Indivíduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas. Palavras-chave: microbiota do solo, agricultura orgânica, microartrópodos, sistemas de cultivo, impacto ambiental

Effect of Organic and Conventional Farming on the Activity of Spider Assemblage (Araneae) in Some Medicinal Plants in Fayoum-Egypt

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Diversity and association of filamentous fungi in coffee beans under organic and conventional cultivation

“…In Brazil, conventional farming is dependent on the use of herbicides, pesticides, and inorganic nutrient applications, whichare less beneficial to the environment than organic methods (Bettiol, et al, 2002).In contrast, organic coffee is produced without the use of pesticides and soluble fertilizers, which are replaced by recycling organic by-products such as animal manure, biofer-tilizers, pulp and coffee husk compounds, and earthworm castings (Theodoro and Guimarães, 2003). For the production of coffee to be considered organic, the crop must be free from the use of pesticides and chemical fertilizers for at least three years (Bakutis et al, 2006).…”

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