Avaliação da qualidade microbiológica e produção de alface americana (Lactuca sativa L.) sob diferentes sistemas de irrigação, utilizando águas residuárias
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Data
2004-06-22
Autores
Azevedo, Leonardo Pretto de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A crescente expansão demográfica, o aumento da demanda por água potável, a elevação dos índices de poluição, o manejo inadequado de solos e florestas, e a contaminação de rios e lençóis freáticos têm causado sérios problemas ambientais, indisponibilizando grande porcentagem da água doce existente para utilização direta. Estima-se que apenas metade da população da América Latina seja beneficiada com redes de coleta de esgoto e que 90% deste volume coletado esteja sendo despejado em algum corpo de água superficial sem tratamento prévio. Como alternativa para este problema, grande quantidade de águas residuárias tem sido utilizada na agricultura, tornando imprescindível o desenvolvimento de novas tecnologias e métodos de aplicação segura destes efluentes na irrigação de produtos para consumo humano. Visando a necessidade de desenvolver técnicas seguras de aplicação de águas residuárias na agricultura, buscou-se no presente trabalho comparar parâmetros de produção, qualidade microbiológica e acúmulo de nitrato na cultura da alface americana, submetida à irrigação com água potável e com efluente de tratamento de esgoto doméstico, nos sistemas de irrigação por gotejo (superficial e enterrado), sulcos e microaspersão. A alface foi cultivada a campo, na Fazenda Experimental Lageado, da Faculdade de Ciências Agronômicas, localizada no município de Botucatu. As irrigações foram realizadas a cada 48 horas, durante os últimos trinta dias da cultura, repondo a lâmina evapotranspirada neste período. Verificou-se neste trabalho que os maiores valores de produção foram obtidos na irrigação por gotejo superficial, com águas residuárias. Quando comparada a influência do tipo de água utilizada em cada sistema, os valores de produção obtidos também foram maiores para a irrigação com águas residuárias no gotejo superficial, gotejo enterrado... .
The demographic expansion, the demand increase by potable water, the increase on pollution rates, the unsuitable soil and forests management, and the contamination of rivers and subsurface water have caused serious environment problems, and it became unavailable a high percentage of water for direct use. Only 49% of Latin American population has a sewer net; from this number, it was estimated that 90% hasn't been treated before being thrown away in a surface water source, causing more problems. A high quantity of wastewater has been used in agriculture as an alternative to this problem, what attracts the attention to the need of more researches about the development of a new technology and secure methods to apply effluents on irrigated crops to human consume. Counting on the possibility of develop secure techniques to apply wastewater in agriculture, this work had the aim of comparing American lettuce production, microbiological quality and nitrate level, using irrigation with potable water and domestic sewer treatment effluent, under drip (surface and subsurface), furrow and sprinklers irrigation systems. Lettuce was planted in a field, on Lageado Experimental Farm, Agronomical Sciences College, São Paulo State University, in Botucatu / SP, Brazil. The irrigations were carried out each 48 hours, during the last thirty days of the crop, adding the water rates lost in this period. It was verified in this work that higher production values were obtained with wastewater applied with surface drip irrigation. When comparing the influence of the kind of water used in each system, the production values also were higher on wastewater irrigation with drip irrigation (surface and subsurface) and furrows. On microbiological quality, only the lettuce irrigated by subsurface drip irrigation and furrows showed safe contamination values to fecal coliform and Salmonella, according to... (Complete abstract, click electronic address below).
The demographic expansion, the demand increase by potable water, the increase on pollution rates, the unsuitable soil and forests management, and the contamination of rivers and subsurface water have caused serious environment problems, and it became unavailable a high percentage of water for direct use. Only 49% of Latin American population has a sewer net; from this number, it was estimated that 90% hasn't been treated before being thrown away in a surface water source, causing more problems. A high quantity of wastewater has been used in agriculture as an alternative to this problem, what attracts the attention to the need of more researches about the development of a new technology and secure methods to apply effluents on irrigated crops to human consume. Counting on the possibility of develop secure techniques to apply wastewater in agriculture, this work had the aim of comparing American lettuce production, microbiological quality and nitrate level, using irrigation with potable water and domestic sewer treatment effluent, under drip (surface and subsurface), furrow and sprinklers irrigation systems. Lettuce was planted in a field, on Lageado Experimental Farm, Agronomical Sciences College, São Paulo State University, in Botucatu / SP, Brazil. The irrigations were carried out each 48 hours, during the last thirty days of the crop, adding the water rates lost in this period. It was verified in this work that higher production values were obtained with wastewater applied with surface drip irrigation. When comparing the influence of the kind of water used in each system, the production values also were higher on wastewater irrigation with drip irrigation (surface and subsurface) and furrows. On microbiological quality, only the lettuce irrigated by subsurface drip irrigation and furrows showed safe contamination values to fecal coliform and Salmonella, according to... (Complete abstract, click electronic address below).
Descrição
Palavras-chave
Alface - Irrigação, Aguas residuais de irrigação, Aguas residuais - Microbiologia, Nitratos, Lettuce, Effluent irrigation, Sewage irrigation
Como citar
AZEVEDO, Leonardo Pretto de. Avaliação da qualidade microbiológica e produção de alface americana (Lactuca sativa L.) sob diferentes sistemas de irrigação, utilizando águas residuárias. 2004. ix, 68 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2004.