Effect of treated domestic sewage on the performance of a drip irrigation systemThe objective of this work was to study the effect of the use of treated domestic sewage on the performance of a drip irrigation system. Crude sewage was subjected to a treatment sequence and applied for 120 hours on a coffee crop. Drip flow and coefficients of uniformity and distribution were evaluated and clogging factors were identified. The results showed that biofilm formation inside drippers decreased the uniformity of application of the effluent and that filtration alone does not prevent clogging of emitters. Influência da aplicação de esgoto doméstico tratado no desempenho de um sistema de irrigaçãoNeste trabalho objetivou-se estudar o efeito da aplicação de esgoto doméstico tratado no desempenho de um sistema de irrigação por gotejamento. Para isso, o esgoto bruto foi submetido a uma sequência de tratamento e aplicado durante 120 horas na cultura de café, sendo avaliados a vazão do gotejador, os coeficientes de uniformidade e a distribuição. Foram também identificados os fatores causadores de obstrução. Concluiu-se que a formação de biofilme dentro dos gotejadores proporcionou redução da uniformidade de aplicação do efluente e que somente a filtração não previne a obstrução dos emissores. Palavras-chave:Gotejadores, água residuária, obstrução.

& Key message A histopathological study using one resistant and one susceptible clone of Eucalyptus urophylla × Eucalyptus grandis hybrid showed that the colonization of Ceratocystis fimbriata was limited by rapid and intense host defense responses such as closure of the vessel pits; formation of tyloses and gels; accumulation of amorphous material, starch, phenolic compounds, and calcium oxalate; and tissue lignification. The defense mechanisms of the resistant clone were not lethal to the pathogen because the fungus was reisolated from the diseased tissue. & Context The use of resistant genotypes of eucalypt is widely used to control Ceratocystis wilt caused by Ceratocystis fimbriata. However, little is known regarding the fungal infection process and the host defense responses. & Aims Thus, the objectives of this study were to compare the histopathological responses of one resistant and one susceptible clone of Eucalyptus urophylla × Eucalyptus grandis to artificial inoculation with C. fimbriata and to identify possible host defense responses against fungal infection. & Methods Fungal colonization was analyzed by light and scanning electron microscopy. The host defense responses to artificial fungal inoculation were evaluated through histochemical analysis and determining of the lignin concentration and lesion lengths, whereas the pathogen viability was confirmed by reisolations. & Results Both tested clones showed similar responses against fungal infection but presented defense responses with different speeds and intensities. Fungal colonization was not restricted in the tissue of plants from the susceptible clone, whereas in the resistant clone, fungal colonization was limited to the xylem vessels and parenchyma around the vessels due to closure of the vessel pits; intense formation of tyloses and gels; accumulation of amorphous material, starch, phenolic compounds, and calcium oxalate; and tissue lignification. However, the fungus was reisolated from the inoculated tissues of both clones.

Fertigation with wastewaters is a great option for reuse of effluents in agriculture. Domestic effluent can be reused after primary treatment, reducing treatment costs and pollution, also providing water and nutrients to crops. This work aimed to quantify the nutrients income in coffee crop fertigated with domestic sewage. Five treatments were used. T1 received only clean water, and treatments T2, T3, T4 e T5 received 180, 350, 480 Taubaté, v. 6, n. 3, p. 77-85, 2011 . (http://dx.doi.org/10.4136/ambi-agua.540) 78

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