Biochar versus hydrochar as growth media constituents for ornamental plant cultivation

[EN] Biochar and hydrochar have been proposed as novel materials for providing soilless growth media. However, much more knowledge is required before reliable advice can be given on the use of these materials for this purpose. Depending on the material and the technology applied (pyrolysis or hydrothermal carbonization), phytotoxicity and greenhouse gas emissions have been found for certain chars. In this study, our aim was to assess the feasibility of three chars as substrate constituents. We compared two biochars, one from forest waste and the other from olive mill waste, and a hydrochar from forest waste. We studied how chars affected substrate characteristics, plant performance, water economy and respiratory CO2 emission. Substrates containing biochar from forest waste showed the best characteristics, with good air/water relationships and adequate electrical conductivity. Those with biochar from olive mill waste were highly saline and, consequently, low quality. The substrates with hydrochar retained too much water and were poorly aerated, presenting high CO2 concentrations due to high respiratory activity. Plants performed well only when grown in substrates containing a maximum of 25 % biochar from forest waste or hydrochar. After analyzing the char characteristics, we concluded that biochar from forest waste could be safely used as a substrate constituent and is environmentally friendly when applied due to its low salinity and low CO2 emission. However, biochar from olive mill waste and hydrochar need to be improved before they can be used as substrate constituents.This study was funded by the Polytechnic University of Valencia (Projects on New Multidisciplinary Research; PAID-05-12). We thank Molly Marcus-McBride for supervising the English.Fornes Sebastiá, F.; Belda Navarro, RM. (2018). Biochar versus hydrochar as growth media constituents for ornamental plant cultivation. 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Supressividade dos nematóides Meloydogine javanica e Heterodera glycines em soja por adição de lodo de esgoto ao solo Supressiveness of nematodes Meloydogine javanica e Heterodera glycines in soybean by sewage sludge incorporated in the soil

O lodo de esgoto, atendendo às exigências ambientais, apresenta grande potencial para utilização em solos agrícolas, onde vem sendo amplamente disposto. Sua utilização altera propriedades químicas, físicas e biológicas do solo, devido a sua composição em macro e micronutrientes e matéria orgânica. Estas alterações podem proporcionar benefícios como aumento da disponibilidade nutricional às culturas, indução de supressividade aos fitopatógenos presentes no solo e resistência às doenças da parte aérea. Por outro lado, pode influenciar negativamente o equilíbrio biológico e químico no solo, devido à presença de concentrações consideráveis de N disponível, sais solúveis e metais pesados. Com o objetivo de avaliar os efeitos da incorporação de lodo de esgoto ao solo sobre supressividade de nematoides de galha (Meloydogine javanica (Treub) Chitwood) e do cisto (Hetodera glycines Ichinoe), parasitas da soja (Glycine max L.), foram realizados experimentos em laboratório e casa de vegetação utilizando-se solo coletado de área experimental da Embrapa Meio Ambiente, Jaguariúna, SP. Esta área recebeu aplicações sucessivas de lodos de esgotos, originários das Estações de Tratamento de Esgoto de Barueri e de Franca, no Estado de S. Paulo, durante cinco anos (1998-2002). Com relação à indução de supressividade a nematóides, observou-se que o lodo de esgoto não afetou o desenvolvimento de fêmeas de H. glycines no solo (apenas reduziu o número de ovos por cisto) contudo reduziu a reprodução de M. javanica, nas raízes de soja.<br>Sewage sludge has shown great potential for use in agriculture, where it has been widely used. There are some modifications on chemical, physical and biological properties of the soil due to its composition of macro and micronutrients and organic substances. These alterations can provide benefits as an increase to the availability of nutrients to the plants, suppressiveness induction of soilborne plant pathogens and resistance to foliar diseases. However, it may influence negatively the biological and chemical balance in the soil, due to the presence of considerable amounts of available N, soluble salts and heavy metals. The aim of this work was to evaluate the effect of sewage sludge incorporation to the soil and the suppressiveness induction of nematodes (Meloydogine javanica (Treub) Chitwood and Heterodera glycines Ichinoe) in soybean (Glycine max L.). Experiments were performed in laboratory and in a greenhouse using collected soil in an experimental area of the Embrapa Meio Ambiente, Jaguariúna, SP. This area received successive applications of sewage sludge, originary from the sewage treatment of Barueri and Franca, in São Paulo State, Brazil, during five years (1998-2002). In relation to the suppressiveness induction of nematodes, the sludge did not affect significantly the development of H. glycines in the soil, but reduced the M. javanica reproduction, in the soybean root