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| Adding silicon to nutrient solutions and growing media | |
| A recent news release from the ARS (Agricultural Research Service) of the USDA states that an increasing body of research suggests that silicon increases plant yields and protects plants from toxicity and fungal diseases. Modern greenhouse production methods have often eliminated ordinary soil as a growing medium thereby eliminating silicon, a mineral naturally found in soil. ARS scientists suggest that greenhouse growers might do well to add silicon to their nutrient solutions, irrigation or potting mixes. Over the past three years, horticulturist Jonathan Frantz and plant pathologist Jim Locke working at the ARS Greenhouse Production Research Group in Toledo, Ohio, together with other ARS and University of Toledo colleagues, have studied silicon uptake in a variety of ornamentals, including: Begonia, Dianthus, Pelargonium, Impatiens, Tagetes, orchids, Viola, Petunia, Antirrhinum, Verbena and Zinnia. X-ray analysis has shown that some of these genera, such as New Guinea Impatiens, Tagetes and Zinnia, accumulate silicon in significant concentrations in unique cells in their leaves. They found that silicon helps reduce symptoms of powdery mildew in Zinnia but has no effect on species such as Begonia and Pelargonium, which do not accumulate silicon. Finding suggest that by ensuring silicon availability, plants may have a reduced need for plant growth regulators, fungicides and insecticides. ARS scientists are continuing similar tests to see if silicon accumulates in the leaves of other ornamental crops and test those crops for silicon-induced resistance to insect pests. Currently James Locke is testing the effect of silicon uptake in Gerbera plants grown in soilless culture on resistance to powdery mildew. Such knowledge about the use of silicon by plants will help breeders choose promising lines for creating new varieties of flowers and ornamental plants that will need fewer pesticide applications. For further information: Don Comis, May/June edition of “Agricultural Research” or consult www.ars.usda.gov Also consult April edition of“FloraCulture International” www.floracultureintl.com and/or forthcoming editions of “Fruit &VegTec” www.hortiworld.nl In a larger context, it is worth noting the 4th Symposium on Silicon in Agriculture, due to be held in Brazil 19-20 June 2007. For further information, E-mail: phytus@phytuseventos.com.br www.phytuseventos.com.br |
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