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Substances with phytotoxic potential
High concentrations of mineral salts in solution within the growing medium can have phytotoxic effects. Sources of excessive mineral salts include infiltration of seawater and excessive application of fertilizers. For example urea is used in agriculture as a nitrogenous fertilizer, but if too much is applied, phytotoxic effects can result, either by urea toxicity or by the "ammonia produced through hydrolysis of urea by soil urease". Ammonia (NH3) converts into ammonium salts (NH4+), followed by oxidation into nitrites (NO2-)and nitrates (NO3-) by aerobic bacteria. The nitrous and nitric acid produced may be too acidic for the plant.
Herbicides are designed to kill plants, and are used to control unwanted plants such as agricultural weeds. However herbicides can also cause phytotoxic effects in plants that are not within the area over which the herbicide is applied, for example as a result of wind-blown spray drift or from the use of herbicide-contaminated material (such as straw or manure) being applied to the soil. The phytotoxic effects of herbicides are an important subject of study in the field of ecotoxicology.
- "Phytotoxicity - Pesticides". Province of British Columbia. 2007.
- Krogmeier, Michael J.; McCarty, Gregory W.; Bremner, John M. (1 November 1989). "Phytotoxicity of foliar-applied urea". Proceedings of the National Academy of Sciences of the United States of America 86 (21): 8189–8191. doi:10.1073/pnas.86.21.8189. PMC 298245. PMID 16594077.
- Joseph Jenkins, Inc. Publications Message Board
- Stefan Buczacki, Keith Harris (1998). "Disorders". Pests, Diseases & Disorders Of Garden Plants. Collins. p. 609. ISBN 0 00 220063 5.
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