CYANIDE IN YOUR GARDEN Cyanide is one of nature’s most toxic substances, the most troubling form is non-organic metal cyanide found in industrial waste sites, near combustion sources (automotive exhaust, fire, cigarette smoke and solid waste incinerators), in waste waters from water treatment plants, iron and steel plants, organic chemical industries, in landfills and associated ground water and areas of road salt applications and run off.The presence of industrial cyanide in the soil can cause the formation of extremely stable metal-cyanide compounds that make essential metals found in the soil unavailable to surrounding plants.
There are more than 60 organic cyanide compounds, found in over 1000 food plants and over 2500 other plant species. Some plants produce cyanide, while other plants consume these compounds. The strength of the organic cyanide compounds found in plants are affected by the age of the plant, the part of the plant consumed, the season of the year, time of day, ecological factors- stress conditions and genetic variations.
The ability of plants to synthesize the cyanide compound cyanogenic glycosides is at least 300 million years old and played an important role in the evolution of life on earth and remains an important component to the home gardener.This ability to produce organic cyanide is found throughout the plant kingdom, including bacteria, fungi, ferns, gymnosperm (conifers) and angiosperm (flowering plants.)
These plants may be poisonous to both humans and livestock. But this depends on what percentage of cyanide compounds are found in the plants at any one time, how much is ingested, the size and species of the animal, the speed of consumption, and the ability of the animal to detoxify the compounds. The amount of water an animal consumes while eating poisonous plants will also affect how much cyanide is absorbed.
Through evolution plants developed multiple defenses such as thorns, allergens, thick membranes and chemical compounds to ward off the attacks of bacteria, fungus, pathogens, herbaceous insects and animals. As these species co-evolved with the plants, some of them were able to turn this chemical warfare to their advantage. Cyanide produced by plants is a naturally biodegradable compound. There are bacteria, fungus and other microorganisms found in soil, which proliferates in the presence of organic cyanide. Some of these organisms have evolved to produce enzymes that are able to break down cyanide and use it as a nitrogen source.
In natural conditions some plants growing in a healthy environment will produce complex sugars and cyanide compounds and exchange them with the roots for nitrogen, essential minerals and water. These complex solutions will be transported to the soil, where the actions of soil microbes ensure that high levels of cyanide do not persist or accumulate.
Cyanide can be absorbed into clays and biological solids, such as mulches, but is considered relatively insignificant. A few garden insects millipedes, rollypollies, centipedes and beetles that live in your garden mulch, eat and then synthesize the remaining organic cyanide compounds and metabolize it through their excrement into ammonia, carbon dioxide and nitrogen.
After the small amounts of organic cyanide enters the soil from the plant, it will take 10 days to degrade. But only if there is sufficient amounts of organic carbon available to support the soil’s microorganisms.