One of the "natural" control methods that comes to mind is barley straw technology, and for greenhouse applications, barley extract.
Barley straw has gained considerable attention among farmers as a control of algae in farm ponds. Some of the initial research and information on this technology was developed at the Centre for Aquatic Plant Management in the UK, which is part of a national institute known as Centre for Ecology and Hydrology.
The following excerpts from the Centre's information sheet on barley straw explain the biological and chemical mechanisms that control algae as barley straw undergoes decomposition.
Information Sheet 1: Control of Algae with Barley Straw
Centre for Aquatic Plant Management, Centre for Ecology and Hydrology (UK)
Barley straw has gained considerable attention among farmers as a control of algae in farm ponds. Some of the initial research and information on this technology was developed at the Centre for Aquatic Plant Management in the UK, which is part of a national institute known as Centre for Ecology and Hydrology.
The following excerpts from the Centre's information sheet on barley straw explain the biological and chemical mechanisms that control algae as barley straw undergoes decomposition.
Information Sheet 1: Control of Algae with Barley Straw
Centre for Aquatic Plant Management, Centre for Ecology and Hydrology (UK)
The details of the exact mechanism by which straw controls algae has not been fully investigated, but it is generally accepted that the process may occur as set out below. Only a few of the compounds released from straw have been identified, the majority are known to be non-toxic while some may have slight toxic effects at the concentrations detected. It is likely that a combination of factors results in the anti-algal activity generated from decomposing straw.
When straw is first placed in water, the soluble components of the straw are washed out, causing water to turn a brown colour. These compounds have not been identified, but they are likely to be a mixture of carbohydrates and hemicelluloses. Bacteria are the most dominant micro-organism at this stage.
After about two weeks the dominant micro-flora change to fungi. This is when decomposition of lignin and other cell wall components starts to occur.
When straw rots, the cell wall components decompose at different rates. Lignin is very persistent and is likely to remain and be released into the water as the other components decay. Decomposition of lignin leads to the production of a form of soluble lignin and other decomposition products. These decomposition products are likely to be transformed by bacterial and fungal enzyme activity before being released in to the surrounding water. This mixture of compounds is transformed into fulvic and humic acids.
These humic substances are more easily referred to as Dissolved Organic Carbon or DOC. DOC is a natural component of many freshwater and marine ecosystems. When light shines onto water which contains humic substances, in the presence of dissolved oxygen, hydrogen peroxide is eventually formed.
High molecular weight DOC absorbs sunlight energy and can pass this energy to dissolved oxygen molecules. The dissolved oxygen becomes unstable and decomposes into two singlet oxygen radicals. These are very short lived, of the order of 1 micro-second, but extremely reactive molecules. The singlet oxygen radicals form superoxide radicals and these from hydrogen peroxide in water. The hydrogen peroxide is slightly more stable and persists for approximately 2 days in freshwater. The presence of a continuous supply of the right form of DOC creates conditions whereby hydrogen peroxide and the other oxidising agents can be continuously produced.
Concentration of hydrogen peroxide of only 2 ppm peroxide have been demonstrated to inhibit the growth of algae. Experiments have shown that sustained low concentrations of hydrogen peroxide can have a very similar effect on algae to that of straw.
There are various factors which affect the performance of straw and which support this hypothesis. It is important to take these factors into account to ensure successful treatment of algal problems with straw.
I've used this stuff for 2 grows and it seems to work. i'm wondering if anyone else uses it, and knows its effects on beneficials i.e.endomycorrizal fungi, mycorrhizae in calcined clay, a few other spores for the roots? oh, i use the extract which works exactly like straw...just like h2o2 but natural I think
I've used this stuff for 2 grows and it seems to work. i'm wondering if anyone else uses it, and knows its effects on beneficials i.e.endomycorrizal fungi, mycorrhizae in calcined clay, a few other spores for the roots? oh, i use the extract which works exactly like straw...just like h2o2 but natural I think
