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Algae Control in Ponds With Barley Bales: On-site Results in Nebraska
by Roch Gaussoin, Department of Horticulture, UNL



Algal growth during the summer season in ponds can pose several problems.
The algae that grow in ponds used for irrigation can clog pumps, block
filters, cause odor problems, and is generally considered to be
aesthetically unacceptable. The proliferation of algae appears to be closely
associated with the level of nutrients, especially phosphorous, in the
water. High nutrient levels are often found in ponds and lakes associated
with parks, golf courses, housing complexes and industrial sites.

Conventional control of algae can be either mechanical or chemical. Both
methods can be expensive and inefficient. Depending on the pesticide used,
chemical control may limit irrigation use or harm non-target aquatic plants
and fish. In some instances the algae problem may increase over time if
competitive plants and algae-feeding fish are decreased.

Barley straw has been suggested for use in ponds for algae control, yet
minimal replicated scientific research exists to substantiate the observed
positive results. It is beleived that the barley, as it decomposes, slowly
releases hydrogen peroxide into the water at levels that are toxic to algae.
The Center for Aquatic Plant Management in the United Kingdom has the most
active efforts in the development of this method of algae control. Following
is a brief summary of their observations:

This method will not kill algae already present; the bales must be in place
prior to algae bloom.
The algae are suppressed best when the straw is decomposing in a
well-oxygenated environment.
How much straw is needed depends on the surface area of the pond. Pond depth
or volume does not appear to influence suppression.
One-half to 1.5 oz of barley straw per 10 square feet of surface area
(approximately 2-3 bales per acre) will provide good activity against the
algae. Higher rates have been shown to provide better algae control if the
problem is severe.
Too much straw can deoxygenate the water.
It is best if the straw is applied loosely so that water can move freely
through it. A cage or netting can contain the loose barley.
The barley works best when it is at or near the pond surface.
It is better to use multiple "barley stations."
Apply the straw in the fall or early spring; this will give the straw a
chance to rot and get ahead of the spring/summer algae blooms.
Water temperature will affect how quickly the bales will begin suppression.
At temperatures below 50 F, 6-8 weeks are required, at 70 F, 1-2 weeks are
sufficient.
Once active, the straw will remain effective for approximately six months.
No negative side effects have been reported; however, increased invertebrate
populations and improvement of gill development in fish from ponds where
barley straw was applied have been observed.

"Paul" wrote in message
...
Hi, i have string algae growing in my pond, right where the water is
returning from the filter.This is the only spot i see it growing. Any
ideas how to get rid of it or keep it from forming again?? Thanks in
advance.......