Tracy Seale holding a bag of barley straw, demonstrated at a northern Alberta dugout.
Yes, using barley straw is an environmentally friendly option for reducing algae, one that fish farmers and dugout/pond owners may be interested in. In some places, barley is as abundant as algae, making it an inexpensive alternative when compared to chemical treatment or mechanical control.
Some time ago, barley straw was discovered to have useful qualities for controlling algal growth in ponds. The exact science is still not understood, however, present research indicates a benefit to its usage with proper timing and application.
When barley straw is allowed to rot, processes are created within the pond or dugout that hamper algal growth. Decaying straw does not kill the algae already present, but it prevents new algae from forming. Barley straw is not considered detrimental to fish health or production.
Algae are considered bacteria, capable of fixing nitrogen from the atmosphere. This fixing of nitrogen combined with the limiting nutrient phosphorus, provided by runoff, allows algae to thrive in a number of Alberta's lakes, ponds and dugouts. Problems associated with algae blooms may include plugged water filters and water intakes, discoloration in water clarity, and foul odors. Algae blooms interfere with fishing, water recreation and can prove lethal by consuming all the oxygen and resulting in fish die off.
The time required for effective algae control varies with type of algae. Small unicellular species can disappear within 6-8 weeks. Larger filamentous algae can survive for longer periods and adequate control may not result in the first season if straw is added late.
Barley straw is only effective under oxygenated conditions. Thus, a square bale of barley is likely packed too tight to work directly. Breaking down the bale into one or more loose portions will allow the straw to properly absorb water and start a thorough rotting process.
Set-up is easy. The material will likely require weights and floats, since the straw will float until water logged. Once water-logged it becomes heavier than water, making removal of large bales quite challenging. Make sure all straw is contained in netting or wire to accommodate complete removal.
The recommended application rate is 10 g of barley straw for every square meter of water surface (see Algae Control in Ponds, fact sheet 485-7162 for further info).
The barley will require at least one month to set up (start rotting), and is generally active for about six months. To obtain best results, place your barley in the water during spring or fall (you won't want to change the barley during the winter when your pond freezes over).
Place new barley materials in the dugout a month prior to removal of the old straw. This keeps the cycle going with the fresh rotting barley always in your dugout.
Other straw types can be used, however, barley has shown the best results for algae situations.
Method for estimating amount of straw required.
1. Calculate the surface area of your pond or dugout
ie. 50 m x 30 m (1,500 m2)
2. Decide on the application rate of straw. Recommend 10 g per m2.
3. Multiply the area of the dugout by the quantity of straw required per m2 to obtain the total quantity required.
ie. 1,500 m2 x 10 g per m2 = 15,000 g =15 kg
4. Calculate the number of square bales. Divide the total weight of straw required by the weight of the bales (a small bale is usually about 20 kg).
ie. 15 kg / 20 kg = of a bale
5. Decide the weight of straw to be placed in each net. (The example below uses 3 kg). Then calculate the number of nets to be made.
ie. 15 kg / 3 kg per net = 5 nets
6. Decide the appropriate placement of the nets by spacing them out as evenly as possible. The spacing does not need to be exact.
|
Stephen Madden, AAFRD Agricultural Water
Specialist, Grande Prairie (780) 538-5606,
and
Tracey Seale, AESA Coordinator
MD of Clear Hills (780) 685-3925 |