Barley straw for ponds does not control algae and does not reduce muck, disease bacteria, odor or weeds and it does not improve fishing, boating or swimming. Barley straw for controlling algae was first publicized in England in the 1990s (1). CLEAN-FLO immediately performed tests on several algae-infested ponds, and water transparency did not increase. In some cases, water transparency declined. We at CLEAN-FLO believe that barley straw is neither an algaecide that kills algae nor an algae-stat that prevents more algae from growing. We believe that barley straw makes a haven for zooplankton that feed on algae, especially when the barley straw is loosely based. We believe that adding barley straw for ponds is just as unfavorable as dumping tree leaves into a lake or pond. It increases the fertilizer in the water.
Results at Purdue University (2) Maryland University (3) and Iowa State University (4) showed that some algae species were reduced by barley straw for ponds, while other species did not respond, or increased. Species that increased were mat-forming filamentous algae that zooplankton does not feed on.
Results at the University of Nebraska (5) showed that water quality remained poor and the lake became dominated by blue-green algae, a type of algae that zooplankton does not eat.
Studies at University of Florida (6) and at North Carolina State University (7) on pre-digested barley straw, which is supposed to increase whatever algaecide barley straw is supposed to release while it decomposes, were unsuccessful. Algae did not increase but remained at the same level. The University of Florida concluded that the amount of barley straw needed to control algae in ponds is too large for practical purposes.
Faulty Tests and Misinformation
Algae are the only parameter studied by some consultants as a measure of water quality. Three tests are used: water transparency which is a measure of the amount of algae in a lake or pond, chlorophyll-a which is a test of the amount of chlorophyll in algae, and total phosphorus which is the amount of phosphorus in algae that is tested by boiling the algae in acid. These tests do not consider the quality of a lake or pond by the amount of muck or the organic matter in muck, odor, aquatic macrophytes (weeds), disease bacteria, fish health and growth rate or number of fish, or by whether one can fish, swim or boat in a lake or pond. You can fish, swim or boat in a lake or pond if it has a lot of algae, but you cannot swim, fish or boat in a pond that has those parameters that are not considered as indicative of water quality.
If a consultant can reduce algae in a lake, he or she becomes a well-paid local hero, regardless of whether the lake has fish, muck, weeds, and odor and disease bacteria or is not swim-able, fishable or boat-able. This opens an opportunity for what is called biomanipulation. A faulty test of barley straw is if you kill the fish; algae will decrease because zooplankton feeds on algae and fish feed on zooplankton. If there are no fish, there are many zooplankton, so there are little algae. If there are not much algae and available phosphorus and nitrogen are still in the water, these fertilizers have to go somewhere, so they go into weed growth. Available phosphorus is phosphorus dissolved in the water. It is entirely different from total phosphorus, which is phosphorus found in algae. Total phosphorus is a measure of both available phosphorus and phosphorus in algae.
So if consultants put barley straw in a pond and kill fish at the same time, they are increasing the amount of zooplankton. The zooplanktons decrease the algae in the pond. The result is increased weeds and a lake that is not swim-able, not boat-able and not fishable.
Real Pond Restoration
Barley straw for ponds does not reduce muck, disease bacteria, odor or weeds and it does not improve fishing, boating or swimming, but Clean-Flo International gives you all these benefits.
- Newman, J. 1997. Control of Algae with Barley Straw. Information Sheet No. 3. Institute of Arable Crops Research, Center for Aquatic Plant Management. Berkshire, UK.
- Daniel E. Terlizzi, Maryland Sea Grant Extension Program, E-mail: [email protected]
- Joseph E. Morris, Iowa State University, E-mail: [email protected]
- John C. Holz, University of Nebraska, E-mail: [email protected]
- Kenneth Langland, University of Florida, E-mail: [email protected]
- Stratford Kay, North Carolina State University, E-mail: [email protected]