There has always been a great deal of anecdotal ‘evidence’ that the decomposition process of barley straw can suppress or control algae growth. If it works, this treatment is extremely attractive to pond and wetland managers because it is a completely natural process that cannot harm fish, plants, or people. The likely modes of action of decomposing barley’s effects have both chemical and biological components, and many environmental characteristics influence the rate and strength of barley’s efficacy.

SPROut has partnered with Oregon State University's Crop and Soil Science Department to research the use of barley straw to control algae. While OSU was busy doing replicated experiments in their laboratory with barley extracts, we were carrying out corresponding field trials at The Oregon Garden (in addition to further field trials at J. Frank Schmidt's Nursery) to attempt to answer these questions:

Can we prove that it works? Can we isolate the active substances in the decomposition process? Can we just produce barley extract in the lab and use that in the ponds instead of the messy bales? Can we explain the mechanism by which this whole process works? Is it just a chemical reaction or does it also depend on particular associations of beneficial bacteria that live on the decomposing barley? What environmental conditions are required for proper decomposition? How much aeration is necessary? Is the pH of the water a critical factor? How many bales are needed to treat a water feature of this size? How long does it take to work?

For more information on this research, visit the OSU barley team’s website at www.barleyworld.org or contact
Pat Hayes, Oregon State University, Crop and Soil Science
patrick.m.hayes@oregonstate.edu
541-737-5878

Barley straw extract tanks at OSU's lab

Barley bales in a wetland pond at The Oregon Garden

Barley logs in the filter trough of the A-Mazing Water Garden waterwall at The Oregon Garden