Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Barley Straw??

I just spent the last couple of hours observing ponds in my region. Just seeing whether or not anything interesting was going on.

Every pond that I saw had the typical Eastern Nebraska late fall algae bloom. Nothing major, just lots of color in the water.

Then I visited one last pond and found the clearest looking water I've ever seen (outside of Shorty's pond). Easily ten feet of visibility. I tried to figure out what was special about this pond, and the only thing I could figure out was that this pond sat amidst about 100 trees that had shed their leaves into the water. I could count every single colored leaf on the bottom of the pond. It was really quite pretty.

My question is this. Might this be a similar phenomenon to barley straw's affect on water clarity and algae proliferation?

I wish I'd had my pH testing kit so I could see if the water was acidic.

Nobody really knows how barley straw works, right?

If it works in our water chemistry around here I'd sure be interested in trying it.

Bruce, are they mostly oak leaves or something else?

Nope - there are studies on BS and how it works from England IIRC. I will try to find one. Tannic acid ponds have clear water.

OK, my head hurts after reading this, let us know what you find ewest.

http://resources.cas.psu.edu/WaterResources/BarleyStraw.pdf

If I read that study correctly, it seems like my Dad's pond would only need ten to 100 pounds of barley straw. I would have never dreamed it was that little. Maybe I'd better do my calculations again. The pond is 6,000 sf, and has an average depth of 7 feet. That gives me about 40,000 cubic feet.

That equals about 1000 cubic meters, and the study says 5-50 g/cubic meter, or 5,000 to 50,000 grams of barley straw.

That's only 11 to 110 pounds. Geez! That ought to be relatively cheap compared to chemicals!

Not so fast guys.

Via Dave Willis.

BARLEY STRAW - ALGAE CONTROL

LITERATURE ANALYSIS

Evidence has been accumulating since the late 1970’s that barley straw

can be used to control nuisance blooms of algae in freshwater systems.

The most extensive use of this treatment has been in the British Isles,

where it has been used in lakes of varying sizes, potable water reservoirs,

canals, and streams (Barrett et al. 1999, Caffrey and Monahan,1999,

Harriman et al. 1997, Welch et al. 1990).



HOW BARLEY STRAW MAY WORK TO SUPPRESS

ALGAL GROWTH

It is still not clear exactly how barley straw suppresses algal growth.

There may well be more than one mechanism at work. The explanation

favored by several authors is that as the straw decomposes ("rots") under

aerobic conditions, phenolic compounds such as lignin, and especially

oxidized phenolics, are slowly leached into the surrounding water

(Everall & Lees 1997, Pillinger et al. 1994, Ridge & Pillinger 1996). Both

laboratory and field experiments have shown that barley straw releases

phenolic substances that both before and after decomposing suppress

algal growth (Everall & Lees 1997, Pillinger et al. 1994). The straw

exudates do not appear to bind nutrients or otherwise make them

unavailable, but this factor has not yet been investigated thoroughly.

It is not known why straw from other plants such as wheat have not

shown algistatic effects, even though these straws may also contain

significant levels of phenolics (Ball et al. 2001). This suggests that the

kind of phenolics (e.g., there are many different structural forms of

lignin) may be important, or perhaps accompanying substances affect

the way the phenolics break down. Algistatic effects have also been

demonstrated using decomposed leaves of deciduous trees such as oak,

which are high in phenolics, and also "brown rotted" wood, which

contains colored phenolic substances (Pillinger et al. 1995, Ridge &

Pillinger 1996, Ridge et al. 1999).

An alternative hypothesis for the effect of barley straw in suppressing

algae growth focuses on the straw as a carbon source added to a lake

system, not as a chemical inhibitor. This hypothesis appeared more

reasonable in the absence of detectable phenolic compounds following

effective straw application in a Minnesota lake. Barley straw provides a

carbon source for carbon-limited microbial growth. With the carbon

availability secure, the microbial community production soars - the noncyanobacteria

populations - and phosphorus uptake is shunted through

the non-cyanobacterial microbial loop ecosystem. The presence of

decaying barley straw therefore results in phosphorus limitation for

algae, not inhbitition by a released chemical compound (Anhorn 2005).

When barley straw has been used in North America, success in
controlling algae has not been so consistent, and the reasons for this
remain unclear (Nicholls et al. 1995, Lembi, 2001, Boylan & Morris
2003). The success of the method depends on a number of factors, all of
which must be properly addressed: starting treatment well in advance of
bloom development, adequate straw dosage, adequate aeration of the
straw, proper positioning of the straw in the body of water, adequate
water circulation, and perhaps the type (cultivar) of barley used and the
conditions under which the barley was grown. Nevertheless, even in
North America barley straw and barley extracts are being widely
promoted for eliminating nuisance algal blooms in ornamental ponds
(e.g. http://www.pristineponds.com/index.htm;
http://www.aquaticeco.com/index.cfm/fuseaction/product.detail/iid/14
4) Trials of other plant wastes for possible algistatic effects, e.g. ryegrass,

conifer needles, bark dust, juniper waste

Because other types of plant biomass besides barley straw (e.g. oak wood

and leaves) have been shown to release algistatic substances, it would be

worthwhile to assess the algistatic activity of other kinds of readily

available plant biomass. In Oregon, great quantities of ryegrass straw

are available, as well as conifer needles and bark dust from the forest

products industry. The recent push to remove juniper from rangeland

may present an opportunity to make this species easily available for use,

should it prove effective.

CODY Comment: No studies have addressed the affects of barley straw leachate on the various individual species of algae. In nature there are tens of thousands of differernt species of algae each with different tolerances to individual chemicals. This helps explain why some algae are affected more than others when they are exposed to barley straw.

Is it just me, or did Cornhusker Barley straw come in one pound bales at one time?

This makes me wonder if the dozen pin oaks we have on the north side of our pond plays a big role in keeping the water clear at our pond.

I have had decent success with barley straw controlling planktonic algae in smaller systems, but have had no luck controlling filamentous algae which seems to be a bigger problem for me.

Just remember the only people who are confident in barley straw are the people who sell it.

Lignins from numerous sources have long been associated with an algeastatic effect. Look through Wetzels treatise on Limnology. It has been documented decades before the puddle pond people started pushing straw.

Also beware of what you wish. Clear water has its own problems in shallow bodies of water.