North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

Michael, how can you tell the difference from a chlorosis derived from
excessive pH from one caused by poor drainage?.  I'm a little suspicious
that those low points may have been like low points in many fields-
possessing poor drainage.  Of course this is an obvious observation that
was probably explored.

Here in the northeast woodchips are often used to mulch blueberries in home
orchard settings, which is all I'm knowledgeable about and I fail to see
why they should ever create problems- relatives like rhododendrons are
routinely mulched with shredded wood as well and these plants thrive under
this treatment at scores of estates I've seen. .  The only trouble I've
had  with shredded wood is that it sometimes mats up and excludes rain
water- it just runs off the surface.

I don't completely trust the kind of anecdotal examples you supply (not
that I'm not offering the same thing with much smaller scale examples).
I'd need a lot more info about how mulch was applied and what the weather
and soil issues were- actually I'd need to see the site myself to be
satisfied.  Always the problem with contradicting anecdotes.

Here are several mostly landgrant university guidlines that do recommend
mulching blueberries with woodchips.  I'd be interested in any research
based info you have on the affects of mulching blueberries with woodchips
as I couldn't find any actual research on the subject.

http://mysare.sare.org/mySARE/ProjectReport.aspx?do=viewRept&pn=FNC97-193&y=1998&t=1

http://mysare.sare.org/mySARE/ProjectReport.aspx?do=viewRept&pn=FNC97-193&y=1998&t=1

http://www.ces.ncsu.edu/hil/hil-8207.html

http://www.ipm.iastate.edu/ipm/hortnews/2001/3-23-2001/blueberries.html


>
>I have no doubt that what you say about humic acid production and mulching
blueberries may be true, but there are a lot of >variables at play, such as
what kind of mulch, or what kind of wood chips, and where the trees grew
etc.? Just as there are exceptions to every rule, there are circumstances
in which blueberries can be successfully grown in soils with a pH range
higher than the 4.5-5.5 typically recommended; however, as a general
guideline, most people will have the best shot at success if they follow
this.? I have been to literally hundreds of different blueberry operations
over the years, both in the NW and elsewhere?(there's more than 30,000
acres in blueberry production within a 45 minute drive of my house) and the
one thing I can say is that I absolutely cannot recommend wood chips as a
mulch for blueberries.? While some people may have success with it
elsewhere, in this area, every single field I've seen where they have
mulched with wood
 chips or hog fuel, has underperformed, often times in comparison with the
same variety being grown by the same person just a few rows away with
conventional treatments of compost and sawdust.? As I've said, there are
always exceptions.? In Georgia and Florida, most of the commercial
blueberry production takes place in pine bark substrate, or with
incorporated pine bark in the soil.? They have developed a system where
this works for them, although they still have to acidify the soil.? In fact
one very large blueberry farm I visited in Florida last month was growing
primarily in a pine bark incorporated and mulched system with sulfuric acid
in the water to help acidify, and they still had iron deficiency in some
low spots in their fields.? It turns out that these spots were where there
were limestone tailings near the surface that had been left there decades
before, and they just couldn't get the soil and water acid enough in these
places to avoid
 nutrient problems.
?
Every site is different and not all wood chips or other materials are the
same, and different cultivars certainly have a range of tolerances for
differing soil conditions and production practices.? I encourage people to
try to get their conditions as close to what the recommendations are as a
start, because I believe this will be their best chance for success.?
Having said that, sometimes you have to improvise and experiment to find
another solution, and I encourage people to do that too.
?
Michael