[nafex] mulching blueberries

Alan Haigh alandhaigh at gmail.com
Thu Dec 27 12:52:10 EST 2012

I pretty much agree with you Lee, although I can imagine an advantage to
finer mulch in that it would tend to decompose more rapidly than courser
stuff- this would presumably increase the release of humic acids and also
speed the presence of organic matter in the soil itself-  I just haven't
been convinced by Michael's explanations that this is in any way
established in actual research- he's spoken of but not directed us to any
of this- nor has he provided his own theory of why sawdust would be
superior to a courser product.  Knowing why is so important in actually
putting information to work effectively.  What if you have easy access to
free arborist wood chips and not to sawdust?   Some scale is needed to make
decisions in management.

Also, in my own plot, I've resorted to woven landscape fabric which I cover
with course wood chips (scraping off and replacing every couple of years,
putting the old chips below) and experienced no obvious change to their
growth and production, but it does apparently slow the poison ivy and
bindweed that I haven't been able to irradicate from the plot.  Is there
any research to back up the liability of landscape fabric that you
mention?  I have noticed that soil sometimes get very soppy immediately
under fabric.

Funny, I sent Michael a private e-maill a couple days ago and made the same
point as you do in your last sentence.  I had thought he'd respond to my
last post by saying that the drainage had been diagnosed at the low points
and found equivalent to the rest of the field.

Lee's comments    >"In my experience and understanding of what's going on
in the soil, over time there shouldn't be much difference on the effect
between any of the organic mulches. High C/N mulches do not tie up N
because their breakdown rate is mostly at the soil-mulch interface, so is
slow, with the subsequent mineralization rate about matching the rate at
which N is tied up. This theory matches my 30 years experiences with
mulching blueberries with various organic materials. I do add soybean meal,
1-2 pounds per hundred square feet to keep the plants vigorous; yields are
very good, about 11 quarts per plant.

I think the important thing is to mulch with any weed-free organic
material, without fussing between whether to choose one material or
another. A fabric weed barrier not only is usually ineffective for long
term weed control but also is counterproductive, interfering with
biological activity at the mulch-soil interface.

Also, chlorosis due to pH that's too high or poor drainage is the same.
Iron is not available to the plant in either case, with the resulting
interveinal chlorosis of youngest leaves first."

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