Kevin,
Bill Shane's comments are right on target. Excessive dust is a major
concern in an orchard setting and has led to several lawsuits here in
Colorado.
Effects of dust ( at least potential if not actual, from my perspective)
are as follows:
1. Increased risk of spider mite problems (increased attention to
control options).
2. Increased shading of leaves & fruit (through dust deposition) --
can decrease light uptake if thick enough,
leading to reduced fruit size and photosynthates (sugars) in the
fruit. I don't know what the actual
deposition depth required to do this would be -- that would be
extremely difficult to measure,
probably would need to be worked out in terms of lbs of dust
deposited / acre. There should be
some information on this somewhere as an outcome of the Mount.
St. Helens eruption in 1980
& following.
3. Reduced light can reduce bud production for the coming year and
winter/spring hardiness (like
shading of interior of canopy).
4. Reduced light (if dust layer is not too thick) could reduce
mid-summer stress on leaves and fruit (reduce
fruit sunburn). Surround does that for growers that use it (but
see the next item for possible downside).
5. Increase steps to clean up fruit at harvest (dusty fruit has less
appeal to consumers, hard to remove from
stem end bowl and calyx bowl).
6. Harvest of dust-laden fruit from dust-laden trees is extremely
unpleasant (dirty work) and may have
health implications for the pickers. You cannot just go in and
wash it off with a water spray via airblast
sprayer -- you end up with muddy blotches that are an even
greater problem to remove after picking.
You can go in with just the airblast sprayer alone, but you
likely will just re-distribute the dust within
the orchard. If you go the airblast sprayer alone route, I'd
suggest picking a nice windy day, shutting
off one side of the air blast (direct the wind output one way)
if possible, start at the upwind side and
work your way across the orchard always directing the output
downwind (and, eventually, at the last
row, out of the orchard altogether with the aid of the weather
supplied wind). It likely won't remove
all the dust, but it might help reduce it to the point where one
could live with it in a severe situation.
7. Interference with pollination if dust deposition occurs during
bloom and pollination. We saw this here
in a couple of dust-impacted orchards. It was pretty obvious
when fruit set was extremely low in
orchard rows adjacent to the road, increasing to levels requiring
thinning by three to four rows into
the orchard. There was no frost gradient in those orchards, so
it wasn't weather related.
Bill mentions increased impact on bacterial disease. We have not seen
that here in Colorado -- too dry. But it could be a consideration in
areas receiving more precipitation during the growing season than we do
here.
One other situation we saw here occurred when the gravel Co. put down
magnesium chloride to control dust on the haul road. The red Delicious
apples closest to the road received a greater deposition of dust despite
the treatment and those trees developed symptoms resembling salt injury
with severity decreasing with distance from the haul road. While I
cannot say for certain that it actually was salt injury and that it was
point of fact caused by the MagCl application and subsequent being
carried into the orchard, it certainly looked suggestive.
I cannot speak to the hydrology aspects, but they probably should also
be looked at. In cases with soil drainage problems, the gravel
operation might actually be beneficial in helping alleviate those wet
soils. In cases with high gravel soils, it could possibly be the
reverse (but I'm speculating here).
My suggestions to growers here: Try to influence the decision makers to
put the following rules in place.
1. Try to have the haul road paved (or look at other ways to reduce
dust generation by the haul trucks)
2. Require use of sprinklers to control dust within the operation
boundaries (on a frequent basis, not just
now and then!).
3. Protect orchard from dust deposition as much as possible. Optimal
would be to restrict gravel
mining operations to winter periods (almost no impact on flowers,
leaves, fruit). Minimum would be
to at least protect flowers from excessive dust during bloom and
pollination.
4. Document, Document, Document! Be sure you document your annual
fruit production of rows / trees
along a potential haul road / edge of property abutting the
operation. Do this by row / or tree on a
transect across potential gradients that might be generated. It
would be best to have such data for
several years if at all possible in case it is needed for a claim
or lawsuit for damages. The agencies
responsible for granting approval of gravel operations should be
asked to help make sure your
pre-existing agricultural land use is not injured without recourse
by the new operation.
There may be other impacts or aspects that I haven't thought, but these
may be helpful (I hope). Bottom line -- gravel pit operations adjacent
to orchards can make for poor neighbors to the orchardist.
Harold L.
--
Dr. Harold Larsen, Interim Manager - WCRC
Res. Pathologist & Ext. Fruit Dis. Specialist
Colo. St. Univ., WCRC - Orchard Mesa
3168 B 1/2 Road
Grand Junction, CO 81503-9621
Ph: (970) 434-3264, x-205
FAX: (970) 434-1035
EMail: [EMAIL PROTECTED]
Bill Shane wrote:
Kevin,
I would be equally concerned about the inevitable wind-blown dust and its
effect on bacterial disease, dislike of u-pick customers for sand storms.
The company may have a written plan for controlling dust (sprinkling with
water, etc), but this often is an idealistic idea rather than a reality.
Gravel operations are often required to erect berms and evergreen tree
barriers for privacy and sand drift abatement. This can play havoc with
natural air drainage channels.
These operations sometime reveal more extensive mining plans once they get
started. Counties and townships have been known to agree to proposals
before the implications to adjoining property are understood.
We have had bad experiences with gravel/sand mining operations here in SW
Michigan for the above reasons. A lot of suits have been brought against
mining operations as you can see:
http://www.aggman.com/news/news2004.htm
Bill Shane
-----Original Message-----
From: apple-crop@virtualorchard.net [mailto:[EMAIL PROTECTED]
On Behalf Of Kevin A. Iungerman
Sent: Thursday, July 05, 2007 11:12 AM
To: apple-crop@virtualorchard.net; [EMAIL PROTECTED]
Subject: Apple-Crop: Gravel mining impacts on bordering orchard?
Hello everyone.
I was contacted by a friend with a small orchard near Buffalo, MN who
has learned that a new property owner plans to surface mine gravel on
land adjacent to, and upslope of his small orchard. Eventually, the
property owner intends to sub-divide the land after the gravel is
removed.
As the neighbor's intent suggests, the orchard itself is a
considerably gravelly-loam soil, although, as happens on the prairie,
there is a small wetland and small lake to the other side of the
orchard, so obviously, some underlying areas have either good clay
content and compacted layers (or less likely, stone ledge).
I was asked, but did not know what the hydrological impacts might be
upon the orchard (if any) - save surface water run-off when soils are
either frozen or at field capacity.
For my friend's benefit, and also my own elucidation -- and possibly,
to similar gain for others out there -- I am interested in learning
of possible negative ramifications of such a venture, from persons
with similar circumstance or with particular knowledge in this regard.
Thanks much.
Best Regards, Kevin Iungerman.
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