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Wild Flora wrote:
>>From "White Clover (Trifolium repens) Control and Flower Head Suppression
>in Apple Orchards" by Andrew W. MacRae, Wayne E. Mitchen. David W. Monks,
>and Michael L. Parker, Weed Technology, Volume 19, Issue 2, May 2005:
>
>"White clover is a weed in apple orchards that competes with the crop; also,
>flowers of this weed are unwanted attractants of honey bees at times when
>insecticides, which are harmful to these pollinators, are being applied."
>
Hi Flora & All, June 27, 2007
I tend by reflex to think in terms that relate to local conditions
(e.g. evapotranspiration of ~ 1"/week during the growing season,
moderate rainfall during the growing season sufficient for maximum
production in soils with 6" available water holding capacity in the
rooting zone (100 cm tension minus 15 bar expressed on undisturbed core
basis), significant leaching of nutrients from bare earth during the wet
shoulders and winter, significant hazard of soil erosion from extensive
bare earth year round, hazard of frost heave/tree lean when there is
bare earth within the drip line over winter, significant tendency for
rutting of bare earth during spraying, pruning and harvest operations)
that, excepting atypical soil conditions, requires mowed sod in the
alleys and mulch and/or only partial (i.e. temporary) or restrained weed
control in the tree row. So in this local context, sod cover of clover
or various grass species (whatever from the initial seeding manages to
survive and dominate in the various zones) enables soil conservation and
orchard management. Assuming reasonable fertile conditions initially,
then a pep pill of nitrogen as grass starts to green of about 20 lb
N/acre (2 grams/m^2) and a light spray of herbicide along the tree row
(or mulch) to give new apple roots a temporary advantage, helps to
avoid irregular bearing by favoring better fruit set.
One orchard trial that I planted in 1974 on the above principles (&
1/4 square bale of hay/ tree each year) was still going strong 21 years
later when I retired; no mineral supplements during this period other
than N. You may notice shades of 'organic farming' in a system that
required no limestone, minor elements (perhaps some B), P, Mg or K over
a 21 year period.
I would conclude from the quoted statement that MacRae et al. write
from the viewpoint of an area with less total rainfall, less potential
for leaching, frost heave and erosion by wind and water; or perhaps with
less insight. One of the UK stations (East Malling ?) was pushing
entirely bare earth for orchards about 25 years ago. I would have
expected some degradation in biopores there by now but their 'bare
earth' in practice may be less than fully bare.
>
>Do you have a source for the statement that "the foundation of organic
>farming is largely nonorganic"?
>
Yes & no. Note that the full statement was----
"With the exception of some favorable
alluvial, loess and dykeland soils, the foundation of organic farming is
largely nonorganic, i.e. enabled by previous or current fertilizer use
within the watershed (dust shed, reach of birds, pollen, seeds, insects
and other vectors of nutrient dispersal) and this foundation will be
subject to gradual depletion."
My primary source is DHW, this being a distillation of everything I have learned about nutrient management and practical agriculture, and not yet forgotten, with focus directed to the long-term practicability of organic farming dogma with respect to soil fertility, so in that respect I do have a source. Can I direct you to some publication in which this view is directly expressed ? No.
DIGRESSION:
But I can refer to a viewpoint that bears on the dynamics of developments like organic farming; In the Republic of Plato, Socrates observes that "...to do anything in excess seldom fails to provoke a violent reaction to the opposite extreme..."
Using the above observation as a model, one can view the current swing to organic farming as an extreme reaction to the previous extreme and equally illogical view that for every problem there can be a simple quick chemical fix that is free of undesirable side-effects. And using this same model one can suppose that these two extreme positions lie at opposite ends of a much large continuum, in which the less extreme manifestations of two merge and are indistinguishable.
The large number, by far the majority, who fall somewhere in this middle ground make specific choices because they feel they fit their circumstances, not because they fit or don't fit organic criteria. But some of their choices may approximate choices mandated by organic dogma; shades of grey as opposed to black and white.
In the late 1960s I noticed that many growers were using herbicide to excess in orchards, developed the concept of partial (temporary) weed control for the tree row and advocated this at every opportunity. Being introduced at a grower's weed control meeting, by the Provincial Weed Specialist of the day, as 'the guy who is afraid of herbicides' helped establish the view that if some herbicide is good then less may be better; not pure organic but not pure nonorganic either.
Back in the pre-herbicide days (1940s is the time I remember; $0.25/hr & 60 hr weeks for the paid crew & eggs were $0.75/ dozen) we never did manage to keep up with the weeds with the result that the accumulated seed bank was enormous.
I suspect that profitable production of row crops without herbicides is in many cases now possible only because prior decades of good weed control with herbicides have depleted the seed bank.
END OF DIGRESSION
Getting back to foundations-- In a region where it may rain at the wrong time and often does (e.g. seeding; cultivation; harvest) the better agricultural soils for row and high value crops are the lighter better drained soils; not because they are more fertile and hold nutrients well but because they let water through more rapidly. But because they drain rapidly these soils are often low in fertility even when broken and tend to lose nutrients to leaching.
In theory one could, with deep pockets and unlimited patience, build these soils up using hay from rich natural unfertilized meadows. And by converting this hay to manure and bedding one could, using catch crops in addition, build such soils up to enable 'organic' production.
But is one really supposed to believe that this hay from a natural 'unfertilized' meadow is free of chemical fertilizers ? Being a natural meadow it is flooded nearly every year or more frequently. Other things being equal, nutrients in either adsorbed or dissolved form will move at greater flux as nutrient concentration in the soil increases. If say 20% of watershed flow is from fertilized farmland or fertilized lawns/gardens then you may be sure that more than 20% of nutrient flux to the meadow is from these fertilized areas.
When snow-free bare ground combines with cold windy weather there will often be mini dust storms if windbreaks are too far apart. This dust is the fine soil fraction and in a fertilized (or fertile) soil will be rich in nutrients. If there is a mosaic of nutrient-poor areas among the rich then you may be sure that more nutrients will move from rich to poor than from poor to rich. These tainted dust storms may land on a field even if the sign says 'this field is certified pure organic'.
The same reasoning applies to movement of any bodies that may contain nutrients from fertilized fields to organic fields (pollen, seeds, flying insects, birds, livestock, deer...).
Before the development of mined or artificial mineral fertilizers many upland soils became depleted after a generation or so and maintaining fertility was a constant struggle; written mostly in famine and war. But when mineral fertilizers are applied in company with practices that build up organic matter then a level of fertility is reached that can sustain fertilizer-free production for decades if you don't mind mining (or undermining) soil fertility.
I have not seen organic certification standards for some time and recall only a few, and those vaguely, but I think a field must have had no mineral fertilizers applied in the previous 5 years. If the field has e.g. a 60 year history of fertility enhancement by use of mineral fertilizers then 5 years will not even make a dent. Pretending that fertilizer-free production on such a field is due to some kind of organic magic is like buying a lifetime supply of gasoline and pretending that your car uses free gas.
This is much longer than I intended at first but one thought leads to another.
Yt, Dave Webster, Kentville
>
>WF
>
>-----Original Message-----
>From: naturens-owner@chebucto.ns.ca [mailto:naturens-owner@chebucto.ns.ca]
>On Behalf Of David & Alison Webster
>Sent: Sunday, June 24, 2007 8:46 PM
>To: naturens@chebucto.ns.ca
>Subject: Re: [NatureNS] bees and industrial white clover
>
>
>
>Wild Flora wrote:
>
>>The only harm to bees that I'm aware of is when flowering clover attracts
>>them to an area where pesticides are going to be used. This is a recognized
>>problem in nonorganic apple orchards, where white clover is often regarded
>>as a weed.
>>
>Hi Flora & All, June 24, 2007
> I worked for about 29 years in orchard soil management, including
>orchard ground cover management, and don't recall hearing the notion of
>White Clover being regarded as a weed.
>
> This is now all very long ago and far away but, I am sure that White
>Clover was an ingredient of one if not two of the two seed mixes that we
>(I) recommended for use when establishing sod in orchards.
>
> On a matter related to organic farming, it is widely accepted that
>heat energy flows, other things being equal, from warmer to cooler
>bodies [e.g. with density very unequal, heat can flow from the colder
>body to the hotter, i.e. one would freeze instantly in some outer layers
>of the upper atmosphere that have very high temperatures but widely
>spaced molecules].
>
> It is equally true, but less widely recognized, that nutrients tend
>to flow from more fertile to less fertile soils (again with the other
>things being equal condition). With the exception of some favourable
>alluvial, loess and dykeland soils, the foundation of organic farming is
>largely nonorganic, i.e. enabled by previous or current fertilizer use
>within the watershed (dust shed, reach of birds, pollen, seeds, insects
>and other vectors of nutrient dispersal) and this foundation will be
>subject to gradual depletion.
>
> Hopefully some of the fad setters will wake up before we regress to
>the good old days of recurrent famine and 'Ein ta saw, ein ta gnaw and
>ein ta gie tha laird withaw'.
>Yours truly, Dave Webster, Kentville
>
>
>
>
>
>
>
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