North American Fruit Explorers mailing list at ibiblio

[Lucky Pittman <lucky.pittman@murraystate.edu>]

At 03:27 PM 8/10/2006, Donna wrote:
> We have a botany fanatic here that I like to talk with, when I said that all
> the pecans we'd planted in our bad clay soil had died , he pointed out that
> they need zinc.  It was another of those forehead slapping realizations, oh
> of course!  If any plant has a high need for any particular element, you can
> be sure that we will need to add it.  Okay, boron to make the apples grow,
> zinc to make the pecans grow, anything else we need to know?

Hopefully Topgun will weigh in here on this one - he's probably got 
more experience than anyone on the list, so far as Zn and pecans are concerned.
I've seen some published papers sometime in the last year or two 
addressing the effects of cultivation and types of groundcovers, 
etc., with regard to Zn levels and Zn availability for pecans.  In 
native pecan groves, Zn deficiency is typically not a major problem, 
as Zn is constantly recycled by the annual drop and decomposition of 
leaves, twigs, etc.  But, if the soil in the orchard is cultivated, 
with diminution of vegetative ground cover and litter, much of the Zn 
leaches away; additionally, conversion of the natives to selected, 
higher-producing cultivars also dramatically increases the need for zinc.
Granted, commercial pecan production generally relies upon 2-4 foliar 
feedings of Zn at appropriate times during the growing season, but 
before Man's intervention, the native pecans cycled Zn through the 
roots - however, productivity was a fraction of what we want & demand.
It *may* be that some 'strains' of pecan could be more effective at 
taking up Zn from the soil - but all the evidence I've seen to that 
end, thus far, has been strictly anecdotal.

Now then, what about hickories grafted onto pecan rootstock?
What role does Zn play in that situation?
I don't have a clue.

Lucky