Dane said:
Here is that info about blossom end rot and abscisic acid. You may not be able to get the whole section but just reading the abstract you will get the gist.
Wow, interesting. It's almost like that's contrary to everything that we've ever been taught... It's almost like somebody is making money off of all of the mined resources that we pump into/onto our plants.
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Undoubtedly, there are a lot of people who will be dismissive of this, because "we've always done it that way". But as correlation does not imply causation, it is interesting to note that several studies have indicated that the BER is often just a "phase" that the plant is going through, and would snap out of it, with or without the addition of calcium. But the addition of calcium coincides with the end of the BER (which would have happened, anyway), thus leading to the (false) conclusion that it's been cured by addition of said product.
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I have noticed that several studies on foliar feeding, are based off of research that was done in the early 50's, by a guy named Tukey, I believe. Basically, in his research, he sprayed plants with radioactive water, and observed the uptake. His research found that plants do, indeed, take in nutrients through every part, and the above ground parts take up nutrients at the rate of about .3 m/h. HOWEVER... this was also an early foray into the subject. Later scholarly efforts (such as the one referenced by juanitos) conclude that not ALL nutrients are able to be absorbed by the plant through foliage. And yet again, there are many places that continue, as an accepted agricultural practice, to foliar spray the lesser mobile (and allegedly non-absorptive) nutrients by foliar. So, it is quite the academic shitshow.
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It would be interesting to know if calcium is foliar applied in ignorance, or based on some other (yet again) legitimate evidence. Certainly, there is a legitimate use for foliar spraying. Particularly, in certain types of agriculture, fertigation is carried out at the upper end of practical levels - even to the point that lockout levels in soil are achieved. To bypass this, foliar spraying is an option. But it is wasteful, since application rates are higher, due to the inherent inefficiency.
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Anyway, thanks for posting that. Knowledge is power.