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[APD] RE:K+ at high or low Ca values (Steve Pushak):



>
> Could Antonio Trmas' apparent problem with Ca uptake be caused by too high
a
> level of magnesium?
>
> Terrestrial plants have problems with Ca deficiency with high K (saline)
> conditions because the high salt level interferes with the transpiration
> stream by making it difficult for the plant to take up and respire water.
> There has to be a sufficient transpiration stream to conduct this mineral
> because it is not easily transported. Aquatic plants would not have this
> problem because the Ca is present in solution & does not rely upon
> transpiration.
>
> The mechanism for magnesium toxicity is different. Doesn't this mineral
> interfere by substituting for Ca chemically?
>
> Just a wild guess, but perhaps lowering the K level in the water can
induce
> enough transpiration to bring Ca from substrate interstitial water into
his
> Echinodorus to ameliorate the shortage?
>
> We don't really know if the Ca levels in his water are sufficient since
the
> high GH levels might be disproportionately due to Mg. The Ca in the water
> might be being used up.
>
> Peat & organic material can absorb a great deal of calcium from solution
by
> exchanging lower affinity cations such as sodium & potassium.
>
> I induced salt stress (leaf loss, red coloration) in my cherry trees a
> couple years back when I fertilized with lime. My theory was that the lime
> liberated enough salts by cation exchange from the manure-rich soil to
> create a salinity problem.
>
> Steve P


I live on Mallorca Island, and is "made" with lime, my tap water is very
rich on Ca. I dose my nutrients by "spoons" and sometime my eye is not well
calibrated and I have this trouble (distorted grow). The simptoms reverse
very fast if the K dose is stoped. I really do not know my Ca, Mg or K
level, only my GH is about 15, and there is a lot of Ca for sure

Regards
Antonio Trías.
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