excess nutrients

[Jack middleton]

Hi all

I have heard this mentioned on a forum a few times and i wondered whether it is true as i don't think it is!

This person claims that excess potassium will restrict iron uptake, surely this defeats the whole point in EI?!

This person has an amazon sword with pin holes, potassium deficiency. so i recommended that they buy some potassium phosphate and dose a little every 2 days. And this person claims that the excess potassium would stop iron uptake.
What are your thoughts?

He also claimed that plants can only take certain nutrients through their leaves, such as silicates and chlorides etc, and that iron can only be taken through the roots, Im a bit dubious as to whether this is true as I have read numerous times that plants can easily take up nutrients through leaves and roots, regardless of the nutrient.

I think this may be one for clive.

Cheers, Jack

 

[aaronnorth]

This person has an amazon sword with pin holes, potassium deficiency. so i recommended that they buy some potassium phosphate and dose a little every 2 days. And this person claims that the excess potassium would stop iron uptake.
What are your thoughts?

this may help:

viewtopic.php?f=21&t=2950&p=31913&hilit=active+transport#p31913

KNO3 would be a better option as it contains more potassium than KH2PO4, or if they person doesnt want to add NO3 then suggest KH2SO4

This person claims that excess potassium will restrict iron uptake, surely this defeats the whole point in EI?!

EI is about non-limting nutrient levels, not dosing to excess, so the conecentration of each nutrient doesnt affect another unless it is unsuually high in the tap water.

i havent read about K+ restricting uptake of iron, but i have read that Mn, Zn and Cu will.

He also claimed that plants can only take certain nutrients through their leaves, such as silicates and chlorides etc, and that iron can only be taken through the roots, Im a bit dubious as to whether this is true as I have read numerous times that plants can easily take up nutrients through leaves and roots, regardless of the nutrient.

i dont think that is enitrely true, but rather plants prefer one uptake route over another, for example most plants prefer root uptake of PO4 over leaf uptake.
why i am not quite sure. probably something to do with the size/ mass or electrical charge of the atom

thanks, Aaron

 

[Jack middleton]

Cheers, Aaron, excellent reply!

Thanks

 

[ceg4048]

I have excess Potassium and I don't have any Fe uptake issues, so I wonder how that theory can explain my lack of difficulties. In any case if you've got holes in plants you should be looking at Carbon, not K.

Cheers,