Early K-lite results

[Stone]

¿Qué es lo que no entiendes?

And the point of writing something I can't read...... is?

 

[gonewild]

And the point of writing something I can't read...... is?

pointless!

 

[gonewild]

And the point of writing something I can't read...... is?

I asked what do you not understand.

 

[Stone]

Of course we do not know the proportions of elements picked up by the leaves and by the roots

Yes we do
http://journal.ashspublications.org/content/127/3/442.full.pdf

 

[Stone]

Here is the brom paper:
http://hortsci.ashspublications.org/content/43/1/146.full

 

[naoki]

Lance & Mike, it's ok to disagree, that's the part of science, right? Even though Lance doesn't seem to be interested in quantitative results, anecdotal/subjective evidence/observation can be a good start for science. Orchid culture is part science and part art, so it is good to have both sides.

Mike, I think that high-N diet (or low everything else) could be interesting. There are some variation among studies, but some studies show that benefits of K saturate quickly (i.e. as long as there is small amount, orchids seem to grow equally well). But higher N seems to contribute to more growths (even at 50-200ppm N). If that is the case, reducing one of the big 3 (K) is a good way to lower EC. Rick is probably calling this as preventing K accumulation, right? So the difference in the interpretation of K-lite success is the relative contribution of reduced EC vs the next step (interference by K).

Salt/osmotic tolerance is a big topic in plant biology. We know paphs are not good at dealing with high salt, but we don't know the quantitative effects on root growths (I failed to find any papers related to orchids). So does a bit lower EC translate to better growth? In one of Wang's older paper, his low and high fertilization treatments (4x higher concentration) resulted in twice as high EC at the media. He didn't seem to see much effects from this higher EC. But Phal tolerance is probably different from Paphs.

Bromeliad paper seems to be interesting. But the link to Brabantia's comment is not the right paper, is it? This is closer to her question (just abstract):
http://journal.ashspublications.org/content/138/3/229.short
but this is just for N. We don't know how much leaves can take up each of the other mineral nutrients.

 

[Stone]

But the link to Brabantia's comment is not the right paper, is it?

Table 7 shows NPK uptake

 

[Stone]

Lance & Mike, it's ok to disagree, that's the part of science, right? Even though Lance doesn't seem to be interested in quantitative results, anecdotal/subjective evidence/observation can be a good start for science. Orchid culture is part science and part art, so it is good to have both sides.

Yes if we all agreed on everything it would be like living on a clone planet.

If that is the case, reducing one of the big 3 (K) is a good way to lower EC. Rick is probably calling this as preventing K accumulation, right?

Well there realy is only the ''big 2'' N and K. therefore reducing K will quickly lead to increased N if you give the same EC. There is really nothing else you can reduce that would make such a difference. It's obvious that optimum nutrition is a balancing act between trying to provide optimum NPK and keeping salinity to just below growth reducing levels. Again this is something which is probably impossible to determine without trials in different media as well as differing N P K Ca Mg combinations. From all scientific data I have read having K at the same level as P is probably counter produtive in the long run and at the least completely unnecessery.

My point is if out of the ''big 2'', if you reduced N, the plant would not suffer from too much K - as Lance and Rick would say - it would suffer from too little N. Once you have optimum N concentration it seems that K can go as low as 15% of the N or as high as 150% without making much difference. That's why they call it ''luxury'' levels of K not ''destructive'' or ''inhibitive'' levels. (as long as EC remains with acceptible levels).

Sometimes during periods of short hours and dark weather (mid winter in the greenhouse for example), the extra K can be used by the plant to reduce etiolation caused by too much N along with low light. Although its really better to cut N than increase K too much in this case.

So the difference in the interpretation of K-lite success is the relative contribution of reduced EC vs the next step (interference by K).

Yes. There is no interference by K when given at reasonable levels. For orchids, a K to N ratio of 0.3-0.8 to 1 will work well and give you the option of increasing N and keeping EC the same by playing with the K and N.

Salt/osmotic tolerance is a big topic in plant biology. We know paphs are not good at dealing with high salt, but we don't know the quantitative effects on root growths (I failed to find any papers related to orchids). So does a bit lower EC translate to better growth? In one of Wang's older paper, his low and high fertilization treatments (4x higher concentration) resulted in twice as high EC at the media. He didn't seem to see much effects from this higher EC. But Phal tolerance is probably different from Paphs.

Correct. We may never know optimum EC for different paph spp. or any genus for that matter until each is trialed in it's own right. Something that wil never happen. But we can make an educated guess based on experience with different spp. It probably wouldn't be to difficult to use an expendible guinea pig and feed it higher and higher rates until you see root or other damage. But based on available data the higher N proposition seems to make more sense that the low K thing.