Sulfat och PMDD

[BluesBoy]

Skrev ett inlägg på min blogg ikväll och jag kunde inte låta bli att fortsätta fundera lite på varför jag får det att fungera bättre när jag doserar K2SO4 och MgSO4. Jag har alltid blundat för Sulfat men börjar nu snegla lite snett?!? Mitt brunnsvatten innehåller ej mätbara nivåer (< 2 mg/l) SO4 och hur jag än vrider och vänder på det så får jag inte ner något S i burken med enbart NPK-/Mikrogödningarna.
Ok, S kanske inte går åt så mycket men nått borde man väl erbjuda grönsakerna? Normalt komunalt vatten brukar väl innehålla en del som säkert räcker och blir över men i mitt fall?
Vad tror ni - skulle det endast resultera i brister eller påverkar det fotosyntesen markant också?

[defdac]

Från en barrreport Mars 2006 som handlar om sulfat:

"Generalized ratios for S in plant biomass are as follows:
P:S = 2:1
N:S = 15-17:1

It is important to note that plants can and do store sulfate in large amounts in their vacuoles. Limiting the water column may not reflect a plant limitation over short time frames. It is therefore suggested to limit most nutrients at high growth rates for a 21-30 day time frame to deplete any reserves. Many aquarist make the error of assuming the water column reflects directly the status of the plant at that same time. This is seldom an issue with sulfate, but when approaching limitation studies, this certainly needs addressed well before making conclusions.
Assimilation and uptake occurs primarily in the leaves in plants. In some cases, adding K2SO4 appears to improve plant growth even though K+ is non limiting, this is rare, but maybe due in part to the SO4. Like PO4, not much is required for plant nutrition and demand.
As N and P play central roles, so does S, thus its uptake and assimilation is intimately linked to other nutrients that can cause co limitations that may appear similar to N deficiencies."

[BluesBoy]

Thanks!
Assimilation and uptake occurs primarily in the leaves in plants. In some cases, adding K2SO4 appears to improve plant growth even though K+ is non limiting, this is rare, but maybe due in part to the SO4.
Har man inget S alls som hos mig låter det som mina misstankar kan stämma till viss del.

As N and P play central roles, so does S, thus its uptake and assimilation is intimately linked to other nutrients that can cause co limitations that may appear similar to N deficiencies.
Häftigt. Bara att fortsätta med K2SO4 alltså.