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Thread: K, N and plant growth

  1. #1
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    K, N and plant growth

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    Just to share some thots, research and experience, and also to get feedback from other's experience/knowledge.

    I've recently taken to dosing my N-limited planted tank with KNO3. The noticable difference, was the plants grew slower... but bushier. It seems that they stopped rushing to reach the surface and grow sideways instead. I guessing its due to the fact that when there's a lack of N in the water and substrate, the next source is air where they can get atmospheric Nitrogen. I've ruled out inhibition of growth by excess N as I only raise my NO3 to 5ppm. In addition, when I was dosing 1ppm per night, the NO3 remained at zero, implying the NO3 was being used. It only started rising when the dosage was raised to 2ppm per night. (Note also, with reference to the following paragraphs, that in addition, KNO3 also dosed K by ~0.8ppm per 1ppm of NO3.)

    I've also started dosing my tanks with K2SO4 every week to raise K by 20ppm. Same results... plants stopped rushing for the surface and plants like Hygrophila started putting out horizontal stems at mid-tank rather then at the surface. From what I've read, K plays a key role in many functions of a plant, including photosynthesis, absorption and transportation of nutrients, manufacturing of food (sugars, etc) and enzymes, and cell wall structures. One important point for me was that K makes photosynthesis and food production more efficient and I'm speculating that's the reason my plants stopped rushing for the surface, i.e. light. (One farming article stated that K is also known as the quality nutrient due to its positive effect on attributes of crops like size, shape, colour, taste, shelf life, fibre quality and quality factors)

    So far, experienced aquarists have not noticed algae problems associated with excess K, but it can limit the uptake of Magnesium which in turns effects the utilisation of Iron. Unfortunately, there isn't a easy way to test for K. The only indicators are (to my knowledge) Iron defeciency symtoms when there is still iron in your water (excess K) and yellow spots/holes on your leaves (K deficiency). Recommended levels range from 20ppm or less up to 40ppm per week.

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    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
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  2. #2
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    K, N and plant growth

    Just to share some thots, research and experience, and also to get feedback from other's experience/knowledge.

    I've recently taken to dosing my N-limited planted tank with KNO3. The noticable difference, was the plants grew slower... but bushier. It seems that they stopped rushing to reach the surface and grow sideways instead. I guessing its due to the fact that when there's a lack of N in the water and substrate, the next source is air where they can get atmospheric Nitrogen. I've ruled out inhibition of growth by excess N as I only raise my NO3 to 5ppm. In addition, when I was dosing 1ppm per night, the NO3 remained at zero, implying the NO3 was being used. It only started rising when the dosage was raised to 2ppm per night. (Note also, with reference to the following paragraphs, that in addition, KNO3 also dosed K by ~0.8ppm per 1ppm of NO3.)

    I've also started dosing my tanks with K2SO4 every week to raise K by 20ppm. Same results... plants stopped rushing for the surface and plants like Hygrophila started putting out horizontal stems at mid-tank rather then at the surface. From what I've read, K plays a key role in many functions of a plant, including photosynthesis, absorption and transportation of nutrients, manufacturing of food (sugars, etc) and enzymes, and cell wall structures. One important point for me was that K makes photosynthesis and food production more efficient and I'm speculating that's the reason my plants stopped rushing for the surface, i.e. light. (One farming article stated that K is also known as the quality nutrient due to its positive effect on attributes of crops like size, shape, colour, taste, shelf life, fibre quality and quality factors)

    So far, experienced aquarists have not noticed algae problems associated with excess K, but it can limit the uptake of Magnesium which in turns effects the utilisation of Iron. Unfortunately, there isn't a easy way to test for K. The only indicators are (to my knowledge) Iron defeciency symtoms when there is still iron in your water (excess K) and yellow spots/holes on your leaves (K deficiency). Recommended levels range from 20ppm or less up to 40ppm per week.

    Comments?
    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
    Why use punctuation? See what a difference it makes:
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    A woman: without her, man is nothing.

  3. #3
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    K, N and plant growth

    Just to share some thots, research and experience, and also to get feedback from other's experience/knowledge.

    I've recently taken to dosing my N-limited planted tank with KNO3. The noticable difference, was the plants grew slower... but bushier. It seems that they stopped rushing to reach the surface and grow sideways instead. I guessing its due to the fact that when there's a lack of N in the water and substrate, the next source is air where they can get atmospheric Nitrogen. I've ruled out inhibition of growth by excess N as I only raise my NO3 to 5ppm. In addition, when I was dosing 1ppm per night, the NO3 remained at zero, implying the NO3 was being used. It only started rising when the dosage was raised to 2ppm per night. (Note also, with reference to the following paragraphs, that in addition, KNO3 also dosed K by ~0.8ppm per 1ppm of NO3.)

    I've also started dosing my tanks with K2SO4 every week to raise K by 20ppm. Same results... plants stopped rushing for the surface and plants like Hygrophila started putting out horizontal stems at mid-tank rather then at the surface. From what I've read, K plays a key role in many functions of a plant, including photosynthesis, absorption and transportation of nutrients, manufacturing of food (sugars, etc) and enzymes, and cell wall structures. One important point for me was that K makes photosynthesis and food production more efficient and I'm speculating that's the reason my plants stopped rushing for the surface, i.e. light. (One farming article stated that K is also known as the quality nutrient due to its positive effect on attributes of crops like size, shape, colour, taste, shelf life, fibre quality and quality factors)

    So far, experienced aquarists have not noticed algae problems associated with excess K, but it can limit the uptake of Magnesium which in turns effects the utilisation of Iron. Unfortunately, there isn't a easy way to test for K. The only indicators are (to my knowledge) Iron defeciency symtoms when there is still iron in your water (excess K) and yellow spots/holes on your leaves (K deficiency). Recommended levels range from 20ppm or less up to 40ppm per week.

    Comments?
    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
    Why use punctuation? See what a difference it makes:
    A woman, without her man, is nothing.
    A woman: without her, man is nothing.

  4. #4
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    K, N and plant growth

    Just to share some thots, research and experience, and also to get feedback from other's experience/knowledge.

    I've recently taken to dosing my N-limited planted tank with KNO3. The noticable difference, was the plants grew slower... but bushier. It seems that they stopped rushing to reach the surface and grow sideways instead. I guessing its due to the fact that when there's a lack of N in the water and substrate, the next source is air where they can get atmospheric Nitrogen. I've ruled out inhibition of growth by excess N as I only raise my NO3 to 5ppm. In addition, when I was dosing 1ppm per night, the NO3 remained at zero, implying the NO3 was being used. It only started rising when the dosage was raised to 2ppm per night. (Note also, with reference to the following paragraphs, that in addition, KNO3 also dosed K by ~0.8ppm per 1ppm of NO3.)

    I've also started dosing my tanks with K2SO4 every week to raise K by 20ppm. Same results... plants stopped rushing for the surface and plants like Hygrophila started putting out horizontal stems at mid-tank rather then at the surface. From what I've read, K plays a key role in many functions of a plant, including photosynthesis, absorption and transportation of nutrients, manufacturing of food (sugars, etc) and enzymes, and cell wall structures. One important point for me was that K makes photosynthesis and food production more efficient and I'm speculating that's the reason my plants stopped rushing for the surface, i.e. light. (One farming article stated that K is also known as the quality nutrient due to its positive effect on attributes of crops like size, shape, colour, taste, shelf life, fibre quality and quality factors)

    So far, experienced aquarists have not noticed algae problems associated with excess K, but it can limit the uptake of Magnesium which in turns effects the utilisation of Iron. Unfortunately, there isn't a easy way to test for K. The only indicators are (to my knowledge) Iron defeciency symtoms when there is still iron in your water (excess K) and yellow spots/holes on your leaves (K deficiency). Recommended levels range from 20ppm or less up to 40ppm per week.

    Comments?
    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
    Why use punctuation? See what a difference it makes:
    A woman, without her man, is nothing.
    A woman: without her, man is nothing.

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    Mmmmmm...interesting..[] ...those supplements are bought from where? Is it costly?
    Plant Physiology by Taiz and Zeiger

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    Hey Vinz, I dun mind trying your suggestions. Where to get the stuff you mentioned.

    Thanks.

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    plants cannot fix atmospheric nitrogen, they dun have the enzymes to do it.... only bacteria can do that.

    You may want to try adding phosphate to your tank also, though it is still very much a taboo (like nitrate many years ago)...

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    No phosphate for me... PO4 in my planted is way, way over the 2ppm limit of my test kit. I thought the excess might be due to N-limitation, so I added KNO3. Results = bloom of hair/thread algae and PO4 still over the test kit upper limit. *sigh* Anyway, the tank was tagged for a rescape which was finally done over the weekend.

    Thanks for the info on atmospheric N and plants. So in this case the extra K from the KNO3 could be the factor.... hmmm.
    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
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    A woman, without her man, is nothing.
    A woman: without her, man is nothing.

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    If you guys want to try this, try it with your eyes open. You can get more info by searching the APD archives, TheKrib, rec.plants.aquaria.plants newsgroup and seaching google or altavista for 'potassium' and 'plants', or various combos of relevant terms.

    K2S04 can be purchased from Dr Mallicks for $7.60 per 1kg bottle. See this thread for details.

    You can also get KNO3 from him, BUT excess NO3 can cause algae problems... so try at your own risk. Again more info can be had at the sites mentioned above.
    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
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    A woman, without her man, is nothing.
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    Hi All,

    Since we are in the topic of nutrient, thought I might as well ask. I was discussing about plants using NH4 for its N instead of NO2 and NO3 with KF. Plants seem to favour NH4 more than the NOs because of the energy they need to reduce them before they can actually use them.

    Would like to know if anyone out there fiddled with NH4NO3 or (NH4)2SO4?

    Geoffrey

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    NH4 is in equilibrium with NH3 which is poisonous to fishes. You could kill your fishes if you are not careful.

    NH4/NH3 is also reportedly prefered by algae and could cause GW.

    BC

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    I have played with played with NH4... but it does more harm than good overall (algae grow). and it does not push the growth any more than NO3. and, it is becomes toxic NH3 in alkaline pH... so the CO2 cannot off, KH cannot over do. A bit risky I would say.
    "Ecology of the planted aquarium" advocates the advantages of NH4, but I dun remember the author suggest adding them to the tank rite? nor high fish load to keep the NH4 among other nutrients high.

    Let me know if you need a bit of NH4NO3 solution to try.

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    ----------------
    On 9/30/2002 7:43:13 PM

    I have played with played with NH4... but it does more harm than good overall (algae grow). and it does not push the growth any more than NO3. and, it is becomes toxic NH3 in alkaline pH... so the CO2 cannot off, KH cannot over do. ----------------
    CK Yeo,

    What ppm have you tried? Read somewhere that 0.02ppm should do the job. I shall remember to ask when I need them but not right now. Thanks for your offer.

    Geoffrey

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    thanks for the sharing. these are good educational discussion for me.

    today i purchased potassium sulfats (K2SO4) and magnesium sulfats (MgSO4) from Dr. Mallick's store. however i was not able to reach him on his mobile. can someone advise me on the dosage? mine is a heavy planted 4x2x2 tank. how frequent and the amount that i should use for both?

    thanks in advance.

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    Wee,

    Go to Calculating dosages of fertilizer elements for a planted tank.

    IME, mix K2SO4 when you need it, cos you need lots of it, but only weekly. I have to mix 4.5 tsp with 250ml to dose my 6 foot once to raise 20ppm. MgSO4, you can mix up a bottle and keep.
    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
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    A woman, without her man, is nothing.
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    ----------------
    On 10/4/2002 7:38:37 PM

    Wee,

    Go to Calculating dosages of fertilizer elements for a planted tank.

    IME, mix K2SO4 when you need it, cos you need lots of it, but only weekly. I have to mix 4.5 tsp with 250ml to dose my 6 foot once to raise 20ppm. MgSO4, you can mix up a bottle and keep.
    ----------------
    thanks. i am not sure if i calculated correctly. looks like, for a 300liter tank, i need 2 teaspoons of K2SO4 and 3 teaspoons of MgSO4 weekly. make sense?

    is there test kit for these 2 nutrients?

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    Hi Vinz, dun mind me asking where is Dr mallicks?

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    Wee,

    Your calculations are right. No test kits for these 2. I wrote something about K guesstimation above.

    For Mg, you measure your gH. High gH is usually an indication of Mg and Ca in the water. I have no idea how the gH co-relates to Mg and Ca in terms of numbers. You can also look for Mg deficiency symptoms.
    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
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    A woman, without her man, is nothing.
    A woman: without her, man is nothing.

  19. #19
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    Samuel, search the AQ for Mallick... his contacts has been posted a few times.
    Vincent - AQ is for everyone, but not for 'u' and 'mi'.
    Why use punctuation? See what a difference it makes:
    A woman, without her man, is nothing.
    A woman: without her, man is nothing.

  20. #20
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    pro test kits exist for K but they're based on turbidity, which is very hard to quantify

    i just like to point one a few things
    with most planted tanks, nh3 poisoning isn't an issue due to the <7 pH
    also, i find adding K really helped flowering of emersed growth and SIZE of my floating plants
    as for N, i've never really bothered with it
    however, my bioplast liquid fert (nutriplant) contains N, P and K, so i couldn't say

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