"Potassium (K) activates the manufacture and movement of sugars and starches, as well as growth by cell division. Potassium increases chlorophyll in foliage and helps regulate stomata openings so plants make better use of light and air. Potassium encourages strong root growth, water uptake and triggers enzymes that fight disease. Potassium is necessary during all stages of growth. It is especially important in the development of fruit."....AND..
" Potassium (K) is required for healthy leaves, flowers anf fruit, also making plants winter hardy and improving disease resistance. It is taken up by the plant as soluble K+ ions. The amount of N that is present in relation to K has an important effect on balanced growth. The ideal N:K ratio is 1:1 for most crops and 2:3 for root crops and legumes. Leafy crops take up large amounts of K if they are fed extra N. Grasses take in more K than they need and if the cuttings are continually removed this leads to depletion of the reserves of K in the soil. Where there is a deficiency the plants grow slowly with a greater risk of disease and some plants may show bronzing of the foliage.
Chemical weathering of rocks and soil frees K+ ions which are usually adsorbed by soil particles, but they can be leached from sandy soils which are low in organic matter. Magnesium (Mg++) ions compete with K+ for uptake, but if the K:Mg ratio is about 3:1 or 4:1 there is no problem.
Artificially K it is applied as:-
* Potassium Nitrate (K2NO3) - the advantage of this compound is that it provides N as well. Most K salts are very soluble and Potassium Nitrate is hygroscopic which means that it draws moisture from the air so left on its own it becomes liquid, so it is best used in a resin coated, slow-release formulation.
* Potassium Oxide (K2O) Potassium Magnesium Sulphate ( or Sulphate of Potash Magnesia K2SO4) and Potassium Chloride (or Muriate of Potash KCl ) are other salts that are used. The Chloride ions can build up upsetting the osmotic balance and some crops such as potatoes are sensitive to Chloride ions.
* An Organic source is ash from burnt green wood and foliage which contains 5-15% K and adding organic matter improves the holding capacity for K+ in sandy soils."
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they are growing slow with the leaves curling underneath,
...the first thing that comes to mind, is 'over watering'.
though I agree, there are far better, less toxic sources of nitrogen, phophates and potasium (manures, guanos, alfalfa, fish,wood ash, compost, seaweed, kelp, feathermeal.ect) , I doubt any "require the death of a mammal". Those products are
by-products of the slaughter process. Untill the majority of the population ceases to indudge Micky D's, Burger King, Out back, Hardees, Jack-in-the-Box, Oscar Myer, ect,. ect. there wil be plenty of by-product without killing for the purpose of fertilizers.
