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c-ray
12-22-2011, 08:47 AM
from http://www.unitedstatesag.org/cations.html

Potassium

It makes up only 2-3% of the CEC, but potash is the #1 dry fertilizer sold to AMERICAN farmers! Why?? Has the American farmers been sold excessive K?

Yes, and in a form undesirable to our soil. Who has made the rules of manditory nutrient required to produce 150bu corn, 45bu soybeans, 60 wheat, etc.?

Guidelines and recommendations come from the National Fertilizer Institute, thru Landgrant Universities, Cooperating Co-ops, etc.
The experts, who tell us, our crops require "specific" poundage of NPK forgot to tell us there are other sources, than to purchase NPK from the local fertilizer dealer.

EXAMPLE: To raise 150bu corn (grain) it removes 135# N, 53# P, 40# K. They forgot to tell us that our healthy silt loam soil can have a K reserve of over 35.000# (300 to 400 available K in balance soil). Plus earthworms can add K to your soil fast, earthworm castings have 11 times more K than soil particles and organic residues that run through them. WHAT A WASTE OF MONEY TO BUY UN-NEEDED 0-0-60. K is a necessary nutrient which aids in photosynthesis, protein formations. and size n' quality of fruit. K is very important (20,000 to 35.000# per acre.)

The #1 potash product is potassium chloride (KCL) or muriate of potash. Muriate of potash can be red or white. Most kalium is white muriate of potash. Muriate is a salt of hydrochloric acid. Farmers on natural-organic programs should never use killers of "soil life". Chemically K reacts in soil to release sodium (salt). High usage of KCL adds too much NA, which prunes plant roots and will not allow water and nutrients to flow freely to the plants. BEWARE it is approximately 47% chlorine and it can become a KILLER TO SOIL LIFE, animals and people. It is quickly leached from the soil, or is locked up in fixed non-exchangeable K with less than 20% actually used by the crops in many soil conditions.

MURIATE OF POTASH 0-0-60 K,20 is actually only (approx.) 51.7 % K and 47% Chlorine. Chlorine is a gas that kill life! Research indicates Chlorine is a wild cat element and is seldom broken down, but continues to be tax to the soil and water.

LET'S LOOK AT CHLORINE - KCL or Potassium chloride, or more commonly called muriate of potash is 47% chlorine. Therefore, a 100# (actual K) application will add 42 to 45 ppm of chlorine to your soil, which is about 12 times the chlorine it takes to sterilize water!


Potassium acts like Sodium

K acts like Na (two true acids). They are fast acting, and there is no need of trying to build a reserve of K through commercial fertilizers. It will brake you financially, so don't play their game of recommended soil nutrient levels, you can't win at their game, so do it NATURE'S WAY. Some closing thoughts on potassium:

A very small percentage of broadcast applied K will become exchangable during the growing season, or even show up on a soil test. WHY?? Most commercial K is 100% water soluable on soil contact; therefore making it is highly leachable (up to 75%) on sandy soil and most of the remaining K is fixed in the soil due to unbalanced conditions (even the CI makes K unavailable). Most commercial K is broadcast applied in early spring and can move out of the soil quickly with springs rains.
SAD TO SAY - A plants' need for K starts out in small amounts in a young growing plant. In corn, less than 5% of total K needed, is used from germination to approximately 38 days after emergence (when tassel begins to develop).
Most of the K that a plant will use is obtained by diffusion. That means the magnetic pull of the root draws the K to itself as needed (K must be within % " of the root to be exchangeable). This is why direct seed placement and foliar sprays can be very profitable at very low rates. Well floculated, aerated soil has a much higher uptake of K by roots. Adequate moisture is required for K movement.

c-ray
09-02-2012, 06:01 PM
http://www.sciencedirect.com/science/article/pii/S0926669012002610

Abstract

Potassium response trials were conducted on hemp on four sites with different levels of soil potassium in 2011 in which the main factor was variety and the second factor was potassium rate. Five rates of applied potassium were used (0, 60, 90, 120, and 150 kg K/ha). There was no significant relationship between hemp yield and either potassium rate or the level of soil potassium. Potassium uptake from the site with the lowest level of soil potassium was significantly lower (65 kg K/ha) compared to a site with a higher level of soil potassium (83 kg K/ha) suggesting that hemp will take up potassium when the element is not needed. Most of the absorbed potassium was concentrated in the stem (70–75%), harvest off-takes for most applications would consist of only stem and any potassium in root and leaves would remain in the field. The results of this limited investigation suggest that hemp has a lower requirement for potassium than other crops and that the optimal potassium fertilization strategy for soils with moderate to high levels of potassium (>70 mg/L; Morgan's test) is to replace off-takes after the hemp has been harvested. Further research is necessary to develop robust potassium fertilization guidelines for hemp.

Highlights

► The potassium requirements of hemp crops are low.
► Hemp will take up more K than needed if excess quantities of K are available.
► Late maturing varieties will take up more K than earlier maturing varieties.
► Replacing K post harvest may be the optimal strategy on soils with higher levels of K.