Question
Previous questions related to overall yellowing of grass.  I got my soil analysis back:
pH - 6.7  !!!  (Solid clay-I can't believe it.)
Phosphorus - 5 lb/acre
Potassium - 78 lb/acre
Calcium - 1130 lb/acre
Magnesium - 98 lb/acre
Zinc - 1.3 lb/acre
Manganese - 39 lb/acre
Copper - 1.8 lb/acre
Boron - .3 lb/acre
Sodium - 22 lb/acre
CEC (Cation Exchange Capacity 4.6 meq/100g
Acidity - 1.2 meq/100g
Base Saturation:Ca:61%;Mg:9%;K:2%;Na:1%;Total:73%

To be honest, what little I understand about this, the results are nothing like what I expected.  The ph is not low, and the Mg BS is right on target.  The recommendation was for 6 lb/1000 sq ft of triple supershosphate (0-46-0).  What do you think?

Answer
Well, that makes absolutely perfect sense.  But you have to be VERY careful with superphosphate, Ca(H2PO4)2.  This stuff will kill your grass if you put too much on.  I personally love it, even though I'm not supposed to - it's not organic, Superphosphate, but it yields very quick recovery for certain problems, like the difference between medicating with an IV and taking a pill.  A good organic source of Phosphorous would be Humus.  Phosphorous deficiency is a green light for broadleaf weeds and weedy grasses, and would k-o most cool season grasses; Zoysia may be tougher, but growing it in great soil with no interference means it can be at its greenest with no additional applications of Nitrogen.

Superphosphate builds roots to support the grass blades you put on steroids recently with your dose of high Nitrogen fertilizer.  Your Triple Superphosphate 0-46-0 is actually 14% Calcium.  Adding this will boost the middle number in the N-P-K description on fertilizer packages.  Just what the doctor ordered.

The Cation Exchange Capacity, CEC, is not something you can change overnight.  But I think this is an interesting number.  CEC measures the amount of clay and humus. Both of these raise the quality of nutrient- and water-holding potential in your soil.  Soils high in sand, with low levels of organic matter, test very low CEC; minerals are scarcely available and not retained, so plants have a hard time growing in them.  Heavy clay soil that contains substantial amounts of organic matter also holds a bigger capacity for holding cations.  

Soil with low CEC contains too little clay and humus for the typical gardener's needs. This is the kind of soil that is begging for some good organic conditioning.  CEC can be used to determine Nitrogen and Potassium applications.  Low CEC soil tends to leach.

Clay tends to test high for CEC, but Different kinds of clay test differently.  Kaolinite Clay tests in your range with 3 to 15 meq/100g.  

The numbers are in, your pH is good (surprise surprise), and the only thing you really have to worry about now is your grass.  I think you have some work to do.  What have you learned from this experience?  What would you do differently if today was May 1, 2006?