On Fri, 7 Mar 2003 21:37:25 +0000 (UTC), (Victor
M. Martinez) wrote:
Joe Doe wrote:
precipitate. If you do suceed in moving the pH to neutrality with sulfur
more phosphate becomes available but it is unlikely to ever really

You can't really change the pH of our soils to neutral for long.

I had a series of soil tests done on my yard when I first bought my
home. The results showed I had 9,000 pounds of "excess" calcium per
acre in the top 6 inches. To convert the excess calcium to calcium
sulphate or calcium phosphate would take roughly the same weight of
sulphur or phosphorus. And that is just for the top six inches.

LCRA completed a study several years ago looking at the subsurface
migration of phosporus from a septic tank leach field. It did not
occur due to the reaction with calcium - the phosphorus was
precipitated immediately and was no longer soluable.

What is a problem here and Victoria has something posted about it here
is the weed and feed products. There was an ad in the paper the other
day which included 7 different lawn fertilizer products. Only one of
these did not have herbicides in it. Some of the bags had big
Atrazine labels. Every bag, however, was label "Put the contents of
this bag on 5,000 square feet (or so)". No mention of weight of
contents of the bag. State law makes them put the numbers on the bags
for N-P-K content since it is a fertilizer, an agricultural product.

Soil nutrient chemistry is a lot more interesting and fun that that.

Rusty (on a soapbox) Mase