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Fluid Journal : Fluid Journal 1999-2001
2 Fluid Journal Summer 2000 adjusted to maximize microbial activity. Third, and these may or may not be under control of the grower, there must be warmth, moisture and soil tilth to encourage an active microbial environment. Rains or irrigation can supply moisture, but the grower will have to depend on Mother Nature to supply the warmth. Concerning soil tilth, remember the goal of our Maximizing Soil Productivity (MSP) program is to produce a low density, deep soil that tends to also maximize microbial activity. This "mineralization" kicks loose phosphates that become one of the needed ingredients in raising high- yield crops. The mineralization process is carried out by soil microorganisms that literally feed on the residue, then die. These dead bodies make up a black material we call soil organic matter. When organic matter is finally produced, it contains a substantial amount of organic phosphorus (Table 1). Notice that in the 0 to 6-inch layer, a soil with 3 percent organic matter could contain about 1,000 lbs of phosphorus (expressed as P2O5) per acre. The organic phosphorus in this organic matter is not immediately available to the plant. This phosphate must be converted again to the inorganic form, as we mentioned before, in order to be available. But don't dismay, we aren't sliding backwards. The organic phosphate is being stored for the corn grower. It will be released into the soil in available form when the corn needs it most: in the summer months at the peak of the growing season. Through a process of "mineralization:' organic phosphorus (as well as nitrogen and other nutrients) is made available under conditions of warmth, moisture, proper pH, and good residue management. Like the rumen Another interesting way to look at it is to compare organic phosphorus in the cornfield with the rumen of a cow. Cattle feeders know that their livestock can eat tremendous quantities of silage, corn, or milo and still develop serious phosphorus deficiencies. Organic phosphorus in feed (called Phytin phosphorus) is only slightly bioavailable to animals. To make up for this deficiency, supplemental inorganic phosphorus fed to livestock in the form of monocalcium or dicalcium phosphate increases digestion. The result is 1) better feed efficiency, 2) increased weight gains, and 3) improved general health. In livestock, as well as humans, about 20 percent of the phosphorus is in the soft tissue in the form of literally hundreds of complex organic compounds. Phosphorus in soft tissue is required to metabolize carbohyrdrates and fats. It is a component of all living cells. How critical is it? When phosphorus was removed from the diet of young turkeys, they died within 10 days! A MUST ingredient In modern farming, when yields are approaching 200 to 300 bu/A, when more and more residue is being added to the soil, organic phosphorus becomes a significant consideration in residue management. Added residue need not be a problem. Instead, it can be the solution to nutrient management for high yields. Let there be no question. Organic phosphorus plays a big role in our quest for building a highly productive soil that can produce high yields.
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