Phosphate—Ammonium—Moisture Relationships in Soils: II. Ion Concentrations in Leached Fertilizer Zones and Effects on Plants1
- R. W. Blanchar and
- A. C. Caldwell2
Radioactive fertilizer pellets MCP32, MCP32 + NH4Cl, and MCP32 + KCl were placed in a Dakota sandy loam and allowed to react for 2 weeks. The pots containing the fertilizer were then leached with 0, 2, 4, and 8 cm of water. Corn (Zea mays) was grown on these pots for 2 weeks and analyzed for total and radioactive P. Results showed only trace amounts of fertilizer P taken up from all nonleached pots. Leaching the pots with 2 or more centimeter of water resulted in a significant uptake of fertilizer P. When the pots were leached with 4 cm of water, P uptake from MCP + NH4Cl pellets was nearly 3-fold that of either MCP or MCP + KCl. Measurement of water-soluble P and other conditions in the fertilizer zone indicated no differences between MCP + NH4Cl and MCP + KCl pellet zones. It was concluded that ammonium increased the capacity of the plant to absorb P and did not affect the availability of P in the soil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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