Changes in the Rhizosphere Due to NH4+ and NO3- Fertilization and Phosphorus Uptake by Corn Seedlings (Zea mays L.)1
- Y. K. Soon and
- M. H. Miller2
Corn (Zea mays L.) seedlings were grown for 11 days on 3 soils of pH 7.1, 5.5, and 4.3, and fertilized with monocalcium phosphate, and either (NH4)2SO4, Ca(NO3)2, or CaCl2.
Rhizocylinder (roots plus adhering soil) and bulk soil solutions were isolated by centrifugal filtration and analyzed for pH and phosphate.
The pH of the rhizocylinder solution was lowered by the absorption of NH4+ and increased slightly by NO3- absorption. Reduced rhizocylinder pH was associated with increased rhizocylinder solution phosphate concentration and P uptake by corn seedlings. The difference in P absorption between NH4+-fertilized and NO3--fertilized corn can be explained by induced changes in the H2PO4-concentration associated with rhizocylinder pH. But, in addition, NH4+ and NO3- enhanced P absorption probably as a result of increased physiological capacity to absorb P and/or increased root growth.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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