Release of Nonexchangeable Soil Potassium During Short Periods of Cropping and Sodium Tetraphenylboron Extraction1
- A. D. Scott and
- L. F. Welch2
Undried soils were cropped in the greenhouse to determine the short-term release of nonexchangeable K under intensive cropping conditions. Using corn root mats with plants intact, it was found that 218, 59, 50 and −1 ppm. nonexchangeable K was released in 10 days by Marshall surface and subsoil and Clarion surface and subsoil samples, respectively, that had received no NH4 or K additions. It was concluded that this short-term cropping method could be used to study factors that affect the availability of nonexchangeable soil K to plants.
Nonexchangeable K was also extracted from the undried soils by two chemical methods that tend to reduce the blocking effect of replaced K. Single extractions with a NaOAc-NaBPh4 solution removed more nonexchangeable K than five successive NaCl-HCl extractions or 5-day cropping periods. The corn plants and the NaCl-HCl solution, however, continued to remove K when the extraction period was increased whereas the NaOAc-NaBPh4 solution did not.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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