POTASSIUM STATUS AND ITS EXTRACTION FREE ENERGY IN SOME NEWLY RECLAIMED SOILS AT UPPER EGYPT

Document Type : Research articles.

Author

Soils, Water and Environ. Institute, Agric. Res. Center, Giza, Egypt

Abstract

Eight surface soil samples (0-30 cm) were selected from some
newly reclaimed soils at Kom Ombo and Halaib & Shalateen areas,
Upper Egypt, Egypt to identify K status and free energy of extracted
K amounts. The obtained data reveal that the amounts of soluble
and exchangeable K ranged between 0.006-0.286 and 0.12-1.65 m
mol
c/100 g soil, respectively. Also, the corresponding K amounts
take place a similar parallel trend to each of soil salinity level and
the content of clay fraction, respectively.
The CaCl
2 extractable K contents from the soil samples under
consideration ranged between 0.39-0.13 and 0.05-0.02 me/100 g
soil at the first and last extractions, respectively. These obtained
data show a greater depletion between the fine and coarse textured
soils. In addition, free energy values (Δ F) of K extractions were
calculated, and the obtained results indicate that the released K
amounts from the studied soils are insufficient to cover K
requirements for grown plants, and in turn these soils are in need to
be fertilized with K, particularly upon the prevailing extensive
cropping patterns.


Keywords