Thirty one surface soil samples (0-30 cm layer) were collected from 31 locations covering the Governorate of Kalubia to asses the status of K in soil. The study involved measuring the following K forms; total (tK), structural (stK), exchangeable (xK), available (vK), water soluble (wsK) and biologically available (bK). Range of K (in μg K/g soil) in various forms were as follows: tK (858-9010), sK (779-8813), xK (74-1310), vK (65-987), wsK (5-86) and bK (12-473.
Correlations were run to relate various key constituents and parameters of soils with different forms of soil K. Mathematical methods of equations relating them which were improvised clay and silt in particular showed consistent and distinct close and positive correlation with each of tK, vK, xK, and stK. Stepwise regressions computed for predicting tK showed clay (C) and silt (Si) as the most influential parameters in predicting this form of K. As for xK the most two influential parameters components were silt (Si) and organic matter (OM). The equation are as follows:
tK = 1483 + 56 C + 72 Si ; xK = 4.39 + 7.38 Si + 104 OM
Other equations were developed using multiple regression one important equation is that of predicting of xK through the parameters of clay "C', silt "Si", OM, wK and CEC which is:
xK = 4.69 C + 5.53 Si + 81.6 OM + 1.88 wK + 1.38 CEC – 32.25
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