Studies on some Physical and Chemical Properties of Sirt Area Cultivated Soils.

This investigation has been conducted on the cultivated soil of  Sirt area, Libya, that located 450 kilometers from  East of  Libyan capital Tripoli and  between the coordinates 16°35´  E and   31°12´  N to study the potassium status in some soils of Libya.  Forty-two soil samples were taken at the two different depth (0-20 and 20-40 cm) from 21sites to evaluate some physical and chemical parameters for soils  such as mechanical analysis , total carbonate,  organic matter , EC , pH, soluble cations (Ca⁺⁺, Mg⁺⁺, Na⁺ and K⁺), anions (CO₃⁼, HCO₃^-, Cl ^- and SO₄⁼) ,  total K , available K , soluble water K, exchangeable K and non exchangeable K. Coordinates of cultivated soil samples were recorded using the Global Positioning System (GPS). Studied parameters were analyzed graphically by contour maps to show the spatial distribution of chemical constituents of the different soil samples. The results indicate that the majority of soil textures in the investigated area were Sandy Loam. The all soil samples at the studied area are poor in organic matter. The soil samples electric conductivity (EC) was suitable for agricultural purposes. (The highest value of total K in both depths was found in 0-20 depth   and the lowest value was found in   20-40 depth) .Positive correlation was found between the total potassium and the clay content. (The highest values of available K in soil samples were found in 20-40 cm depth. In contrast the lowest values were found in 20-40 cm depth). The highest values of  water soluble K (meq100g^-1soil) in studied soil samples  of both depths were  found in 20-40 cm depth, also the lowest values were  found in 0-20 and 20-40 cm depth, respectively. (The highest values of non exchangeable K (meq100g^-1soil) content in studied soil samples   of both depths were found in 0-20cm depth   ,also the lowest values were  found in 0-20 cm depth)  . The soil samples at the studied area are poor in total K, available K, soluble water K, exchangeable K and non exchangeable K.