SOIL OF KARST REGION ALONG THE ADRIATIC COAST IN YUGOSLAVIA

Abstract

The Mediterranean red soil on the Adriatic coast was studied by making chemical analysis. The results were examined in relation to the climatic factors.
The red degree of soil color increases in the area south of Zadar, where the content of Free Fe is large and that of C is small. There found no relation between the annual precipitation, annual temperature, accumulated temperature over than 10°C or Lang's rain factor R=P/T. But the degree of soil color shows clear relation to the moisture index (Im), and water deficiency (d) defined by Thornthwaite (1948). Under the same condition of d, Free Fe increases with decreasing Im. In the case of the same Im values, a reverse relationship between Free Fe and d was found. As the region has the Mediter-ranean climate, water deficit concentrates in summer. So that, if Im has the same value, Free Fe contents becomes larger in the case of smaller water deficit in summer, which means increasing chemical action of red soil in warmer season. However, Free Fe contents are conditioned not by Im, but probably by the other factors, when the d value is zero.
Ca and Mg contents have no clear relation to the annual precipitation, but have to the Im and d values.