Soil evolution on basalt and basic pyroclastic materials in the Golan Heights

The soils of the Golan basaltic plateau were surveyed and analyzed. Soils on uneroded plateaus range from montmorillonitic calcareous Reddish Brown Grumusols in the semi-arid areas through noncalcareous Brown Grumusols in the sub-humid areas to Brown and Red Mediterranean Soils with typical argillic horizons and dominance of kaolinitic clay in the humid parts of this region. Protogrumusols and basaltic Lithosols are found in eroded places. Volcanic cone soils in the humid Golan parts range from tuffic Regosols on the youngest cones and most eroded areas through tuffic Red Mediterrranean silty clay loam and silty loam on less eroded areas to tuffic Red Mediterranean clays on the older volcanic eruption sites and comparatively stable slopes.The weathering of the basalt is comparatively very slow, especially in the drier upland areas of the southern Golan. The weathering of the pyroclastic materials, on the other hand is fast, due to the great internal surface of this parent material.The various soils exhibit different leaching stages. A gradual disappearance of lime, decrease in pH values, increase in exchangeable H⁺ and a shift from montmorillonite clay dominance to kaolinite and similar clay types expresses the increase in the leaching degree from the dry areas to the moist ones.The textural profile of Golan soils depend on clay content and type. A soil sequence commencing with self-mulching Grumusols through various intermediate types to typical ABC Red and Brown Mediterranean Soils may be distinguished along climatic, time and drainage gradients.