Properties and characterization of vertisols developed on limestone in a semi-arid environment

Cracking soils, or vertisols, occupy a large and important part of the agricultural land in Jordan where rain-fed agriculture is practised. Six sites were selected in places where vertisols occur on limestone parent material, including different precipitation zones. The physico-chemical properties of these soils were studied in order to understand the genesis and behaviour of these soils. The climate is Mediterranean characterized by a hot dry summer and cool winter. Smectite/vermiculite, kaolinite, illite, palygorskite and quartz were the dominant clay minerals in the studied soils. The soils were subjected to different cycles of soil formation as follows: humid; arid to less humid; and to arid again.