Prediction of water retention properties of Syrian clayey soils

• Published in: Arid land research and management Vol. 36; no. 2; pp. 125 - 144
• Main Authors: Al Majou, Hassan, Muller, Fabrice, Penhoud, Philippe, Bruand, Ary
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 03-04-2022; Taylor & Francis Ltd
• Subjects: Agricultural sciences; Arid environments; Arid regions; Arid zones; Bulk density; Cation exchange; cation exchange capacity; Cation exchanging; Cations; Chemical properties; Chemicophysical properties; Chlorite; Clay; clay content; Clay minerals; Clay soils; Drying; Earth Sciences; Exchange capacity; Field capacity; Illite; Illites; Kaolinite; Life Sciences; Mineralogy; Moisture content; pedotransfer function; Physicochemical properties; Retention; Sciences of the Universe; Semi arid areas; Semi arid environments; Semiarid environments; Smectites; Soil; Soil properties; Soil study; specific surface area; Water content; Water potential; Wetting; X rays; X-ray diffraction; Bulk density; Clay content; X-ray diffraction; Specific surface area; Cation exchange capacity; Pedotransfer function
• ISSN: 1532-4982; 1532-4990
• DOI: 10.1080/15324982.2021.1965674

Studies on clayey soils developed in temperate areas have shown that their water retention properties are related to both the clay content and the specific pore volume of the clay, the latter being related to the hydric history of the soil, that is to the drying/wetting cycles. Our objective was to discuss the validity of these results for clayey soils developed in semi-arid areas. Samples were collected in soils located in Syria. Physico-chemical properties were determined. Water content was measured at field capacity and for water potentials ranging from −10 to −15,000 hPa. X-ray diffraction analyses were performed on the clay fraction to identify the clay. Results showed that the clays have both a high cation exchange capacity (0.707-0.891 mmol+ g
−1
of clay) and a high external specific surface area (112 and 178 m
2
g
−1
of clay). These values are consistent with the X-ray diffraction results which showed the presence of a high proportion of smectite in most horizons and secondarily of varying proportions of illite and chlorite; kaolinite, while present, was not abundant. Results also showed that the amount of water retained by the clay according to the water potential was closely related to the specific pore volume of the clay at field capacity. Regression equations established by using both the data published earlier and those of this study enabled us to predict the water retention properties of clayey soils for a larger range of clay mineralogy and climatic environments including semi-arid environments than previously discussed in the literature.