Types and Distribution of Calcareous Soil in Egypt

作者：M. M. Wassif, Omnia M. Wassif · 发表于：Springer water · 年份：2021 · DOI：10.1007/978-3-030-73161-8_3 · 被引用次数：12 · 研究领域：Soil and Unsaturated Flow、Soil Geostatistics and Mapping、Soil Carbon and Nitrogen Dynamics

The calcareous soils cover a considerable portion of agricultural desert lands in Egypt, particularly in the north western coastal zone (NWCZ) and Sinai. The accumulation of carbonates in these soils is closely connected to soil genesis and formation. These soils can be defined as the soils which contain more than 14–17% total CaCO3 or more than 4–7% active CaCO3 in relation to the whole soil hydraulic properties. Some of these soils show the presence of caliche horizons. The particle size distribution of CaCO3 among the soil mechanical separates follows the textural class. These soils have variable texture sandy, loamy sand to sandy loam sandy, clay loam, silty clay loam and clay loam. The CaCO3 content varies from 10 to more than 83%. It is generally slightly and moderately to a strongly alkaline reaction where pH values of soil paste ranged from 7.4 to 9.2; organic matter content is generally low and mostly decreases with depth. Soil salinity is varies affected by agriculture system either rainfed or irrigated. In case of rainfed agriculture, it is non-saline to slightly saline, when supplemental irrigation with saline groundwater carried out the soil salinity reached to moderately saline. In case of irrigated agriculture with saline groundwater in some areas, the soil salinity reached to strongly saline. Cation exchange capacity of the soils depends on the clay percent and the CaCO3 percent in the clay and the range of 4.2 and 19.29 m.e./100 g soil. The average available ...