Pedochemical Studies Of Some Zones Of Encroachment Between Tha Nile Delta And The Desert In Qalubia Governorate:

Elsayed Ahmed El-shenawy

Pedological studies were carried out on zones of encroachmentbetween the Nile Alluvial Delta soils and the neighbouringdesert sands of Eastern desert in Qalubeya. Five traverse lineswere taken and included 29 profiles extending from the Nile(Domietta branch) to the Eastern desert.Soils varied considerably from the alluvial thick~layeredfine textured near the Nile to the sandy coarse j:.e at thedesert side. Bulk density was 1.16 to 1.76 g/cm3, particle density2.52 to 2.81 g/cm3, total porosity 44 to 55%, pH 6.86 to8.60, CaC03 nil to 23.9%, gypsum was less than 1%, organicmatter: nil to 2.66%, EC 0.31 to 25 dS/m, exchangeable sodiumpercent (ESP): 3.9 to 60%.Soluble cations were dominated by Na followed by Ca then Mg;potassium was very little. Soluble anions were dominated by SO.in most profiles followed by Cl then HC03 with no C03 except in 3horizons. Cation exchange capacity CEC : 2.7 to 56.2 me/IOO gsoil dominated by Ca in most cases followed by Mg then Na and K.Light minerals of the sand fraction were dominated by quartzwhich constituted more than 96% of them, feldspars constitutedless than 4% of the light minerals. The main feldspars wereplagioclase and orthoclase with microcline being the least.Heavy minerals of the sand fraction constituted of opaques(representing 27.5-66% of them), nonopaques (9-24 pyroxenes; 8-24% amphiboles; 5 to 16% epidotes). other heavy minerals includerutile, tourmaline, zircon, garnet, kyanite, biotite, andstaurolite.Clay minerals of the clay fraction were mainly montmorillonitesfollowed by vermiculites then kaolinite and there wereinterstratified minerals. Quartz and feldspars were the majorconstituents of accessory minerals. There were calcites andapatites also.Soils of the Nile Delta were~rrerts and1forrifluvents andthose of the encroachment zones were iforrifluvents, Itorriorthents,-rorripsamments and Ealciorthids, while the desert sandswere Torripsamments, and ’lOrriorthents.Sedimentology assessments were carried out on the soils andthe indications showed water as well as wind influence on soilformation