Physical, Chemical And Mineralogical Studies Of Some Reclaimed Soils In Egypt :

Magdy Mohamed Abd El-salam Al Azab

The aim of this work is to evaluate the pedological characterization of some reclaimed soils of Egypt.Twenty six soil profiles were selected to represent the reclaimed soils in 4 areas EL-Shabab , El-Salhiya , El-Nobariya and El-Tina Plain and were morphologically described and sampled for physical , chemical and mineralogical analysis . Soil classification , land capability and land suitability were also done .1-Physical and chemical properties .El-Shabab soilsEl-Shabab soils (6 profiles) are clay loam to sandy clay loam in surface , sandy loam to sand in subsurface ; 1.00% to 2.95% CaCO3 ; 0.10 to 0.41% gypsum , organic mater up to 0.85% .Particle density (PD) 2.63 to 2.75 g/cm3 ; bulk density (BD) 1.30 to 1.75 gm/cm3 ; Hydraulic conductivity (HC) 6.70 to 12.40 cm/hr . Field capacity (FC) : 7.11 to 20.90 % ; Wilting point (WP) 3.96 to 8.96% ; available water (AW) 2.11 to 15.75% . Total porosity (TP) 34.7 to 59.1 % . Frequency distribution of pores : quickly drainable pores (QDP) : 4.5 to 32.1 ; slowly drainable pores (SDP): 4.1 to 22.7 % , water holding pores (WHP) : 4.5 to 21.2 % and fine capillary pores (FCP) : 5.1 to 12.2 % . Other ranges are as follows :-7.1 to 7.9 pH , 0.43 to 2.20 dSrn-1 EC ; Soluble ions : Na’ > Ca4+>Mg++>K+ ; > SO4-- > HCO3-- ; Cation exchangeSummary and Conclusion -219-capacity 3.07 to 26.91 cmolck-’g ; exchangeable cationsCa4+>Mg.”->Na4 >K+ mostly ; and MgH->Ca++>Na+>K4 in somecases . El-Salhiya soils .El-Salhiya soils (6 profiles) are clay loam or sandy clay loam in surface , sandy loam in the deepest layers , 1.00 to 1.65 % CaCO3 ; 0.10 to 0.22 % gypsum , 0.10 to 0.68 % organicmater .(PD) 2.63 to 2.77 g/cm3 ; (BD) 1.53 to 1.73 gm/cm3 ; (HC) 6.80 to 15.20 cm/hr . (FC): 9.20 to 20.00 % ; ( WP) 4.00 to 9.98% ; (AW) 2.62 to 15.19 % . (TP) 31.00 to 54.70 % . Frequency distribution of pores : (QDP) : 1.00 to 12.10 ; (SDP): 1.2 to 13.2 % , (WHP) : 2,5 to 24.9 % and (FCP): 6.5 to 13.80 %7.20 to 7.9 pH , 0.45 to 3.70 dSmi EC ; Soluble ions : Na+ >Ca++>Mg-H->K+ ; > SO4- > HCO3- ; Cation exchange capacity 3.71 to 29.55 cmolck-ig ; exchangeable cations Ca++> Nair = Mg++>K+ .El-Nobariya soils .El-Nobariya soils (7 profiles) are clay loam or sandy clay loam in surface , sandy loam or loamy sand in the deepest layers, 10.00 to 20.50 % CaCO3 ; gypsum up to 0.22 % , 0.10 to 0.85 % organic mater .(PD) 2.64 to 2.76 g/cm3 ; (BD) 1.50 to 1.76 gm/cm3 ; (HC) 6.90 to 15.30 cm/hr . (FC): 6.45 to 17.50 % ; (WP) 1.72 to -14.76% ; (AW) 1.35 to 15.76 % . (TP) 30.00 to 45.80 % .Frequency distribution of pores : (QDP) : 8.60 to 10.80 ; (SDP): 1.5 to 11.5 % , (WHP) : 6.2 to 21.00 % and (FCP): 3.2 to 12.5%.7.00 to 7.9 pH , 0.41 to 1.40 dSm-1 EC ; Soluble ions : Na+ >Ca++>Mg+-1->K+ ; CF > SO4-- > HCO3-- ; Cation exchange capacity 3.90 to 15.70 cmolck-ig ; exchangeable cations Ca++> Na+ >Mg++>K+ .El-Tina plainEl-Tina plain soils (7 profiles) are commonly clay , 1.90 to 8.10 % CaCO3 ; 1.16 to 12.20 % gypsum , organic mater up to 1.9 % .(PD) 2.57 to 2.89 g/cm3 ; (BD) 1.14 to 1.40 gm/cm3 ; (HC) 0.05 to 6.50 cm/hr . (FC): 7.78 to 36.40 % ; (WP) 5.01 to 21.47% ; (AW) 2.77 to 20.75 % . (TP) 32.70 to 66.10 % . Frequency distribution of pores : (QDP) : 3.90 to 14.40 ; (SDP): 4.8 to 11.4 % , (WHP) : 4.7 to 28.30 % and (FCP): 8.5 to 26.5%.7.70 to 8.3 pH , 3.45 to 174.00 dSm-1 EC: Soluble ions :Na+ >Ca++ and or Mg++>K+ ; Ci > SO4-- > ; Cationexchange capacity 6.51 to 57.42 cmolck-ig ; exchangeablecations Mg++> Ca++> Na+ >K+ .2-Rating of morphological properties was figured out using the relative horizon distinctness ( RFID ) and relative profile development (RPD) . Modifications of the morphological rating systems were provided . Data concerning CaCO3 , gypsum , salinity and pH have significant importance in the studied soils . Results indicate apparent discontinuity and stratification of profile layers as shown by the variations in RHD and RPD values .3-Grain Size analysis .from the grain size parameters , it can be noticed that the water and / or water and wind actions are the main factors affecting to transportation and deposition of the studied soils .4-Soil mineralogy4.1 Mineralogy of the sand fractiona . Light mineralsData indicate that the light fraction is composed almost entirely of quartz which constitutes 91.91 — 97.97 % . Other associated minerals are orthoclase , plagioclase and microcline (feldspars ) . Orthoclase and plagioclase are the main members of feldspars with less pronounced occurrence of microcline .b. Heavy minerals .The opaques are the dominant and constitute 47.40 to 63.60 % . The non-opaques are dominanted by pyroboles (pyroxenes + Amphiboles ) and epidot . Tourmaline and rutileare in moderate amounts . Garnet , staurolite , kyanite and sillimanite are of less pronounced amounts .Uniformity and development of soil profiles shows that the soils are heterogeneous either due to their multi — origin or due to a subsequent variation along the course of sedimentation . Therefore , they are young from the pedological view point .4.2 Clay mineralogyIn most soils of El-Shabab , El-Salhiya and El-Tina Plain areas , mineralogical identification of clay of fourteen samples , (using x-ray diffraction) reveals the dominance of smectite (montmorillonite ) followed by kaolinite with less pronounced occurrence of illite , chlorite and vermiculite minerals .Calcareous soils of El-Nobariya , particularly show that palygorskite mineral was the second predominant mineral after smectite . The identified accessory minerals are mainly quartz and feldspars .The mineralogical constitution of the clay fraction suggests the inheritance of clay minerals from the parent materials , except for palygorskite which may have been either inherited or geo-genetically formed under soil forming processes , stimulated by a presence of high contents of CaCO3 and soluble salts .5- Soil classificationThe investigation soils are.1- EntisolsSummary and Conctirsion-223-Sub order : Orthents 10 profiles 2-AridisolsSub order : Calcids 7 profilesGypsids one profile3- VertisolsSub order : Aquerts one profileTorrerts 5 profilesSoil moisture and temperature regimes are different into nine families .6- Land evaluationAccording to the land capability index , the soils are placed between grade 2 and 5 as follows :1-Grade (2) : ”Good soils” , represented by 4 profiles2-Grade (3):” Fair soils” , represented by 19 profiles .3-Grade(5): ”very poor soils ” represented by 3 profiles According to the land suitability index , soils are located within the following suitability classes :S2 : moderately suitable with suitability index 50 - 75S3 : marginally suitable with suitability index 25 - 50 N : non suitable with suitability index < 25Suitability for various crops was also assessed . Soils were suitable for growing 22 different crops ( 11 different field crops ; 7 different vegetable crops and 4 different fruit crops )