الفهرس 
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Abstract
This study is aimed at evaluating some desert areas in the southern part of the New Valley (of the Egyptian western desert). The studied area is bounded by longitudes 29° 30’ and 30° 30’ East and latitudes 22° 30’ and 23° 30’ North. There were by six physiographic units (pediplain of sandstone, pediplain of claystone, alluvial deposits derived from sandstone, alluvil deposits derived from claystone, Aeolian plain, playa).
Twenty one soil profiles were chosen to represent the different physiographic units, and were morphologically described; their properties were evaluated. The results could be summarized in the following:
1. Morphological characteristics of the studied area:
The soils are characterized by four groups of relief: (1) almost flat: soils of pediplain of claystone, alluvial deposits derived from claystone, alluvial deposits derived from sandstone and playa. (2) very gently undulating to gently undulating: soils of pediplain of sandstone and alluvial deposits derived from sandstone. (3) undulating to gently undulating: soils of aeolian plain. (4) undulating: soils of pediplain of sandstone.
The three physiographic units, pediplain of claystone, alluvial deposits derived from claystone and playa are generally characterized by moderately to fine texture (sandy loam to clayey), other units are characterized by coarse texture classes (sandy to sandy loam).Regarding calcium carbonate content, pediplain of claystone and aeolian plain have relatively low contents, alluvial deposits derived from sand stone and playa soil have higher CaCO3 content, other physiographic units have moderate amount of CaCO3. Regarding gypsum soil profiles are considered low gypsum content. Organic matter content in the studied area is extremely low, it is not exceeding 0.4 %.
2.Chemical properties of the studied area:
Soils are natural to moderately alkaline (pH 7.2 to 8.8). EC (saturating extract) ranged between 1.3 to 188 dS/m (non-saline to extremely saline), and most soils were moderately to extremely saline. Salinity increased with depth in most profiles.
Soluble cations are in the order: Na+>Ca’->Mg++>K+, soluble anions have the order: so45crAico3, while CO3 was absent.
Cation exchange capacity (CEC) ranged between 4.76 to 54.10 cmol/kg soil. High values are found in the playa, alluvial deposits derived from claystone and pediplain of claystone, and lower value in soils of alluvial deposits from sandstone and aeolian plain.
3.Trace elements status (micronutrients):
3.1- Iron:
The total Fe ranged widely between 2100 and 78300 mg/kg, and was closely related to soil texture and CaCO3; givingpositive correlation with each of fine sand, silt, (silt+clay) and Clay, and negatively with pH, sand and CaCO3%.
DTPA extractable Fe ranged from 0.4 to 35.88 mg/kg, having no significant correlation with soils constituents.
3.2- Manganese:
Total Mn ranged between 11.0 and 957 mg/kg, and (as Fe) was closely related to soil texture and CaCO3; positive correlation between total Mn and each silt, clay, and (silt+clay), but negatively correlation with coarse sand.
DTPA extractable Mn ranged between 0.004 to 3.42 mg/kg, having positive correlation with silt, clay and (silt+clay), and negative correlation with coarse sand.
3.3- Zinc:
Total Zn ranged between 1.8 to 455 mg/kg, having positive correlation with silt, and negative correlation with fine sand.
DTPA extractable ranged from 0.01 to 8.654 mg/kg, with negatively correlation with pH.
3.4- Copper:
Total Cu ranged between 1 to 34 mg/kg, having positively correlation with fine sand, silt, clay, and (silt+clay), but a negatively correlation with coarse sand .
DTPA extractable Cu ranged from 0.028 to 4.68 mg/kg, having a positive correlation with silt+clay .4.Macronutrients (N, P, and K) status in the studied soils:
4.1- Nitrogen:
The total N ranged between 0.0020 to 0.202 %, the lowest value is detected in aeolain plain while the highest one is detected in playa plain. The KC1-extractable N (mineral N) ranged between 0.3 to 50.8 mg/kg.
4.2- Phosphorus:
The total P ranges between 31.2 to 1200 mg/kg, the lowest value was in aeolian plain while the highest value is detected in playa plain soils. Phosphate P extracted by ammonium bicarbonate—DTPA (AB-DTPA) ranged between 0.4 to 9.6 mg/kg.
4.3- Potassium:
Total K ranged between 90.0 to 1320.0 mg/kg, the lowest in the aeolian plain soils, and the highest in the playa plain soils. The AB-DTPA-extractable K ranged between 3.0 to 305 mg/kg.
5.Soil Classification:
According to the previously mentioned field analytical results on the basis of Soil Taxonomy system (USDA 1975) of soils the current study are classified into the three orders, of aridisols, entisols and vertisols.
1- Order: Aridisols.
-Suborder: Calcids.
Greatgroup: Haplocalcids (profiles 1, 7, 10, 12 and 13).
-Suborder: Gypsids.Greatgroup: Haplogypsids (profile 4, 14, 15 and 16). 2- Order: Entisols.
-Suborder: Orthents.
Greatgroup: Torriorthents (profile 2, 3, 5, 8 and 11)
-Suborder: psamments.
Greatgroup: Torripsamments (profiles 17, 18, 19 and 20) 3- Order: Vertisols.
-Suborder: Torrerts.
Greatgroup: Haplotorrerts (21).
6. Land evaluation:
Soil were evaluated using 3 land capability and suitability systems, i.e. Land Capability Classification (LCC) of stork (1964); Sys Land suitability Classification (Sys LSC) of Sys (1991); and the FAO Land suitability classification (FAO LSC) of Sys. (1993). The 2 latter systems are closely related to each crops since they take crop-suitability into considerate.
6.1- On the basis of LCC:
soils were shown to be as follows:
1.Good soils (II), (profiles 11 and 14).
2.Fair soils (III), (1, 2, 4, 6, 7, 8, 10, 13, and 17).
3.Poor soils (IV), (9, 12, 15, 16, 18, 19, 20 and 21).
4.Non-agricultural soils (VI), (profiles 3 and 5).
6.2- On the basis of Sys LSC of Sys:
Only soil profiles which meet the capability classification grades of I to III were evaluated to determine suitability, for growing crops (4 field crops, 2 vegetable crops, 3 fruit trees).The four classes of Si (very suitable), S2 (moderately suitable), S3 (marginally suitable), and N (Non-suitable) were encountered in the study area.
6.3- FAO LSC:
The studied soil profiles have the five classes of Si (highly suitable, (S2) moderately suitable, (S3) marginally suitable, (Ni) currently not suitable, and (N2) permanently not suitable, were encountered in the study area.