ملخص رسالة الدكتوراه للسيد/أحمد إبراهيم الدسوقى

main challenge facing the national development in Egypt is being located within the
The study area is considered as a main region that represents most of these
agricultural development facing the pressure of the inevitable food
their soil attributes in an area that has important situation for the
the western outskirts of Samalut
city (El-Minia Governorate)
The northern portion, which is
was
. The investigated area is approximately bounded by longitudes
29^o 00^- 00⁼ and 30^o30^-00⁼
East and latitudes 28^o 00^- 00⁼ and 29^o
00^- 00⁼ North. It is about 150 km in width and 320 km in
length and is oriented roughly in north to north east direction, located to the
southwest of Cairo
at about 300 km.

The most common geological formation that exists in the
investigated area is TERTIARYwhich is divided into:-

A – Oligocene (Gebel Qatrani Formation).

B - Eocene
- Abu Muharik Formation.

- Mokattam Group (Hamra, Qazzun and
Samalut Formation).

- Minia Formation.

- Thebes Group (Naqb Formation).

- Qasr El-Sagha Formation

According to the
geomorphological map, the main landform units covering the area under study are
the platforms (Eocene platform, structural karstified platforms, limestone and
gravely platforms). While morphological description, chemical and physical properties of soils,
representing the couple of landforms encountered in the study area show the
following physiographic units:-

1- Eocene karsified platforms
(limestone), shallow gravelly soils.

2- Soils of older deltaic plain

a- Older deltaic plain gravelly soils
with underlying caliche

b- Eroded gravelly soils with exposed
caliche

c- Remnant of Eocene plateau (Mesa).
The mean diameter of Eocene karstified platforms (profile 1, 2 &12)
falls between very coarse sand to fine sand. Sorting coefficient values are
designated poorly sort to very poorly sort without consistent trend with soil
depth. The results suggest that transportation of particles was mainly by
water. Skewness values changed from nearly symmetrical to strongly fine to fine
skew. Data of Kurtosis show that the sediments constituting of this
physiographic unit is platykurtic to leptokurtic. Leptokurtic values illustrate
that water and wind are the main factors of sediments transport while
platykurtic values indicate that water is the main factor in the soil
formation.


The mean diameter of the soils of older deltaic plain with underlying caliche
(profile 3, 4, 5, 10 &11) falls between very coarse sand to medium or fine
silt. Sorting coefficient values are designated poorly sort to very poorly sort
almost decreased with soil depth. Skewness values changed from nearly
symmetrical to strongly fine skewed. Data of Kurtosis show that the sediments
constituting of this physiographic unit is very platykurtic to very
leptokurtic.

The mean diameter of soils of eroded gravelly with exposed
caliche (profile 6 &7) falls between very coarse sand to medium sand. Sorting
coefficient values are designated poorly sort to very poorly sort. Skewness
values changed from nearly symmetrical to strongly fine skewed or very positive
skewed. Data of Kurtosis show that the sediments constituting of this
physiographic unit is very platykurtic to extremely leptokurtic.

The mean diameter of soils of the remnant of Eocene plateau, Mesa, (profile 8 &9)
falls between very coarse sand to fine sand. Sorting coefficient values are
designated poorly sort to very poorly sort. Skewness values changed from
strongly coarse skewed to strongly fine skewed or very positive skewed. Data of
Kurtosis show that the sediments constituting of this physiographic unit is
very platykurtic to very leptokurtic.

The frequency distribution values of light minerals (sp. gr.
<2.85) of the soils understudy lay in the range between 90.51 and 99.44%.
The data show that the percentages of light minerals are much higher than those
of the heavy minerals. The results show that quartz constitutes the main
fraction followed by calcite then feldspars. However, the frequency
distribution of light minerals exhibits an irregular distribution pattern with soil
depth. Variation in the content and distribution of quartz, calcite and feldspars
of the studied soil profiles are mostly ascribed to the nature of parent
materials as well as the barren nature and young age of soils that result in no
clear signs of development.

The index figures are relatively low in most soil samples. They range from
1.52 to 9.29 for Eocene karsified platforms (limestone), from 0.67 to 7.42% for
older deltaic plain with underlying caliche, from 2.06 to 10.49% for eroded
gravelly soils with exposed caliche and from 0.57 to 7.37% for remnant of
Eocene plateau (Mesa)
physiographic unit. The index figure values generally fluctuated with depth in
most cases. The index figure differs from one site to another. This may be
rendered to many factors such as variations in nature of the soil parent
materials, energy of transportional environment and the differential weathering
strength of the same parent material deposited in different cycles. The
obtained relatively low values of index figures fall in the range of some
formations of either calcareous or siliceous nature, such as limestone and
sandstones which may indicate an elementary weathering stage.


The relatively high
contents of heavy minerals in the deepest layers may be associated with the
sedimentation regime rather than the effect of weathering processes. Microscopic
inspection of the studied soil samples shows that opaques minerals are the most
abundant minerals. The non-opaque is less abundant and includes zircon,
epidotes, amphiboles, pyroxenes, tourmaline, rutile, staurolite, garnet,
kyanite, boitite and other minerals in decreasing amount. Remain heavy minerals
are existed in a miner amounts and could be arranged in descending order of
rutile > garnet > tourmaline > kyanite > staurolite > biotite
> andalusite apatite. The abundance of zircon and epidotes minerals (which
are considered to be more resistant relative to those susceptible to weathering)
may suggest an enrichment of parent materials with the ultra-stable minerals
rather than pronounced maturity and soil development. On the other hand,
relatively low and inconsistent values of resistant minerals indicate that
these soils are composed of stratified geological sediments and the pedogenic
processes are minimal and/or at very recent stages. Moreover, the occurrence of
epidotes in moderate contents, as well as the minor amounts of both
ultra-stable (zircon, tourmaline and rutile) and parametamorphic (staurolite
and kyanite) minerals may reflect the contribution of a crystalline metamorphic
and sandstone as parent materials for these soils. Also, the discrepancies
between percentages of each mineral downward the profiles are probably caused
by the depositional regime, which prevails during, soil formation.


The ratios of resisting minerals Zr/R, Zr/T and Zr/R+T do not,
generally, have any specific trend, either among profile sites or with depth of
all locations. Accordingly, soil material of each profile is not uniform in
nature and is composed of stratified materials probably of multi-origin and/or
derived from parent materials of heterogeneous nature. Uniformity ratios,
however, are about the same in all inspected depth. This suggests that the soil
materials are almost uniform throughout the soil profile due to homogeneity of
resulted sediments and the low effect of pedoginic processes.


Inspection of weathering ratio of soil samples reveals irregular
distribution pattern among either layers or sites. This is expected due to
stratification of soils from different parent materials of heterogonous nature
and/or multi­-depositional regimes. However, in some profiles, the weathering
ratios are relatively lower in the surface than the subsurface layers. Unless
uniformity is assessed any weathering trend is not confirmed. The occurrence of
the resistant minerals in relatively higher and pronounced amounts is certainly
due to original sediments.


X-ray diffraction patterns of the clay fraction denote
that the clay minerals are mainly Kaolinite and Mica. Feldspars, Quartz, Vermiculite
and Palygorskite are detected as accessory minerals. With respect to the origin
of the obtained clay minerals and their relation to the prevailing
environmental conditions of the studied area, it seems that all the identified
minerals are entirely inherited from the parent materials dominating the
studied area. However, some weathering and alteration had probably taken place
during the past geologic times which resulted in the formation of those clay
minerals. However, the very low percentages of clay fraction are denoting non
appreciable weathering. The appreciablity of feldspars and kaolinite may an
indication of the transformation of feldspars to kaolinite.


According to the climatic
data of the Meteorological Authority of Egypt (2005), the moisture regime of
the study area is "torric" and the temperature regime is
"hyperthermic". Soil characteristics of the study area were
classified in the two orders of Aridisols and Entisols to the soil family
level.


1. Aridisols


- Calcic Haplosalids, sandy, mixed,
hyperthermic (profile 5)


- Typic
Haplocalcids, sandy-skeletal, carbonatic, hyperthermic (profile 2)


- Typic Haplocalcids,
sandy,hyperthermic (profile 4 & 6)


- Gypsic Calcic Haplosalids, sandy,
mixed,hyperthermic (profile 7, 8 & 12)


- Gypsic
Calcic Haplosalids, sandy-skeletal, mixed, hyperthermic (profile 9 & 11).


2. Entisols


- Typic
Torriorthents, sandy-skeletal, mixed, hyperthermic (profile 10)


- Lithic
Torripasmments, sandy, mixed, hyperthermic (profile 1)


- Typic
Torripasmments, sandy, mixed, hyperthermic (profile 3)


Generally, the soils
understudy is pedologically young and are weakly developed. This is the result
of the prevailing arid climate that promotes physical weathering rather than
chemical changes. In other words, the course of soil forming factors is not
sufficient to cause any clear alteration. Moreover, processes of soil
formation, in such locations, are usually interrupted by alternative water and
wind actions. Also, in arid seasons, wind and gravity actions work together in
transporting fine soil materials to different locations according to slopes.
Accordingly, in this area, studies concerned with soil genesis and development
are usually faced with many obstacles. Introduce the
area to be collectively studied for other purposes of investments as well as
mapping the area at the level of detailed soil survey to enrich the area data
base in order to be developed. Therefore,
good and detailed knowledge of various local conditions, as well as, back
history of every site are greatly required.