ASSESSMENT OF THE ENVIRONMENTAL SENSITIVITY TO DESERTIFICATION IN RELATION TO LAND PRODUCTIVITY OF SOME SOILS AT WEST EDFU, EGYPT

Document Type : Original Article

Abstract

ABSTACT
Egypt is one of the territories that have been suffering from
desertification and its unfavourable impact on socio-economy, food
security, and gregarious stability. Thus, one of the main activities of
Desert Research Centre is combating desertification in Egypt by
assessing the sensitivity of the ecosystems to desertification and
degradation vulnerability of land for resources conservation. Therefore,
this paper aimed at appraising the environmental sensitivity to
desertification in relation to land productivity of some soils at west Edfu,
Egypt using the Desertification Sensitivity Index (DSI). The research
area lies between 24º54'00" to 24º57'00"N and 32º43'30" to 32º49'30"E;
85 km2. The results showed that the studied area was characterized by
moderate soil quality with weak vegetation and hyper-arid climatic
quality indices. Based on DSI, the investigated site could be identified as
a sensitive area to desertification; with average and poor land
productivity classes of grades III, and IV, respectively. The evaluated
area is requiring particular soil management practices for best
agricultural use and combating desertification.

Highlights

4. CONCLUSIONS
This study aimed at assessing the environmental sensitivity to
desertification in relation to land productivity of some soils at west Edfu,
Egypt using the Desertification Sensitivity Index (DSI). In conclusion,
the studied site had DSI varying from 1.52 to 1.58, indicating a sensitive
area to desertification with average (III), and poor (IV) land productivity
classes. This referring to that the research area needs particular soil
management practices and applied safety environmentally techniques for
best agricultural use and reducing the sensitivity for desertification.

Keywords

Main Subjects


ASSESSMENT OF THE ENVIRONMENTAL
SENSITIVITY TO DESERTIFICATION IN RELATION
TO LAND PRODUCTIVITY OF SOME SOILS AT
WEST EDFU, EGYPT
Moamen M. El Kady1 and Yasser A. Sayed2
1Department of Pedology, Desert Research Centre, El-Matariya 11753, Cairo, Egypt
2Soils and Water Sci. Dept., Fac. Agric., Al-Azhar Univ., Assiut, Egypt
Corresponding author [e-mail: moamen.elkady@yahoo.com]
Key Words: Desertification assessment, Desertification sensitivity, Soil
Quality Index, Vegetation Quality Index, Climate Quality
Index, Edfu, Egypt
ABSTACT
Egypt is one of the territories that have been suffering from
desertification and its unfavourable impact on socio-economy, food
security, and gregarious stability. Thus, one of the main activities of
Desert Research Centre is combating desertification in Egypt by
assessing the sensitivity of the ecosystems to desertification and
degradation vulnerability of land for resources conservation. Therefore,
this paper aimed at appraising the environmental sensitivity to
desertification in relation to land productivity of some soils at west Edfu,
Egypt using the Desertification Sensitivity Index (DSI). The research
area lies between 24º54'00" to 24º57'00"N and 32º43'30" to 32º49'30"E;
85 km2. The results showed that the studied area was characterized by
moderate soil quality with weak vegetation and hyper-arid climatic
quality indices. Based on DSI, the investigated site could be identified as
a sensitive area to desertification; with average and poor land
productivity classes of grades III, and IV, respectively. The evaluated
area is requiring particular soil management practices for best
agricultural use and combating desertification.
1. INTRODUCTION
Desertification is a crucial environmental, social and economic
issue to several countries altogether parts of the globe, especially in dry
lands which cover about 41% of the Earth's surface and affect 38% of the
cosmopolitan population (Reynolds et al., 2007; Breckle et al., 2001).
David and Nicholas (1994) identified desertification that it means land
degradation in arid, semiarid and dry sub-humid areas resulting
essentially from climatic variations and unfavourable human impact.
Assorted investigations (Khanamani, et. al., 2017; Tavares et
al., 2015; Vasu et al., 2016) have been conducted to assess the
environmental sensitivity to desertification and its impact on productive
Egypt. J. of Appl. Sci., 36 (7-8) 2021 265-275
land in different regions of the Earth. These studies are greatly
contributing to information related to the desertification process.
There are many factors that can contribute to desertification; these
factors include soil, vegetation, climate, demographic and human
activities, each of these factors has different variables determining it,
(Gad and Lotfy, 2006). The most dominant degradation problems
leading to desertification in arid regions like Egypt were represented in
wind erosion and salinization (Glantz, 1977; Quintanilla, 1981; Zonn,
1981).
Gad and Lotfy, (2008) used remote sensing and GIS techniques in
mapping the environmental sensitivity areas for desertification of
Egyptian territory. They found that Egyptian territory is susceptible to
very high-to-high desertification sensitivity, however the Nile Valley is
moderately sensitive because of its vegetation cover. They concluded that
action measures concerning to desertification appraisement are essential
for the sustainable agricultural projects located in the desert oases, wadis
and interference zone.
Soils in west Edfu are promising for land reclamation projects due
to their location nearby the urban areas and availability of groundwater
resources for crop irrigation (Abdalazem et. al., 2020). So, one of the
important steps to improve the employment of its natural resources is
assessment of this soils for desertification sensitivity as a necessary stage
prior to the agricultural use.
Based on that, this paper aimed at assessing the environmental
sensitivity to desertification in relation to land productivity of some soils
at west Edfu, Egypt using the Desertification Sensitivity Index (DSI).
2. MATERIALS AND METHODS
2.1 Study area location and general characteristics
The study area is located in west Edfu, Aswan governorate-Egypt,
which lies between latitudes 24º54'00" and 24º57'00"N and longitudes
32º43'30" and 32º49'30"E, with an area about 85 km2, (Fig. 1).
According to Egyptian Meteorological Authority (2011), the climatic
regime is hot and characterized by moderate winter and very hot arid
summer typically called a desert climate. There is almost no rainfall
during the year (about 1 mm of precipitation). The average annual
temperature is 26.8 °C in Edfu. The studied area could be classified as
Hyperthermic temperature regime and Torric soil moisture regime (Soil
Survey Staff, 2014).
Geologically, the Nubia formation of Cretaceous age (Issawi,
1981) which covers all the examined area and overlies the basement
rocks, is mainly composed of sand and sandstone with clay and shale
intercalations of irregular thicknesses (Fig.2). El-Desoky and Sayed
(2019) classified the research area into three geomorphologic units
266 Egypt. J. of Appl. Sci., 36 (7-8) 2021
throughout interpreting satellite images and DTM techniques. These units
are in the following; (i) Overflow basin, (ii) River terraces, and (iii)
Decantation basin, Fig. (3).
2.2 Soil sampling and laboratory analyses
On the basis of geomorphological variation, seven soil profiles
were selected, (Fig. 3) and described morphologically in accordance with
norms of soil description, Soil Survey Manual (Soil Survey Division Staff
2012). Soil samples were collected and laboratory analyzed following the
standard methods of Burt (2014).
2.3 Land productivity appraisement
The investigated area was appraised on basis of Riquier Land
Productivity Index (RLPI) using the model produced by Riquier et al.
(1970) into; (1) poor land productivity class (grade IV) which comprise
the major part of the studied site, and (2) average land productivity class
(grade III) which covers the rest of area, (El-Desoky and Sayed 2019),
Table (1) and Fig. (4). Analytical data referred to that the studied soils
were highly affected by degradation of salinization and alkalinization.
Fig. (1): Site of the studied area
Egypt. J. of Appl. Sci., 36 (7-8) 2021 267
Fig. (2): Geology of the investigated portion, after Abdalazem et. al.,
(2020) and Issawi, (1981)
Fig. (3): Geomorphology of the studied area after El-Desoky and Sayed
(2019), and locations of soil profiles
268 Egypt. J. of Appl. Sci., 36 (7-8) 2021
Table (1) Soil properties of the studied area
Profile
No.
Slope
%
Depth(
cm)
Drainage
Status
Texture
EC
dS/m
pH
(1:25)
OM
%
CEC
(cmol(+)/
kg)
Gypsum
%
CaCO3
%
ESP
%
1 0.5-1 150
Poorly
drained
sg_scl 57.7 7.8 0.52 20 1.84 10 19
2 0.5-1 150
Imperfectly
drained
sg_sl 18.2 8.1 0.36 12 1.50 3 20
3 0.5-1 150
Imperfectly
drained
gsl 8.8 8.4 0.22 10 0.48 1 25
4 0.5-1 150
Poorly
drained
sg_scl 24.5 8.1 0.36 13 2.55 9 17
5 0.5-1 150
Imperfectly
drained
gsl 161.9 7.9 0.56 13 3.87 1 19
6 0.5-1 150
Well
drained
gls 54.8 8.4 0.36 9 1.97 1 18
7 0.5-1 150
Well
drained
sg_ls 9.9 8.5 0.23 10 0.65 1 19
Abbreviations
Texture: sg_scl (slightly gravelly sandy clay loam; sg_sl (Slightly gravelly sandy loam); gsl
(gravelly sandy loam); gls (gravelly loamy sand); sg_ls (slightly gravelly loamy sand)
EC: Electrical Conductivity
pH (1:25) pH measured in soil solution with (1g soil to 25ml water)
OM: Organic Matter
CEC: Cation Exchange Capacity
CaCO3: Calcium Carbonate
ESP: Exchangeable Sodium Percentage
Egypt. J. of Appl. Sci., 36 (7-8) 2021 269
Fig. (4): Land productivity classes of the studied area after El-Desoky
and Sayed (2019)
2.4 Assessment of the environmental sensitivity to desertification
The environmental sensitivity to desertification of the investigated
portion was evaluated using the Desertification Sensitivity Index (DSI).
The DSI was calculated according to the equation adopted from
MEDALLUS methodology, Basso et al., (2000) and the investigation
which is conducted by Gad and Lotfy, (2008) as follows;
DSI=(SQI* CQI*VQI)1/3
Where SQI is the soil quality index, CQI is the climate quality index and VQI is
the vegetation quality index. The SQI is based on rating the parent material,
slope, soil texture, and soil depth. The SQI was calculated according to the
following equation,
SQI=(Ip * It * Id * Is)1/4
Where, Ip index of parent material, It index of soil texture, Id index of
soil depth, Is index of slope gradient).
The VQI is computed on basis of rating three categories (i.e. erosion protection,
drought resistance and plant cover). It was calculated according the
following equation,
VQI=(IEp *IDr *IVc)1/3
270 Egypt. J. of Appl. Sci., 36 (7-8) 2021
Where: IEp index of erosion protection, IDr index of drought resistance
and IVc index of vegetation cover.
The CQI is appraised based on the aridity index, derived from values of
annual rainfall and potential evapo-transpiration which were extracted from
Egyptian Meteorological Authority (2011). The CQI was calculated
according to the following equation,
CQI=P/PET
Where: P is average annual precipitation and PET is average annual
potential evapo- transpiration. The Ranges and classes of DSI are
illustrated in Table (2).
Table 2: Ranges and classes of desertification sensitivity index (DSI)
Classes DSI Description
1 >1.2
Non affected areas or very low sensitive areas
to desertification
2 1.2DSI3. RESULTS AND DISCUSSION
The Soil Quality Index (SQI) was evaluated based upon the indices
of parent material, soil depth, soil texture class and slope. The geologic
map was used to deduce the nature of parent material, where the results
showed that the studied site is originated from soft to friable (i.e
calcareous clay, clay, sandy formation, and alluvium materials). Field
and laboratory analyses were used for assessing the other indices of soil
depth, soil texture, and slope. The considered soils were deep (150 cm)
and based of that, the soil depth index has nominated to take the score of
“1”. Soil texture index was classified as either “not very light to average”
or “fine to average” where it has got a score (1-1.66). The slope gradient
index showed homogeneous values and has given a score “1”.
Calculating the soil quality index (1.19-1.35), revealed that the studied
soils are characterized by moderate soil quality, (Table 3).
The vegetation plays an essential role in erosion protection, drought
resistance and soil capacity protection, (Gad and Lotfy, 2008). Based on
the previous parameters, the VQI was appraised and showed that the
estimated soils had weak vegetation quality index and sensitive to
desertification, (Table 4). This is coming back to the Saharan vegetation
which covers the investigated area with less than 40% and provides a low
capacity to increase kinetic energy caused by the impact of soil erosion
driving forces.
Egypt. J. of Appl. Sci., 36 (7-8) 2021 271
Table 3: Soil quality index (SQI) in the investigated area
Profile No. Ip It Id Is SQI
1 2 1.66 1 1 1.35
2 2 1 1 1 1.19
3 2 1 1 1 1.19
4 2 1.66 1 1 1.35
5 2 1 1 1 1.19
6 2 1 1 1 1.19
7 2 1 1 1 1.19
Abbreviations: Ip-parent material index; It-soil texture index; Id-soil depth index; Isslope
gradient index; SQI-soil quality index
Data of climate (i.e. rainfall and evapo-transpiration) related to the
studied area referred to that precipitation ranged between 0 to1 percent
annually while the average annual potential evapo-transpiration is
relatively high. This qualified the research area to be affected by the
hyper-arid climatic conditions. Accordingly, climatic quality index (CQI)
has got a score equal to 2, (Table 4).
Table 4: Vegetation and climate quality indices in the investigated area
Profile No. IEp IDr IVc VQI P/PET CQI
1 2 1.66 1 1.49
2 2 1.66 1 1.49 0.04 2
3 2 1.66 1 1.49 0.04 2
4 2 1.66 1 1.49 0.04 2
5 2 1.66 1 1.49 0.04 2
6 2 1.66 1 1.49 0.04 2
7 2 1.66 1 1.49 0.04 2
Abbreviations: IEp-index of erosion protection; IDr- index of drought resistance; IVcindex
of vegetation cover; VQI-vegetation quality index; P/PETprecipitation/
potential evapo-transpiration; CQI-climate quality index
The three former indices were driven jointly for the appeasement of
the environmentally sensitive areas (ESA’s) to desertification. On basis
of the calculated Desertification Sensitivity Index (DSI), the investigated
site could be classified as sensitive area to desertification, (Table 5) with
average and poor land productivity classes of grades III, and IV,
respectively. This means that the research area needs to particular soil
management practices for best agricultural use and combating
desertification, can be summarized in the following;
272 Egypt. J. of Appl. Sci., 36 (7-8) 2021
(1) Designing recent irrigation systems along with agricultural
drainage.
(2) Increase organic matter inputs.
(3) Use cover crops.
(4) Rotate crops.
(5) Manage Nutrients.
(6) Adding the agricultural gypsum.
Table 5: Desertification Sensitivity Index (DSI) in the investigated
area
Profile No. SQI VQI CQI DSI
1 1.35 1.49 2 1.58
2 1.19 1.49 2 1.52
3 1.19 1.49 2 1.52
4 1.35 1.49 2 1.58
5 1.19 1.49 2 1.52
6 1.19 1.49 2 1.52
7 1.19 1.49 2 1.52
4. CONCLUSIONS
This study aimed at assessing the environmental sensitivity to
desertification in relation to land productivity of some soils at west Edfu,
Egypt using the Desertification Sensitivity Index (DSI). In conclusion,
the studied site had DSI varying from 1.52 to 1.58, indicating a sensitive
area to desertification with average (III), and poor (IV) land productivity
classes. This referring to that the research area needs particular soil
management practices and applied safety environmentally techniques for
best agricultural use and reducing the sensitivity for desertification.
REFERENCES
Abdalazem, A.H. ; H.M. Khozyem ; M.A. Gamee ; A.A.M. Awad
and A.G. Mohamed (2020): Assessment of some Physical and
Chemical Properties of Soils in West Edfu Area, Aswan
Governorate, Egypt. Assiut J. Agric. Sci., 51(1):150-170.
Basso, F. ; E. Bove ; S. Dumontet ; A. Ferrara ; M. Pisante ; G.
Quaranta and M. Taberner (2000). Evaluating Environmental
Sensitivity at the basin scale through the use of Geographic
Information Systems and Remote Sensed data: an example
covering the Agri basin (southern Italy), Catena, 40: 19–35.
Breckle S.W. ; M. Veste and W. Wucherer (2001): Sustainable Land
Use in Deserts.
Egypt. J. of Appl. Sci., 36 (7-8) 2021 273
Burt, Rebecea (2014): Soil Survey Field and laboratory methods
manual. Soil Survey Investigation Report No. 51, Ver. 2.0,
Kellegg Soil Survey Laboratory, National Soil Survey Center,
Natural Resources Conservation Service, USDA, Lincoln,
Nebraska.
David, S.G.T. and J.M. Nicholas (1994). Desertification Exploding the
Myth. A book published in Wiley, New York.
Egyptian Meteorological Authority, (2011). The normal’s for Aswan
station, (1960- 2010), Ministry of Civil Aviation, Cairo, Egypt.
El-Desoky, A. I., and Y. A. Sayed, 2019. Land Productivity Evaluation
of Edfu Area, Aswan, Egypt, Using Remote Sensing and
Geographic Information System Techniques. Menoufia J. Soil
Sci., 4: 89 – 100.
Gad, A. and I. Lotfy (2008): Use of remote sensing and GIS in mapping
the environmental sensitivity areas for desertification of
Egyptian territory. eEarth Discussions is the access reviewed
discussion forum of Earth., 3: 41–85.
Gad, A. and I. Lotfy (2006): Use of remote sensing and GIS in mapping
the environmental sensitivity areas for desertification of
Egyptian territory. In: Proceedings of the Second International
Conference on Water Resources and Arid Environment 2006,
Riyadh, Kingdom of Saudi Arabia, 26–29 November 2006.
Glantz, M. H. (1977): Desertification: Environmental Degradation in
and around Arid Lands, Boulder, Westview Press.
Issawi, B. (1981): Geology of the southwestern Desert of Egypt, Geol.
Surv. Egypt. Cairo XI: 57-66.
Khanamani, A. ; H. Fathizad ; H. Karimi and S. Shojaei (2017):
Assessing desertification by using soil indices. Arabian Journal
of Geosciences, 10: 1–10.
Quintanilla, E.G. (1981): Regional aspects of desertification in Peru, in:
Combating Desertification through Integrated Development,
UNEP/UNEPCOM International Scientific Symposium,
Abstract of Papers, Tashkent, USSR, 114–115.
Reynolds, J.F. ; D.M. Stafford Smith ; E.F. Lambin ; B.L. Turner ;
M. Mortimore ; S.P.J. Batterbury and B. Walker
(2007): Global desertification: Building a science for dryland
development. Science, 316(5826): 847– 851.
Riquier, J. ; D.L. Bramao and J.P. Cornet (1970): A new system of
soil appraisal in terms of actual and potential productivity. FAO,
Soil Resources, Development and Conservation Service, Land
and Water Development Division. FAO, Rome.
Soil Survey Division Staff (2012): Soil survey manual. Soil Conservation
Service. U.S. Department of Agriculture Handbook 18.
274 Egypt. J. of Appl. Sci., 36 (7-8) 2021
Soil Survey Staff, (2014): Keys to soil taxonomy.12th ed. United States
Department of Agriculture, Natural Resources Conservation
Service, Washington, DC.
Tavares, J.D.P. ; I. Baptista ; A.J.D. Ferreira ; P. Amiotte-Suchet ;
C. Coelho ; S. Gomes and L. Varela (2015). Assessment and
mapping the sensitive areas to desertification in an insular
Sahelian mountain region case study of the Ribeira Seca
Watershed, Santiago Island, Cabo Verde. Catena, 128: 214–223.
Vasu, D. ; S.K. Singh ; S.K. Ray ; V.P. Duraisami ; P. Tiwary ; P.
Chandran and S.G. Anantwar (2016): Soil quality index
(SQI) as a tool to evaluate crop productivity in semiarid Deccan
Plateau, India. Geoderma, 282: 70–79.
Zonn, I.S. (1981): USSR/UNEP Projects to Combat Desertification,
Moscow Centre of International Projects GKNT, 33, 1981.
World Climatelogical organization (WMO): Climate and Land
Degradation, WMO No. 989, ISBN 92-63-10989-3, 2005.
تقييم الحساسية البيئية للتصحر، وعلاقته بانتاجية بعض
الأ ا رضي غرب ادفو، مصر
مؤمن محمد القاضي 1 ، ياسر عبد العال سيد 2
1 قسم البيدولوجي ، مرکز بحوث الصح ا رء ، المطرية ، القاىرة ، مصر
2 قسم عموم األ ا رضي والمياه - کمية الز ا رعة- جامعة الأزىر – أسيوط
تعتبر مصر من احدى الدول التي عانت من التصحر وتأثيره السمبي عمى الاقتصاد
الاجتماعي والأمن الغذائي والاستق ا رر المجتمعي ، ومن اجل ىذا کان أحد الأنشطة الرئيسية
لمرکز بحوث الصح ا رء ىو مکافحة التصحر في مصر من خلال تقييم حساسية النظم البيئية
لمتصحر وتدىور الأ ا رضي من أجل الحفاظ عمى الموارد.
لذلک ىدفت ىذه الورقة إلى تقييم الحساسية البيئية لمتصحر وعلاقتو بإنتاجية الأ ا رضي
ىذا و ، )DSI( لبعض أنواع التربة في غرب إدفو ، مصر باستخدام دليل حساسية التصحر
'29 24 الى " 30 º 43' 42 شمالا ،" 30 º '75 42 الي " 00 º 54' تقع منطقة البحث بين" 00
. 24 شرقا وتغطي مساحة 57 کم 4 º
وقد أظيرت النتائج أن المنطقة المدروسة تميزت بمؤشر جودة تربة من الدرجة المعتدلة
، وغطاء نباتي ضعيف ، وظروف مناخية شديدة الجفاف وبناءا عمى ذلک فان حسابات دليل
الحساسية لمتصحر اشارت الى ان المنطقة المدروسة امکن تصنيفيا بأنيا منطقة حساسة
لمتصحر ويصاحبيا وحدتين من درجات تقييم الانتاجية للا ا رضي وىما وحدة الدرجة المتوسطة
والاخرى وحدة الدرجة الفقيرة ، مما يتطمب استخدام نظم ادارة معينة لمتربة من اجل التقميل من
اخطار التصحر بيا وافضل استغلال ممکن لمز ا رعة.
Egypt. J. of Appl. Sci., 36 (7-8) 2021 275

REFERENCES
Abdalazem, A.H. ; H.M. Khozyem ; M.A. Gamee ; A.A.M. Awad
and A.G. Mohamed (2020): Assessment of some Physical and
Chemical Properties of Soils in West Edfu Area, Aswan
Governorate, Egypt. Assiut J. Agric. Sci., 51(1):150-170.
Basso, F. ; E. Bove ; S. Dumontet ; A. Ferrara ; M. Pisante ; G.
Quaranta and M. Taberner (2000). Evaluating Environmental
Sensitivity at the basin scale through the use of Geographic
Information Systems and Remote Sensed data: an example
covering the Agri basin (southern Italy), Catena, 40: 19–35.
Breckle S.W. ; M. Veste and W. Wucherer (2001): Sustainable Land
Use in Deserts.
Egypt. J. of Appl. Sci., 36 (7-8) 2021 273
Burt, Rebecea (2014): Soil Survey Field and laboratory methods
manual. Soil Survey Investigation Report No. 51, Ver. 2.0,
Kellegg Soil Survey Laboratory, National Soil Survey Center,
Natural Resources Conservation Service, USDA, Lincoln,
Nebraska.
David, S.G.T. and J.M. Nicholas (1994). Desertification Exploding the
Myth. A book published in Wiley, New York.
Egyptian Meteorological Authority, (2011). The normal’s for Aswan
station, (1960- 2010), Ministry of Civil Aviation, Cairo, Egypt.
El-Desoky, A. I., and Y. A. Sayed, 2019. Land Productivity Evaluation
of Edfu Area, Aswan, Egypt, Using Remote Sensing and
Geographic Information System Techniques. Menoufia J. Soil
Sci., 4: 89 – 100.
Gad, A. and I. Lotfy (2008): Use of remote sensing and GIS in mapping
the environmental sensitivity areas for desertification of
Egyptian territory. eEarth Discussions is the access reviewed
discussion forum of Earth., 3: 41–85.
Gad, A. and I. Lotfy (2006): Use of remote sensing and GIS in mapping
the environmental sensitivity areas for desertification of
Egyptian territory. In: Proceedings of the Second International
Conference on Water Resources and Arid Environment 2006,
Riyadh, Kingdom of Saudi Arabia, 26–29 November 2006.
Glantz, M. H. (1977): Desertification: Environmental Degradation in
and around Arid Lands, Boulder, Westview Press.
Issawi, B. (1981): Geology of the southwestern Desert of Egypt, Geol.
Surv. Egypt. Cairo XI: 57-66.
Khanamani, A. ; H. Fathizad ; H. Karimi and S. Shojaei (2017):
Assessing desertification by using soil indices. Arabian Journal
of Geosciences, 10: 1–10.
Quintanilla, E.G. (1981): Regional aspects of desertification in Peru, in:
Combating Desertification through Integrated Development,
UNEP/UNEPCOM International Scientific Symposium,
Abstract of Papers, Tashkent, USSR, 114–115.
Reynolds, J.F. ; D.M. Stafford Smith ; E.F. Lambin ; B.L. Turner ;
M. Mortimore ; S.P.J. Batterbury and B. Walker
(2007): Global desertification: Building a science for dryland
development. Science, 316(5826): 847– 851.
Riquier, J. ; D.L. Bramao and J.P. Cornet (1970): A new system of
soil appraisal in terms of actual and potential productivity. FAO,
Soil Resources, Development and Conservation Service, Land
and Water Development Division. FAO, Rome.
Soil Survey Division Staff (2012): Soil survey manual. Soil Conservation
Service. U.S. Department of Agriculture Handbook 18.
274 Egypt. J. of Appl. Sci., 36 (7-8) 2021
Soil Survey Staff, (2014): Keys to soil taxonomy.12th ed. United States
Department of Agriculture, Natural Resources Conservation
Service, Washington, DC.
Tavares, J.D.P. ; I. Baptista ; A.J.D. Ferreira ; P. Amiotte-Suchet ;
C. Coelho ; S. Gomes and L. Varela (2015). Assessment and
mapping the sensitive areas to desertification in an insular
Sahelian mountain region case study of the Ribeira Seca
Watershed, Santiago Island, Cabo Verde. Catena, 128: 214–223.
Vasu, D. ; S.K. Singh ; S.K. Ray ; V.P. Duraisami ; P. Tiwary ; P.
Chandran and S.G. Anantwar (2016): Soil quality index
(SQI) as a tool to evaluate crop productivity in semiarid Deccan
Plateau, India. Geoderma, 282: 70–79.
Zonn, I.S. (1981): USSR/UNEP Projects to Combat Desertification,
Moscow Centre of International Projects GKNT, 33, 1981.
World Climatelogical organization (WMO): Climate and Land
Degradation, WMO No. 989, ISBN 92-63-10989-3, 2005.