Spatial Distribution of Soil Sensitivity to Desertification in The West Delta Lands (Egypt)

Document Type : Original Article

Author

Soils and Water Department, Faculty of agriculture, AL-Azhar University, Cairo, Egypt

Abstract

Desertification is one of the most important problems facing arid and semi-arid regions, whether it is caused by irresponsible human activity or due to natural conditions or both. The objectives of the study were to assess the environmental sensitivity of desertification in the western delta region using a Mediterranean Mathematical Model (MEDALUS). Where the sensitivity of the land to desertification is deduced in this model using geographic information systems through the integration of spatial data of soil characteristics, vegetation cover, climate and management obtained from field visits and laboratory analyzes and then entered into the ArcGIS10.3 program base to derive a map of desertification sensitivity. This map was used by Stakeholders and decision-makers to propose a list of interventions that may contribute to alleviating desertification problems in the region and thus ensure their sustainable use. The results indicated that the sensitivity to desertification in the western delta region is distributed by 88% of medium sensitivity (i.e., 3,405.69 km), while the areas with high sensitivity to desertification represent 12% of the total area (i.e., 462.68 km). The results also indicated that low rainfall and poor soil properties are a determining factor in areas highly sensitive to desertification in the western Delta.

Keywords


Spatial Distribution of Soil Sensitivity to Desertification in The West Delta Lands (Egypt)

M. A. Saeed.

Soils and Water Department, Faculty of agriculture, AL-Azhar University, Cairo, Egypt.

*Corresponding author E-mail: Elansary@azhar.edu.eg  (M. Saeed)

ABSTRACT

Desertification is one of the most important problems facing arid and semi-arid regions, whether it is caused by irresponsible human activity or due to natural conditions or both. The objectives of the study were to assess the environmental sensitivity of desertification in the western delta region using a Mediterranean Mathematical Model (MEDALUS). Where the sensitivity of the land to desertification is deduced in this model using geographic information systems through the integration of spatial data of soil characteristics, vegetation cover, climate and management obtained from field visits and laboratory analyzes and then entered into the ArcGIS10.3 program base to derive a map of desertification sensitivity. This map was used by Stakeholders and decision-makers to propose a list of interventions that may contribute to alleviating desertification problems in the region and thus ensure their sustainable use. The results indicated that the sensitivity to desertification in the western delta region is distributed by 88% of medium sensitivity (i.e., 3,405.69 km), while the areas with high sensitivity to desertification represent 12% of the total area (i.e., 462.68 km). The results also indicated that low rainfall and poor soil properties are a determining factor in areas highly sensitive to desertification in the western Delta.

Keywords: Soil Quality, Climate Quality, Vegetation Cover Quality, and Management Quality.

 

INTRODUCTION

Desertification is a major problem in arid and semi-arid regions, where water is the main determinant in the process of agriculture, and soil use. The land sensitivity to desertification is a set of indicators that represent a potential risk of desertification, and it is the end result of many interactions between a set of factors, including environmental change. And human activities (Batterbury and Warren, 2001; Moghanm and Belal 2018).

About 15 percent of the world's population (more than 100 countries) of more than six billion people are affected by desertification (Adger et al., 2000, Adger et al., 2001).

  In the Mediterranean countries, different regions are sensitive to desertification, depending on the specific conditions of each region. Some areas show high sensitivity to low rainfall because they contain plants that show poor resistance to drought, have low vegetation, have gentle slopes, and major materials are highly corrosive (Ferrara et al., 1999).

The occurrence of desertification incorporates two components: human actions and natural ecosystems (World Meteorological Organization, 2005).

The MEDALUS scheme was designed and used by (Kosmas et al., 1999), and thereafter used in several studies to evaluate ESA, and from these studies (Basso et al., 2000, Gad and Lotfy, 2006, Contador et al., 2009, and Tombolini et al. al., 2016).

Symeonakis et al., 2016 that the ESA framework is the most widely applied indicator-based system for assessing land degradation and desertification primarily in the Mediterranean region.

Various studies monitored and assessed environmentally
sensitive areas (ESA) by using MEDALUS model in the Mediterranean region with acceptable results (Saleh et al., 2018, Lahlaoi et al. 2017).

MEDALUS is one of the methods used to assess the sensitivity of environments to desertification based on four main indicators: soil, climate, vegetation cover and management (Bouabid et al., 2010).

Desertification sensitivity is the extent to which the terrestrial environment responds to the adverse effect of natural or human activities.

In this context, arid and semi-arid regions, which cover about a third of the Earth's surface, are particularly threatened by desertification due to their high sensitivity to this phenomenon, as the dry climate and human pressures through intensive agriculture

The objectives of our work were to apply the MEDALUS model to assess the risks of desertification in the West Nile Delta region using geographic information systems and remote sensing tools, and to use this information as a basis for making the spatial distribution of different degrees of desertification sensitivity.

MATERIALS AND METHODS

Study area

The study area is located in the west Nile delta, north west of the Cairo city. It extends between latitudes 30° 20´ and 30° 50´ N, and longitudes 30° 10´ and 30° 50´E (Fig. 1). The Nile River in the east (Rosetta branch), the Cairo-Alexandria roads in the west the Noubaria canal in the north, and the Khatatba road in the south border. It lies over approximately 2458.60 km2 and according to Climatological Normals for Egypt, (2006) is characterized by an arid condition. The mean annual temperatures ranging from 7.2 to 34.3 oC and the mean annual precipitation ranging from 0 to 200 mm/year. According to Conoco (1987). The geological formations of the study area belonging to the Quaternary ages, as they include the following deposits: Nile silt deposits, Aeolian deposits, alluvial deposits, and deltaic deposits

The information extracted from a DEM (i.e., surface elevation, slope and slope direction) is used with the satellite images to increase their utility in physiographic soil mapping. The Landsat ETM+ images and the DEM  were merged  in the  ArcGIS to obtain the physiographic units (Dobos et al., 2000).

Field work and laboratory analyses

For field work and locating soil Profiles, a map of the physiographic units with GPS was used for this purpose (Fig. 2). Fifteen soil profiles were created to represent the different physiographic units on the map,  morphology was subsequently described, and representative samples were taken from each Profile, according to the soil survey manual (USDA 2012).

Soil samples that were collected air-dried were sieved through a 2 mm stainless steel sieve and stored in plastic bottles to be ready for the physical and chemical analyzes. The necessary analyzes were carried out to complete the study according to Estefan et al. (2013)

Land Desertification assessment

The MEDALUS model was used to determine the sensitivity of areas to desertification by calculating indicators that lead to land degradation and, ultimately, desertification.

Through the model, we can compile indicators and merge them into four quality layers that represent soil quality indicators (SQI), climate (CQI), vegetation cover (VQI) and management (MQI). The SQI and CQI reflect the environmental conditions, the Quality of Life Index (VQI) reflects human activities, and the MQI reflects the management effects of the region (Figure 3 and Table 1).

Classes and assigned weighting index for factors were calculated in detail by (Kosmas et al., 1999).

The desertification sensitivity index (DSI) was calculated and classified from the four previously computed indicators, using equation 1 and Table 2. The obtained values are to be entered in order to create a desertification-sensitive map of regions through spatial analysis of data using ArcGIS 10.3 software using inverse-weight deterministic interpolation (IDW) techniques.

DSI = (SQI × CQI × VQI × MQI)1/4 (1)

RESULTS AND DISCUSSION

Estimate quality indicators

The effect of soil characteristics related to environmental sensitivity to desertification is estimated by estimating the so-called the Soil Quality Index (SQI) depending on drainage condition, rock fragments (%), slope (%), soil texture class, soil depth (cm), and parent material type. Table 3 shows the weighted average of soil properties used in the calculation of the soil quality index. In general, the texture was sandy and sandy loam, and the depth of the Profiles was between 100 and 150 cm, except for Profile No. 12 (50 cm) and the slope was <6% and the percentage of rock fragments did not exceed 20 % except for Profiles No. 8 and 9 (average of 27%), while the drainage condition was Well to Moderately Well, except for Profile No. 12, it was Very Poorly

The results indicate as in Table (3,4) Figure (4) that the study area with high and medium soil quality index, areas of high quality (value <1.13) represent 95.80% of the total area (i.e., 3700.43 km), and the areas with medium soil quality index (value = 1.13 - 1.45) represent 4.20 % of the total area (i.e., 162.42 km2). Thus, the areas of high quality are prevalent in the study area.

The Climate Quality Index (CQI) is evaluated based on climate data as well as slope direction. The local climate varies from one place to another depending on the direction of the slope. Slope direction was inferred from a digital elevation model (DEM). The moderate climate index (1.50 - 1.80) was prevalent for most soil profiles in the study area, while it was low (> 1.80) for profiles No. 8,9,10 and 16.

Vegetation cover and management play an important role in combating desertification, the higher the vegetation cover, the less likely the soil will be exposed to erosion and vice versa, and the more there is good management, this well be the reason for the likelihood of desertification. The data indicate that the study area has a high quality of vegetation cover and management.

Soil Desertification

The previous four indicators were combined together to assess environmentally sensitive desertification areas, on the basis of the Computed Desertification Sensitivity Indicators (DSI). The results as shown in Table (5,6) and Figure (5) indicate three levels of sensitivity to desertification in the western delta region. It is noted that areas with medium sensitivity to desertification (second degree) represent the largest area at 86% of the study area, areas with medium sensitivity to desertification (third degree) represent the least area by 1.5%, while areas with high desertification sensitivity represent 12%.

CONCLUSION

Desertification is considered one of the biggest challenges in sustainable development in Egypt in general. This research should be considered as a case study related to methods for assessing and mapping sensitive areas of desertification (SAD). SAD monitoring was performed using the MEDALUS model supported by field assessments and laboratory analyzes. The results show that the MEDALUS model is a valuable tool for assessing the environmental sensitivity of desertification in arid and semi-arid regions such as the western delta in Egypt. The MEDALUS approach can also be applied in other regions, but after adding some other indicators. This increases the accuracy of the approach such as the water quality. The results indicated that 88% of the region is moderately sensitive to desertification, and 12% is highly sensitive. These results allow the identification of areas that require action to combat desertification. The approach used in this research can be used elsewhere in Egypt. The SAD map has proven to be a good source of information to assist local and national authorities in combating desertification in the West Delta region. We suggest that in order to alleviate desertification in the West Delta region, soil properties should be improved and water loss reduced through the use of appropriate agricultural rotations and attention to choosing the appropriate type of management.

REFERENCE

Adger, W.N., Benjaminsen, T.A., Brown, K., Svarstad, H. 2000. Advancing a Political Ecology of Global Environmental Discourses, University of East Anglia, London, Centre for Social and Economic Research on the Global Environment.

Adger, W.N., Benjaminsen, T.A., Brown, K., Svarstad, H. 2001. Advancing a political ecology of global environmental discourses. Development and Change, 32: 681-715.

Basso, F., Bove, E., Dumontet, S., Ferrara, A., Pisante, M., Quaranta, G., Taberner, M. 2000. Evaluating environmental sensitivity at the basin scale through the use of geographic information systems and remotely sensed data: an example covering the Agri basin (Southern Italy). CATENA, 40: 19-35.

Batterbury, S.P.J., Warren, A. 2001. Desertification. In: Smelser, N., Baltes, P. (Eds.), International Encyclopedia of the Social and Behavioral Sciences. Elsevier Press, pp. 3526–3529.

Bouabid, R., Rouchdi, M., Badraoui, M., Diab, A., Louafi, S. 2010. Assessment of land desertification based on the MEDALUS approach and elaboration of an action plan: The case study of the Souss River Basin, Morocco. In Land degradation and desertification: Assessment, mitigation and remediation (pp. 131-145). Springer, Dordrecht.

Climatological Normals for Egypt 2006. The Normal for El-Beheira and El-Monoufia Governorates from 1986 – 2006, Ministry of Civil Aviation, Meteorological Authority. Cairo, Egypt.

Conoco Coral. 1987. Geological map of Egypt 1:500 000, sheet of Cairo (NH 36 NW). Egyptian General Petroleum Corporation.

Contador, J.F. L, Schnabel, S., Gutie´Rrez, A.G., Ferna´ Ndez, M.P. 2009 Mapping sensitivity to land degradation in Extremadura.Sw Spain. Land Degrad. Develop. 20: 129–144.

Dobos, E., Micheli, E., Baumgardner, M.F., Biehl, L., Helt, T. 2000 Use of combined digital elevation model and satellite radiometric data for regional soil mapping. Geoderma, 97: 367-391.

Estefan, G., Sommer, R., Ryan, J. 2013. Methods of soil, plant, and water analysis: a manual for the West Asia and North Africa region, 3rd ed.; ICARDA: Beirut, Lebanon

Ferrara, A., Bellotti, A., Faretta, S., Mancino, G., Taberner, M. 1999. Identification and assessment of environmentally sensitive areas by remote sensing. MEDALUS. King’s College, London.

Gad, A., Lotfy, I. 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.

Kosmas, C., Gerontidis, S.T., Detsis, V., Zafiriou, T.H., Marathianou, M. 1999. Application of the MEDALUS methodology for defining ESAs in the Lesvos Island. European Commision.

Lahlaoi, H., Rhinane, H., Hilali, A., Lahssini, S., Khalile, L. 2015 Potential Erosion Risk Calculation Using Remote Sensing and GIS in Oued El Maleh Watershed, Morocco. J. Geogr. Inf. Syst. 7: 128–139.

Moghanm, F.S., Belal, A.A., 2018 Assessment and mapping of environmentally sensitive areas to desertification using new techniques in the North Delta region of Egypt. Egyptian Journal of Soil Sciences: DOI: 10.21608/ejss.2018.4155.1181.

Saleh, A.M., Belal, A.B., Jalhoum, M.E. 2018. Quantitative Assessment of Environmental Sensitivity to Desertification in Sidi Abdel-Rahman Area, Northern West Coast. Of Egypt. Egypt. J. Soil Sci. 58 (1): 13 -26.

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Table 1: Environmental properties related to desertification sensitivity indexes.

 

Algorithms

Quality index

SQI= (texture x parent material x rock fragment x depth x slope x drainage)1/6

SQI

CQI= (rainfall x aridity x aspect) 1/3

CQI

VQI= (fire risk x erosion protection x drought resistance x vegetation cover)1/4

VQI

MQI= (land use intensity x policy enforcement)1/2

MQI

Table 2: Ranges and classes of desertification sensitivity index.

Range of values

Symbol

Desertification Sensitivity Degree

1-1.17

N

non-threatened

Very LOW

1.18-1.22

P

Potential

LOW

1.23-1.26

F1

Fragile (1)

Moderate

1.27-1.32

F2

Fragile (2)

Moderate

1.33-137

F3

Fragile (3)

Moderate

1.38-1.41

C1

Critical (1)

High

1.42-1.53

C2

Critical (2)

High

1.53-2

C3

Critical (3)

High

 

 

 

Table 3: Site description and some soil characteristics to the representative soil profiles.

Profiles No.

Slope

%

Land cover & use

Parent

material

Drainage

class

Depth

cm

Texture

class

fragment %

1

0.7

Groundnut

A.D

M.W

125

LS

0.4

2

1.8

Banana

A.D

W

120

S

1.8

3

1

Groundnut

Ae.D

W

120

S

1

4

2

potatoes

A.D

W

140

S

0.9

5

1.85

Fallow after Maize

A.D

W

100

SCL

1.7

6

2.06

Grape

A.D

W

120

LS

6.5

7

2.63

Maize

A.D

W

150

S

8

8

1.7

Grapes

A.D

M.W

100

S

26

9

1.58

Pomegranate

A.D

M.W

110

LS

28

10

1.47

Mango

A.D

W

100

S

12.5

11

2.46

Lemon

Ae.D

W

130

S

1.3

12

0.16

Fallow after Rice

Ae.D

V.P

50

LS

1.4

13

2

Tomato

Mix

M.W

150

LS

0.5

14

1.94

Orange

Mix

M.W

150

S

1

15

3.67

Orange

A.D

W

150

S

1.8

16

1.2

Mango

Ae.D

M.W

110

S

2.7

MW=Moderately Well Drain, W=Well Drained, V. P=Very Poorly Drained, Mix= mixed Aeolian and fluvial, Alluvial deposits=A.D, Aeolian deposit=Ae.D

S= sand, SI= silt, C= clay,L= loam, GR=Gravel

Table 4: Summarized results of the soil quality index in the study area.

class

Description

range

Area km2

Area %

1

High

<1.3

3700.43

95.80

2

Moderate

1.3 to 1.45

162.42

4.20

     

3862.85

100.00

Table 5: Values of quality indexes for indicators used in calculating desertification sensitivity of the study area.

Profiles

SQI

Class

CQI

Classes

VQI

Class

MQI

Class

DSI

Classes

1

1.16

High

1.59

Moderate

1.34

High

1.41

High

1.365

F3

2

1.12

High

1.59

Moderate

1.34

High

1.22

High

1.307

F2

3

1.26

High

1.59

Moderate

1.34

High

1.22

High

1.345

F3

4

1.12

High

1.59

Moderate

1.34

High

1.22

High

1.307

F2

5

1.12

High

1.59

Moderate

1.37

High

1.41

High

1.363

F3

6

1.12

High

1.59

Moderate

1.37

High

1.22

High

1.315

F2

7

1.26

High

1.59

Moderate

1.37

High

1.22

High

1.353

F3

8

1.16

High

1.82

LOW

1.49

High

1.00

High

1.330

F3

9

1.16

High

1.82

LOW

1.49

High

1.00

High

1.330

F3

10

1.26

High

1.82

LOW

1.37

High

1.00

High

1.331

F3

11

1.26

High

1.59

Moderate

1.35

High

1.22

High

1.347

F3

12

1.41

Moderate

1.59

Moderate

1.35

High

1.41

High

1.437

C2

13

1.16

High

1.59

Moderate

1.35

High

1.41

High

1.367

F3

14

1.30

Moderate

1.59

Moderate

1.35

High

1.22

High

1.357

F3

15

1.26

High

1.59

Moderate

1.35

High

1.22

High

1.347

F3

16

1.30

Moderate

1.91

LOW

1.35

High

1.00

High

1.352

F3

 

Table 6: Summarized results of the sensitive area to desertification.

Range of values

Symbol

class

Area km2

Area %

1.27-1.32

F2

Fragile (2)

56.65

1.46

1.33-137

F3

Fragile (3)

3349.03

86.57

1.42-1.53

C2

Critical (2)

462.68

11.96

     

3868.36

100.00

 

   

Figure 1: location of the study area

 

 

Figure 2: Soil profiles distributed according to the main landforms of the study area

 

Figure 3: Outline for calculating the quality of indicators and sensitive areas of desertification

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 4: Spatial distribution of the soil quality index in the study area

 

Figure 5: Spatial distribution of the sensitive area to desertification.

 

التوزيع المکاني لحساسية التربة للتصحر في أراضي غرب الدلتا (مصر)

محمد احمد السيد سعيد

قسم الأراضي والمياه کلية الزراعة جامعة الأزهر بالقاهرة

* البريد الإليکتروني للباحث الرئيسي: Elansary@azhar.edu.eg

الملخــــصالعربي

يعتبر التصحر من أهم المشاکل التي تواجه المناطق القاحلة وشبه القاحلة سواء کان المتسبب النشاط البشري الغير مسئول أو بسبب الظروف الطبيعية أو الاثنين معا . کانت أهداف الدراسة هي تقييم الحساسية البيئية للتصحر في منطقة غرب الدلتا باستخدام نموذج رياضي خاص بمنطقة البحر الأبيض المتوسط (MEDALUS). حيث يتم استنتاج حساسية الأرض للتصحر في هذا النموذج باستخدام نظم المعلومات الجغرافية من خلال دمج البيانات المکانية لخصائص التربة والغطاء النباتي والمناخ والإدارة والمتحصل عليها من الزيارات الميدانية والتحاليل المعملية ومن ثم ادخالها في قاعدة برنامج   ArcGIS10.3 لاستنباط خريطة حساسية التصحر. تم الاستعانة بهذه الخريطة من قبل الجهات المعنية ومتخذي القرار لاقتراح قائمة بالتدخلات التي قد تساهم في التخفيف من مشاکل التصحر في المنطقة وبالتالي ضمان الاستخدام المستدام لها. اشارت النتائج إلى أن الحساسية للتصحر في منطقة غرب الدلتا موزعة بواقع 88٪ متوسطة الحساسية (أي 3،405.69 کم)، بينما تمثل المناطق ذات الحساسية العالية للتصحر 12٪ من المساحة الکلية (أي 462.68 کم). کما أوضحت النتائج أن انخفاض هطول الأمطار وخصائص التربة السيئة العامل المحدد في المناطق شديدة الحساسية للتصحر في غرب الدلتا.

الکلمات الاسترشادية: جودة الاراضى جودة المناخ جودة الغطاء الأخضر وجودة الادارة