ENVIRONMENT SENSITIVITY MAPS OF LAND DEGRADATION AND DESRTIFICATION USING MEDULAS MODEL AND REMOTE SENSING IN SHIRQAT CITY/IRAQ

This research of aims to study environment sensitivity of desertification and land degradation using MEDULAS project and remote sensing in AL-Shirqat City/Salahadin/Iraq. A 10 soil pedons were chosen from study area depending on difference in soil preperties, landuse and causes of desertification and degradation as (Salinity, Erosion, Gypsum and vegetation cover). Soil profile description, soil samples and GPS were conducted. The physical (texture) and chemical (CaCO3, CaSO4.2H2O, O.M, EC and pH) properties were determined. The Soil were classified as Torrifluvents in the (P1, P2, P3), Torripsamments in the (P5 and P7), Calcigypsids in the (P6, P8 and P10) and Calcids in the P4. The landsat 8 image at 20sep. 2019 and 19 sep. 2013 were aquired in the spectral indices calculate and spatial maps by using ERDAS 15 and GIS 10.2. The result show contrast in soil propreties as sand, clay, soil gypsum, CaCO3, OM and EC that reflect on Soil Quality Index (SQI) which were (60)% poor quality and (40)% moderate quality degradation. While (19.10) % that moderate quality and 80.90% that poor quality for Vegetation Quality Index. The results show that 0.1% of the study area is classified as C1; 25.35% as C2; 74.55% of the areas as C3. The spectral indices as LAI, SI5, OSAVI were approporiate for monitor of desertification and degradation in study area. Add, spatial change in the spectral indices as NDVI and LAI. The results shown that MEDALUS model is a important model in the areas disposed to desertification and degradation. Key word: Remote sensing, MEDULAS project, NDVI, Desertification, LAI. يعارزلا مولعلا ةلجم ةيقارعلا ة 2021 : 52 ) 3 :) 697 711 نيسحو فلخ جذومنا مادختساب يضا رلاا روهدتو رحصتلل ةيئيبلا ةيساسحلا طئا رخ MEDULAS ءاضق يف يئانلا سسحتلاو قا رعلا/نيدلا حلاص /طاقرشلا . نيسح ءافص تايا فلخ للهادبع دايا دعاسم ذاتسأ ةثحاب ةيئاملا دراوملاو ةبرتلا مولع مسق ةعا رزلا ةيلك تيركت ةعماج :صلختسملا دهي عورشم مادختساب يضا رلأا روهدتو رحصتلل ةيئيبلا ةيساسحلا ةسا رد ىلإ ثحبلا اذه ف MEDULAS / طاقرشلا ءاضق يف يئانلا سسحتلاو رايتخا مت .قا رعلا / نيدلا حلاص 10 رحصتلا بابسأو ضرلأا تامادختساو ةبرتلا صاوخ يف فلاتخلال اعبت ةسا ردلا ةقطنم نم ةبرت تانودب لا( لثم روهدتلاو مادختساب عقاوملا تيبثتو ةبرتلا جذامن لاصحتساو يجولوفروملا فصولا ءا رجإ مت .)يتابنلا ءاطغلا ،سبجلا ،ةيرعتلا ،ةحولم ( ةيئايميكلاو )ةبرتلا ةجسن( ةيئايزيفلا تافصلا ريدقت مت .يملاعلا عقاوملا ديدحت ماظن CaCO3 ، CaSO4.2H2O ، O.M ، EC ، pH مت .) اهنأ ىلع ةبرتلا فينصت Torrifluvents عقاوملا يف P1 و P2 و P3 و Torripsamments عقاوملا يف P5 و P7 و Calcigypsids يف عقاوملا P6 و P8 و P10 و Calcids يف P4 تاسدنلا ةروص ىلع لوصحلا مت 8 يف 20 لوليا 2019 و 19 لوليا 2013 باسح يف مادختساب ةيناكملا طئا رخلاو ةيفيطلا تا رشؤملا ERDAS 15 و GIS 10.2. نيطلاو لمرلا لثم ةبرتلا صئاصخ يف انًيابت جئاتنلا ترهظأ و لا مويسلاكلا تانوبراكو سبج و ةيوضعلا ةداملا ةيئابرهكلا ةيلاصيلااو ةبرتلا ةيعون رشؤم ىلع سكعنت يتلا فنصلا امهو نيفنص لمش يذلاو ريقفلا poor هتحاسمو ( 60 ( لكش يذلاو ةيعونلا لدتعملا فنصلا و ٪ ) 40 يتابنلا ءاطغلا ةيعون رشؤم اما .ةسا ردلا ةقطنم ةحاسم نم٪ ) ( تناكف 19.10 طسوتم ٪ ) ةيعونلا و 80.90 ٪ ريقف ةيعونلا . ترهظأ جئاتنلا نأ 0.1 ٪ نم ةحاسم ةسا ردلا فنصلا تحت تناك C1 و ؛ 25.35 فنصلا تحت ٪ C2 و 74.55 تفنص قطانملا نم ٪ C3 ةيفيطلا تا رشؤملا تناك .. LAI و SI5 و OSAVI رحصتلا دصرل ةبسانم ةلدلال ةيفيطلا تا رشؤملا يف يناكم رياغت كانهو ةسا ردلا ةقطنم يف روهدتلاو NDVI و LAI . جذومن ناف اذل MEDALUS يف مهم جذومن وه روهدتلاو رحصتلل ةضرعملا قطانملا . جذومن ،يئانلا سسحتلا :ةيحاتفملا تاملكلا MEDULAS د ،يضا رلأا روهدتو رحصتلا ، ليل LAI ، NDVI . Received:22/4/2020, Accepted:8/7/2020 Iraqi Journal of Agricultural Sciences –2021:52(3):697-711 Khalaf & Hussien 698 INTRODUCTION Desertification is important pheno-mena in arid and semi-arid environments. In the context of the EC MEDALUS (Mediterranean Desertification and Land Use), the focus here is primarily on European Mediterranean environments where physical loss of soil by wind erosion, water erosion, salinization, overgrazing and loss of nutrient status in soil. Wind erosion, salinization and drought are more problems affected in arid and semi arid. Land degradation is among the most serious environmental problems at global, regional, and local scales (13) which leads to a depletion of soil fertility and productivty loss. One third of the world's drylands have already lost more than 25% of their productive capability. Each year the world loses 10 million ha of land for desertification and approximate 30% of the Earth's surface area is at risk of desertification affecting one billion people worldwide almost two billion people are located over the dryland (22). The more studies are depend on medulas project in evaluatation of soil degradation, land degradation and desertification at the large scales (2,6,13,15,16,19,20,27). Assessment of the sensitivity of the soil in the rural area of Čukarica municipality to the processes of degradation is considered.The results obtained show that 41.54% of the study area is classified as critical; 22.34% of the surface as fragile; 8.47% of the areas are potentially endangered and 9.58% not threatened to degradation processes (18). Kadović et al., 2016 was used MEDALUS for detection and evaluation of land degradation in Deliblato sands. Remote sensing technique has great value in monitoring desertification and land degradation. use of remote sensing (RS) and Geographic Information System (GIS) for Change Detecting Spatial and Temporal Variability of Soil Salinity in Al-Latifiya Project, Iraq (9). depending more than satellite images and spectral indices as (NDVI, VI, TNDVI, SAVI, MSAVI, IPVI) in northern iraq and the results ensured on the possibility of using of technique remote sensing as a device active and accurate in estimated size of area of degradation and desertification which extended to rangelands especially in the last few years (3). The determine soil deterioration degree based on NDVI to that were in the range of moderate to severe deterioration. Some physical deterioration as represented by soil texture, coarse sand texture, and chemical deterioration due to high level of salinity on some locations. The high level of gypsum and biological deterioration indicated by low level of organics and missed plant cover (26). The present study aimed to assess the environmental sensitivity of desertification and land degradation in the Shirqat district in Salah Al-Din Governorate / Iraq using the Medulas model and remote sensing. MATERIALS AND METHOD Study area. The Sharqat district is located between longitudes (42 ° 52'31.77 "E and 42 ° 58'43.756" E) and two latitudes (35 ° 39'41.352 "N and 35 ° 15'27.392" N) in the northern part of Salah Al-Din Governorate / Iraq. Its area is approximately (1577) km 2 and had the population 220000. An study area of 214.99 km 2 was chosen for the study, based on the variation in soil properties according to the physiographic units (Alluvial soils, mountain and Aldesert Jazeera soils but according to Soil Survey Staff (2006) are classify Torrifluvents (P1, P2, P3), Torripsamments(P5, P7), Calcigypsids(P6, P10) and calcids(P8, P9). It suffers from several causes of desertification phnomena as (wind erosion, water erosion, salinization, sand movement, overgrazing and gypsum content). As well as, agricultural exploitation, the quality of irrigation water and mismanagement. Average annually rainfall ranges between 150 250 mm, average maximum temperatures range between 13.5 42.50 C°, and minimum temperatures range between 3.3 26.2 C°. the mean temperature is increase in July and August, and lowest in January and February. The several locations were selected which involve (10) ten pedon and its morphological description was done according to the (Soil Survey Staff 2006). In addition, the coordinates of the study location were determined using GPS. Soil samples were taken and transferred for laboratory, and the soil physical (Soil Texture) and chemical properties (OM, CaCO3, CaSO4.2H2O) were determined in the Department of Soil Science and Water Resources at the Tikrit University. Slope was analyzed using the DEM Digital Elevation Model and ArcGIS Ver 10.2 software and ranged between 0-19.5% as (Fig.1). Iraqi Journal of Agricultural Sciences –2021:52(3):697-711 Khalaf & Hussien 699 Fig. 1. Map of Study area and DEM Medalus project. The environment sens-itivity to land degradation and deserti-fication are defined using the Environmental Sensitive Area Index (ESAI) according to the model data (Kosmas et al., 1999; Kosmas et. al. 2014, Kadović, 2016; Lamqadem, 2018; Zambon, 2017; Mostafa, 2020). The Soil Quality Index (SQI), Climate Quality Index (CQI), Vegatation Quality Index (VQI) were used. Spatial distribution maps of Soil quality indices, vegetation quality indices and environment sensitivity were conducted using ArcGIS Ver 10.2. The areas of environmental sensitivity classes of land degradation and desertification were calculated using the inverse distance method. Soil quality index For the soil quality estimation one topographic (slope) and seven soil properties (soil texture, EC, organic matter, calcium carbonate, soil gypsum, rock fragment of surface layer and soil Albedo) were selected. Soil quality index (SQI) was calculated as following equation: Soil Quality Index-SQI=(X1×X2 .......Xn) 1/8 (1) then X= Soil properties as mentioned in table (1) respectively. Iraqi Journal of Agricultural Sciences –2021:52(3):697-711 Khalaf & Hussien 700 Table 1. Classes, description, and assigned weighting indices for the parameters. Parameter Class Description Susceptibility class Weight index Soil Texture 1 Good L, SCL, SL, LS, CL 1 2 Moderate SC, SiL SiCL 1.2 3 Poor Si, C, SiC 1.6


INTRODUCTION
Desertification is important pheno-mena in arid and semi-arid environments. In the context of the EC MEDALUS (Mediterranean Desertification and Land Use), the focus here is primarily on European Mediterranean environments where physical loss of soil by wind erosion, water erosion, salinization, overgrazing and loss of nutrient status in soil. Wind erosion, salinization and drought are more problems affected in arid and semi arid. Land degradation is among the most serious environmental problems at global, regional, and local scales (13) which leads to a depletion of soil fertility and productivty loss. One third of the world's drylands have already lost more than 25% of their productive capability. Each year the world loses 10 million ha of land for desertification and approximate 30% of the Earth's surface area is at risk of desertification affecting one billion people worldwide almost two billion people are located over the dryland (22). The more studies are depend on medulas project in evaluatation of soil degradation, land degradation and desertification at the large scales (2,6,13,15,16,19,20,27). Assessment of the sensitivity of the soil in the rural area of Čukarica municipality to the processes of degradation is considered.The results ob-tained show that 41.54% of the study area is classified as critical; 22.34% of the surface as fragile; 8.47% of the areas are potentially endangered and 9.58% not threatened to degradation processes (18). Kadović et al., 2016 was used MEDALUS for detection and evaluation of land degradation in Deliblato sands. Remote sensing technique has great value in monitoring desertification and land degradation. use of remote sensing (RS) and Geographic Information System (GIS) for Change Detecting Spatial and Temporal Variability of Soil Salinity in Al-Latifiya Project, Iraq (9). depending more than satellite images and spectral indices as (NDVI, VI, TNDVI, SAVI, MSAVI, IPVI) in northern iraq and the results ensured on the possibility of using of technique remote sensing as a device active and accurate in estimated size of area of degradation and desertification which extended to rangelands especially in the last few years (3). The determine soil deterioration degree based on NDVI to that were in the range of moderate to severe deterioration. Some physical deterioration as represented by soil texture, coarse sand texture, and chemical deterioration due to high level of salinity on some locations. The high level of gypsum and biological deterioration indicated by low level of organics and missed plant cover (26). The present study aimed to assess the environmental sensitivity of desertification and land degradation in the Shirqat district in Salah Al-Din Governorate / Iraq using the Medulas model and remote sensing.  '27.392" N) in the northern part of Salah Al-Din Governorate / Iraq. Its area is approximately (1577) km 2 and had the population 220000. An study area of 214.99 km 2 was chosen for the study, based on the variation in soil properties according to the physiographic units (Alluvial soils, mountain and Al-desert Jazeera soils but according to Soil Survey Staff (2006) are classify Torrifluvents (P 1 , P 2 , P 3 ), Torripsamments(P 5 , P 7 ), Calcigypsids(P 6 , P 10 ) and calcids(P 8 , P 9 ). It suffers from several causes of desertification phnomena as (wind erosion, water erosion, salinization, sand movement, overgrazing and gypsum content). As well as, agricultural exploitation, the quality of irrigation water and mismanagement. Average annually rainfall ranges between 150 -250 mm, average maximum temperatures range between 13.5 -42.50 C°, and minimum temperatures range between 3.3 -26.2 C°. the mean temperature is increase in July and August, and lowest in January and February. The several locations were selected which involve (10) ten pedon and its morphological description was done according to the (Soil Survey Staff 2006). In addition, the coordinates of the study location were determined using GPS. Soil samples were taken and transferred for laboratory, and the soil physical (Soil Texture) and chemical properties (

Soil quality index
For the soil quality estimation one topographic (slope) and seven soil properties (soil texture, EC, organic matter, calcium carbonate, soil gypsum, rock fragment of surface layer and soil Albedo) were selected. Soil quality index (SQI) was calculated as following equation: Soil Quality Index-SQI=(X1×X2 …….Xn) 1/8 (1) then X= Soil properties as mentioned in table (1) respectively. Erosion. The index for soil erodibility is express the product of multiplying the wind erosion, water erosion, and soil crust index E = EF×WEF×SCF (5) Where, EF Wind erodible Fraction, WEF-Water erodibility and SCF-Soil Crust Factor as fallowing: Erodible Fraction-EF. The wind erosion hazard is severe in regions of low precipitation and high temperatures and wind velocity where soil is bare. The risks of wind erosion are exacerbated by wind blowing across long, bare fields on soils of single-grain or weak structure and having a loamy texture (Lal et. al., 2004). It depends in its calculation on soil characteristics that decrease soil erodibility to wind erosion as (organic matter and clay) or increase soil erodibility to wind erosion as (sand content and structurless) as following equation (Fryrear et al., 2000). According to Dregne (1983) criteria were classified as Sligh-tly, Moderate, Sever, and very sever degradation. EF=29.09 + (0.31× sand%+ 0.17×silt% + 0.338×sand/clay% -4.66×OM%-0.95× CaCO 3 %)/100.. (6) Water erodibility Index -WEF: Sandy soils have larger macropores and absorb water more rapidly than clayey soils. Under low intensity rains, sandy soils produce less runoff than clayey soils. Most of the rain falling on clayey soils is into runoff due to the small micropores, which decrease water infiltration. (Blanco and Lal, 2008). It depends in its calculation on Soil texture as following WEF= (0.37× (Silt +vfsand %)×(0.28 ×Clay %)+14.87)/100 (7) Surface Crust Index-SCF: Soil crust index is inversely proportional to the clay content. The higher the clay content, the lower the soil crust rate and in turn, the lower the degree of protection of the soil surface from the effect of erosion. Crusts are more thick, firm, and strong to erosion than uncrusted soils. The rate at which crusts are degraded depends on the degree of the abrasive forces of the wind. ). It depends in its calculation on soil clay content as following: SCF=1/ (1+0.0049× (CLAY) 2 (8) Lang Factor: Richard Lang established a climate classification based on a ratio factor between precipitation and temperature. The Lang climate factor (L) is calculate using the following formula: L =P/T (9) Where, P: Annual total precipitation (mm), T: Annual temprature mean (C˚).

RESULTS AND DISCUSSION Soil Qaulity Index-SQI
The spatial variation in soil characteristics reflects its sensitivity to desertification and land degradation processes in arid and semiarid regions. Soil characteristics results indicate that P 5 and P 7 had a high sand content, reaching more than 70%. While P 1 , P 2 and P 8 were suffering from salinity, it reached more than 15 dSm -1 in the surface layer of soil. The results indicate that the locations P 6 , P 8 and P 10 suffer from high gypsum content in the soil, reaching 25.00, 11.05 and 9.95%, respectively. The results show that soil quality index ranged between (1.23 and 1.52) as it reached the lowest value at P 3 , which is located within alluvial plain, for plant growth and the highest organic matter content compared to other sites. The highest value is for the fifth pedon, P 5 and P 7 , which have a very fragile structure and loose as a result of the sandy texture, sparse vegetation cover and low organic matter. The indices within the soils of moderate and poor quality, as the result is an interrelated result of many physical, chemical and morphological characteristics. Figures (2) indicate the spatial distribution of the soil quality index, as the percentage of poor soil quality index reached 67%, which includes P5, P6, P7, P8, P10 and other sites fall within the moderate quality, which constitutes 33% of area study.

Fig. 2. Soil Quality Index maps Vegetation Quality Index-VQI Erosion Index:
Soil erosion is one of the most important criteria in evaluating desertification and land degradation, due to detachment soil particles, reduce its fertility, and effect on agricultural crops. The results indicate the variation in the wind soil erodibility, which is related to its calculation on important soil characteristics that have the ability to aggregate soil particles more than 1 mm that increase its resistance. Wind soil erodibility was increased at P 5 and P 7 (0.75 and 0.62), while the decrease in the alluvial plain locations at P 1 , P 2 , and P 3 , which have the good structure, higher organic matter and lower content of sand. According to Dregne (1983) criteria that refer to the effect of wind erosion on soil degradation which classify to Slightly, Moderate, severe and very severe degradation was its area 134.01, 54.78, 18.04 and 8.16 km 2 and as percent(62.33, 25.48, 8.39 and 3.80 )%. The P 7 and P 5 locations, which is suffer from very sever degradation, while most location was at moderate and slightly. The results refer to that locations with high sand content, weak structure and dispersed vegetation cover have higher erodibility to wind erosion. Sandy soils are less cohesive than clayey soils and thus aggregates with high sand content are more easily detached. The results of Figure (3) showed water soil erodibilty ranged between 0.23-0.40 for each of the P 2 and P 5 , respectively. May be relate to the content soils from cementing materials between soil particles, which leads to the formation of large aggregates and a cohesive structure. The soil organic matter is one of the key factors that control the aggregates stability. It physically, chemically, and biologically cement primary particles into aggregates. The soil ability to erosion depends on its structure. Soils with weak soil structure are more detachable. According to figures (3) that indicate the water soil erodibilty, that the location soils of the alluvial plain P 1 , P 2 , and P 3 are the most water erosion range 0.35 -0.39. According to Dregne cretiria, they occurred within lands of degradation The area was severe degradation formed an area of 80.63km 2 and a percentage of 37.50%, while the sites P 5 and P 7 were the least exposed to water erosion because water infiltration is positively correlated with an increase in coarse soil particles and decrease in fine particles (25). Sandy soils have larger macropores and absorb water more rapidly than clayey soils. Macropores conduct water more rapidly than micropores.

Fig.3 A map of wind and water soil erodibility
The results of Figure (4) that the SCF index was relatively high in the sites P5, P6, P7 reached 0.984, 0.984 and 0.799 because weak structure, high gypsum and sand content. According to Dregne (1983) that P 5 and P 7 is within area of Very sever degradation formed 13.81 km2 (6.42) %. While the area of moderate degradation and slightly degradation was 39.66 km 2 and 39.66 km 2 (18.45 and 54.78)%. Thus, the crust is one of the indicators that protect the soil surface from the intensity of winds and raindrops on the occurrence of erosion and its degradation, and this crust depends on the content of the clay. Figure 5 indicates soil erodibilty ranged between 0.016 -0.167 at P 1 and P 5 respectively, and it was found that the sites P5, P6 and P7 had the highest erosion potential (> 0.06) according to Medulas model and it was within the 4 class (very high) which formed an area of 24.16 km 2 (11.24)%. In contrast, P 3 , P 4 , P 8 , and P 10 were within the moderate erodibility, ranging 0.039-0.053, which formed an area of 116.44 km 2 (54.16%). According to Dregne (1983) cretiria, the P 5 , P 6 and P 7 within very severe degradation. As for the sites P 3 , P 4 , P 8 and P 10 , they are within moderate degradation. Thus, wind erosion and soil crust factor have a higher degree of impact than water erosion, which led to the effect of wind erosion in the AL-Jazeera region which suffer from sand dune movement, strong wind, Gypsiferous soil, sandy to loam txture and missmanagement.

Fig. 6. Vegetation green Cover maps VQI-Vegetation Quality Index
According to the obtained data from spatial distribution maps, that the P 9 , P 3 , P 2 , P 1 within the moderate quality, which appears (71.06) km 2 (19.10) %. As for the rest of the pedones, which are P10, P8, P7, P6, P5, with an area of 143.93 km 2 (80.90) % within low quality (Fig.   7). Vegetation cover is one of the most important indicators to monitor of desertification and protect the soil surface from external factors, improves its internal system such as water, air, organic matter, organism activity, soil temperature, humidity, and permeability.

Fig. 7. VQI maps of study area Desertification Environment Sensivitily-(ESAI).
Most of the sites were within the class C and varied according to a subclass and they were within the class C1, which occupied a very small area of 0.22 km2 (0.10)%, and an area under C2 was 54.50 km2 (25.35)%, which included the sites P1, P2, P4 and P9 respectively, where their values were limited range 1.41-1.53. The subclass C3, so it was modified in this study to other classes (C31, C32, C33). Therefore, the sites P5, P6 and P7 were within the higher class C33 environmental sensitivity to desertification, range 1.62-1.68, its area was 34.45 km2(16.03)%, and the area of subclass C32, ranged 1.53-1.56, occupied a large part of the study area, reaching 87.70km2( 40.79)%. In general, the C3 class total area occupied 74.55% of the area of the study area (Figures 8,  9).   compared with other degree, 18.03km 2 for sever degradation (Fig.12).

Fig. 12. Area Leaf Index maps of study area
The OSAVI and GOSAVI vegetation indicators ranged between 0.090 -0.198 and 0.17 -0.29 for the year 2013, and they ranged between 0.10 -0.15 and between 0.14 -0. 22 for the year 2019. This variation in the values of the spectral indices is a result of the influence of soil and atmosphere on the reflectivity of vegetation. The SI5 salinity index ranged between 0.67 -0.89, and the maximum height was reached in soils with high salinity levels such as P 1 , P 2 , and P 8 sites. This may be due to poor management and quality of irrigation water.