Using Geospatial Technologies to Separate Soil Units and Predict Some of Their Characteristics in Basra Governorate (Indices)

This study was conducted to classify the soils of eastern Basra Governorate, southern Iraq, within the administrative borders of Abu Al-Khasib District extending south to Al-Faw District, using remote sensing techniques and geographic information systems. The soil units were separated by adopting remote sensing technology through the use of satellite image from Landsat8, the TIRS - OLI sensor (The Operational Land Imager), and spectral indices with field observations. A map of the soil units was prepared using the GIS program. Eight locations of soil pedons were identified, and they were divided The study area is divided into two paths, and each path contains four typical pedons within the boundaries of the study area as follows:


INTRODUCTION
Soil, with all its types, is one of the basic elements and components of vegetation cover and agricultural production.This research is concerned with studying soil as an important element in soil survey and classification studies and as a product of natural, climatic and biological factors.Soil is one of the natural resources that leads to achieving full benefit when exploited and requires the application of scientific methods and procedures.Modern methods that help achieve sustainable agricultural production.At the forefront of these methods is implementing soil survey work on a large scale, giving the necessary recommendations on how to use and maintain soil units, and determining the suitability of each soil unit for various purposes, especially agricultural ones (Al-Ani 2006) .Remote sensing and geographic information systems are considered the main means of surveying and monitoring land resources, identifying their 2 distribution and characteristics, and preparing plans and programs to achieve development.It is an important source of data that provides information efficiently and effectively that traditional methods cannot provide.What we are witnessing today in the information age is the huge amount of data that requires effective devices to deal with it.Correct, accurate information based on scientific analysis leads to the optimal and sustainable use of earth's resources.The spectral reflectivity of soil is essential for many remote sensing applications, as it depends on the physical and chemical properties of the soil, and based on the quantity and quality of electromagnetic radiation reflected from the soil surface within multiple spectral bands, different types of soil can be characterized and isolated (Lillesand and Kiefer, 1999) .Indices is one of the most important improvements applied to satellite image, and this is of great importance in transforming the spectral properties of visual appearances affected by luminosity.indices is widely used in mineral investigation, plant analysis, desertification, and environmental monitoring.Its importance lies in many cases, as the indices is the best at distinguishing differences that cannot be observed in images with basic color bands, as well as reducing the effect of shadows in multispectral images.Indices is widely used in agricultural and environmental studies due to its relationship to the growth cycle of plants, soil properties, and soil moisture.It is one of the methods for improving the spectral information of satellite data by distinguishing barren soils, vegetative cover, and wet soils, and determining degrees of desertification and drought, as well as providing important information about the soil and plants for uses.agricultural (Zinck, 2008) .This study aimed to separate soil units based on the variation in spectral reflectances and Indices of the Earth's surface and to study the spatial variations of some indices in the study area.

-Study Area
The study area was chosen, which is part of the alluvial plain that contains sediments belonging to the Shatt al-Arab and Karun rivers.The soil of this area is characterized by the fact that it has a calcareous sedimentary source material that belongs to the newly formed soil class, Entisols.The study area is located east of Basra Governorate, southern Iraq, within the administrative borders of Abu Al-Khasib District, extending south to Al-Faw District.It is bordered to the east by the Shatt Al-Arab River and is located between longitudes 48°1'28.56"-48°31'25.08"north and latitudes 29°.57'48.98"-30°26'24.51"east, with an area of 874,405 km 2 , as shown in Figure 1. 8 locations were identified to dig typical pedons and projected them on the map using a GPS device and the Universal System UTM.

-Field and office work 2-1: Surveying the soil and determining the location of the pedons
The study area was visited in the field several times during the period 10/15/2022 until 12/15/2022 with the aim of determining the locations of the pedons for the study area.The study area was surveyed in a semidetailed manner based on satellite image for the year 2022, as it was noted that most of the areas are not agriculturally exploited and are Abandoned lands, with the exception of some lands along the Shatt al-Arab River.Correction operations were carried out on the satellite image, converting it into a digital image, then The first stripe: This stripe represents the soil unit belonging to the river levees, extending from the Sihan district of Abi al-Khasib district to the Ma'amir district of al-Faw district, represented by pedons 1, 3, 5 and 7, respectively.pedon 7 is located in the Sayhan area, pedon 5 is located in the Siba district, pedon 3 is located in the Al-Bahar district, and pedon 1 is located in the Ma'amer district .
The second stripe: This stripe represents the soil unit belonging to the river basin, which extends from the Sayhan district of Abu Al-Khasib district to the Ma'amer district of Al-Faw district, which is represented by pedons 2, 4, 6 and 8, respectively.pedon 8 is located in the area adjacent to the Sayhan area, pedon 6 is located in the area adjacent to Al-Sibah sub-district, while pedon 4 is located in the area adjacent to Al-Bahar sub-district, pedon 2 is located in the area adjacent to Al-Ma'amer sub-district .

-2: Field procedures
After separating the soil units (Figures 2 and 3) in the study area and determining the locations of 8 pedons distributed within it, a GPS device was used to determine the locations of the pedons and projected them on the map.Information about the soil of the study area was documented in the field, and location information for each of them was recorded, which included both vegetation cover.Land uses and site characteristics (Soil Survey Staff, 2003) .The satellite image captured by the Landsat8 satellite, the TIRS -OLI (The Operational Land Imager) sensor, which had eleven spectral bands on September 16, 2022, with a resolution of 30 m, was used, while the eighth band had a resolution of 15 m.The satellite image was used to obtain classification maps( unsupervised and supervised) and indices maps .

-4: Digital processing of Satellite image
The digital processing of the satellite image was done using the computer program Arc map 10.4.1.The spectral bands that have the highest Optimum Index Factor (OIF) were chosen as they are more capable of expressing the difference that were adopted to extract the appropriate combination.The false color combination was chosen for spectral bands 7, 5, and 3 for RGB colors, respectively, to form the best color combination to distinguish the soil of the study area, since these bands are specialized in soil and mineral studies (Faleh and Shawan, 2012) .

-5: Indices
A set of indices were used, including the Normalized Difference Vegetation Index (NDVI) proposed by (Rouse et al., 1974), equation ( 1), and the Bare Soil Index (BSI) proposed by Jamalabad and Abkar (2004).Equation ( 2 The results in Table 1 and Figure 4 indicate that there is a state of variation in the values of the Change in Vegetative Cover Index (NDVI) between the pedons of the study area, as the values of the index ranged between < 0 -0.79, and this represents the state of variation in the vegetation cover.The closer these values are to 1.0 This means the presence of dense vegetation cover.Values less than 0.1 represent abandoned and barren soils devoid of vegetation and residential areas, while values ranging between 0.1 -0.4 indicate the presence of shrubs and grass, while values higher than 0.4 indicate dense plants such as trees.(Rouse et al,. 1974).The results showed that the highest value of the vegetative index in the first path was that these groves were located in the area of river levees with vegetation cover, with the presence of some trees scattered, while barren and abandoned soils prevailed in the rest of the groves of the study area.Therefore, this indices can be used in diagnosing the vegetative cover.Which was based on the ratio between the spectral reflectivity values of the infrared band and the red band that is suitable for this purpose, and then these values appeared very low, and this is an indicator of weak agricultural investment in the study area (Kadhim et al,. 2020) .
/© 2024 The Authors.Published by Academic Journal INC.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/) -publishing.com2833-5376 /© 2024 The Authors.Published by Academic Journal INC.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/) 3 separating it into categories based on spectral reflectivity to obtain an undirected image, Figure 2, and then converting it to a directed image, Figure 3, with spectral bands 7. 5 and 3 to create the best color combination to distinguish the soil of the study area, since these packages are specialized in soil and mineral studies (Faleh and Shawan, 2012).The study area was divided into two stripes, and each stripe contains four pedons within the boundaries of the study area.These paths are sequentially as follows: -publishing.com2833-5376 /© 2024 The Authors.Published by Academic Journal INC.This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/) 5