SOIL MICRONUTRIENT CONTENT ANALYSIS AND MAPPING OF AGRICULTURAL SALT-AFFECTED SOILS AROUND ABAYA AND CHAMO LAKES, SOUTH ETHIOPIA RIFT VALLEY

. Objective. To analyze the micronutrient content and map the micronutrient fertility status of


INTRODUCTION
Salt-affected soils cause a significant portion of land to become unproductive every year.Soils affected by salt are found all throughout the world, and no continent is exempt from this problem (Basak et al., 2022).Ethiopia's primary challenges are still soil salinity and sodicity in the lowlands and soil acidity in the highlands as a result of the country's reliance on rainfed agriculture (Regassa et al., 2023).Particularly in arid and semiarid areas where irrigation is practiced, soil salinization is becoming more of a problem (Pulido-Bosch et al., 2018).The environment, agricultural ecosystems, and human life are all at risk as a result of the alarming rate at which soil deterioration brought on by saltwater and sodicity is increasing (Prăvălie, 2021).According to reports, salt affects around 11 million hectares of Ethiopia's soil (Borena and Hassen, 2022;Habtamu and Wassie, 2022).The dry and semiarid lowlands as well as the Rift Valley regions of Ethiopia are typically host to naturally salt-affected areas, which are distinguished by increased evapotranspiration rates relative to precipitation (Challa et al., 2022).This problem deleteriously impacts soil fertility, reducing soil productivity (Bisht and Chauhan, 2020).To find solutions for those problems, it is necessary to ascertain the current georeferenced soil micronutrients fertility status ( Barman et al. 2021), irrigation water management techniques, and the chemical and physical characteristics of the soil that cause the problem of salt-affected soils and contribute to that problem (Choukr-Allah et al., 2023;El-Ramady et al., 2022).
Analysis and mapping of soil fertility are necessary to monitor the changes and reveal the state of soil fertility under different soil types and salt-affected soils (Worku et al., 2015).Therefore, in order to better understand soil resources and predict and map soil patterns and distribution more precisely, it is essential to do comprehensive salt-affected soil analysis and mapping soil nutrients status (Brevik et al., 2016).Crop productivity is determined by the status and management of soil nutrients as well as the concentration of nutrients in plant parts that are used for food and feed (El-Ramady et al., 2022).As a result, the state of soil nutrients greatly affects human health.Approximately one-third of arable soils worldwide are deficient in micronutrients, especially zinc (Zn) (Steffan et al., 2018), and human nutrition eventually gets affected by this.Globally, between two and three billion individuals deficiency certain micronutrients; this is particularly the case in developing countries, where at least half of the population is affected (Beal et al., 2017) (Goudia andHash 2015).In sub-Saharan Africa (SSA), the problem of soil micronutrient deficiencies, which frequently affect two to five micronutrients at a time, is pervasive (Ohanenye et al., 2021).Decades of degradation of the soil and the inconsistent and inadequate use of fertilizers, namely nitrogen (N), phosphorus (P), and potassium (K), are the primary causes of this (Rajičić et al., 2020).Although micronutrients have recently been shown to be important for crop productivity, but limited is known about how they relate to nutrition (Tripathi et al., 2015).Plant yield can be affected by micronutrient toxicity and deficiencies (Chrysargyris et al., 2022).
Due to the calcareous nature of the soils, high pH, poor organic matter, salt stress, prolonged drought, high bicarbonate concentration in irrigation water, and imbalances, inadequate nutrition is common in dry land soils (Hailu and Mehari, 2021).The last ten decades' salt-affected soils revealed that, currently, zinc (Zn) insufficiency is the micronutrient that has the greatest negative impact on crop yield (Chhabra and Chhabra, 2021b).A deficiency Fe, Zn, and Mn in the micronutrients that are needed to minimize the toxicity of B and Mo while also neutralizing the pH reaction in the salt-affected soils of Ethiopia's Central Rift Valley (Bedadi et al., 2023).Micronutrient analysis and mapping in agricultural salt-affected soils in Sub-Saharan Africa is crucial for addressing micronutrient deficiencies, optimizing fertilizer use, improving food security and nutrition, enhancing climate resilience, and supporting sustainable land management (Dimkpa et al., 2023;Kebede, 2023).These problems are widespread, exacerbated by salt-affected soils, and have limited resources for smallholder farmers (Sharma and Singh, 2017).Understanding the specific micronutrient limitations of different areas can help farmers apply fertilizers more efficiently, reduce costs, and reduce environmental impact (Bindraban et al., 2020).By addressing these deficiencies, farmers can improve food security, reduce stunting, blindness, and maternal mortality, and build resilience to climate change (da Silva, 2019).
In salt-affected arid and semiarid environments, micronutrient requirements are critical for plant growth.Mangoes need zinc, boron, manganese, and copper for healthy flowering, fruit set, and quality (Chhabra and Chhabra, 2021b).Saline soils can decrease zinc availability, so foliar application or soil amendments rich in zinc may be necessary.Bananas need good levels of zinc, B, Fe, and Mn for growth, disease resistance, and fruit quality (Shahrajabian et al., 2022).Maize needs Zn, Mn, and Fe for enzyme function, photosynthesis, and pollen development.Sweet potatoes need these micronutrients for root development and yield.Cotton requires balanced levels for fiber quality and yield (Pasala et al., 2022).Different vegetables have varying micronutrient needs, and saline soils can affect these micronutrients (Shukla et al., 2018).The Abaya and Chamo Lakes area in the south Ethiopia rift valley is a central agricultural region.However, the soils in this area are highly susceptible to salt accumulation, which can significantly impact crop production.Salt-affected soils can cause several problems for crops.The study of salt-affected soils is a complex and challenging field.Still, it is essential for ensuring sustainable agricultural production in the study area and other regions worldwide.Analyzing and mapping the micronutrient fertility status of the salt-affected soils in this area is essential to developing management options that can decrease salt accumulation and improve the production of crops.The critical and thorough investigation, assessment, and mapping of the micronutrient fertility status of the salt-affected soils in the designated area is essential to the management and exploitation of soil potential.However, baseline information on the nutritional status of the agriculturally salinized soils in the research area must be provided.Therefore, to sustainably produce crops and carry out land use planning, the study's present objective is to investigate the micronutrient levels and map the micronutrient fertility status of agricultural salt-affected soils.

Descriptions of the study location and climate
The Abaya-Chamo sub-basin of the South Ethiopia Rift Valley that splits Ethiopia down the middle in a north-south direction.The basin comprises two lowerlying lakes, Abaya Lake and Chamo Lake (Tiruneh 2005;Walche et al. 2023).The latitude of the study area falls between 5 o 50'00"N and 6 0 10' 0"N, and the Longitude of the study area falls between 37 o 26'0" E and 37 o 40'0" E. The altitude of the study area ranges from 1107 m around Chamo Lake to 1191 m at around Abaya Lake range.Besides this, the altitude of the Institutional University Cooperation (IUC) Project area ranges from 972 m around Abaya and Chamo lakes shores to 3464 m in the highland mountain range (Figure 1).The total area of the four watersheds is 807 km 2 : Elgo (249 km 2 ), Sile (227 km 2 ), Baso (167 km 2 ), and Shafe (164 km 2 ).Elgo and Sile catchments drain Lake Chamo, whereas Baso and Shafe drain Lake Abaya.Of all Abaya-Chamo Lake watersheds, the area around two lower lying lakes, Abaya and Chamo Lakes, are selected for this specific study based on accessibility and the productive potential of the site for crop production and covered a 2019sq.kmarea (Figure 1).The climate around the Abaya and Chamo Lakes basin region is tropical, hot, and semi-arid (Abdi and Gebrekristos, 2022).The bimodal rainfall system in the Abaya-Chamo watersheds seems to be assisted by a humid breeze coming from the Indian Ocean, which is brought in by the inter-tropical convergence zone (ITCZ).Altitude plays a role in the distribution of rainfall.The region experiences short rains in spring (belg) and long rains in summer (kremt), resulting in a bimodal rainfall distribution in most parts of the watershed (Mengistu et al., 2019).In the study area, the rainfall peaks during April and May.On the other hand, the lowest rainfall is recorded during January and February.The temperature is high for three months in the study area.For instance, around Chamo Lake, the temperature increases in February, March, and April, while around Abaya Lakes, the temperature is high during January, February, and March.The mean annual rainfall in the area ranges from 500 to 1100 mm, and the average yearly air temperature is 17-39 °C.According to the AMU-IUC Project 4 (Figure 2), the mean soil temperature ranges from 22 to 35 °C depending on the depth.Agriculture seems to be dominant in the area, with crops such as banana, mango, papaya, maize, cotton, sweet potato, tomato, onion, and haricot beans being cultivated.However, it seems that soil salinity and sodicity are also present in the area.These phenomena are brought on by factors of nature such nearby or nearby water tables, weathering rocks and minerals, low rainfall and high evaporation rates.Unfortunately, these problems are made worse by human actions including inadequate irrigation, deforestation, and overgrazing of livestock (Tessema et al., 2023).

Method of Sampling and Sample Collection
A reconnaissance study was carried out prior to the collection of samples in order to determine the degree of soil variability or homogeneity based on differences in physiography, land use, and visually detectable soil properties (soil texture, drainage condition, and salt crust at the soil surface, among other things).It was decided what sampling technique and sample size were needed to adequately represent the study area.The research area's topographic map (scale 1:50,000) and reconnaissance survey data were used to identify sampling places and points, which were then categorized into five map units.In order to prepare composite soil samples from the obtained soil samples, three representative soil sampling regions were chosen from each map unit and homogenized.For this investigation, 300 auger soil samples were obtained, as 10 auger soil samples were needed to make one composite soil sample.Rearranging the sampling depth will lead to surface (0-20 cm) and subsurface (>20 cm) samples for saline or saline-alkali soils (Wogi et al., 2021).Then, with two depths (0-20cm and 20-40cm) using a systematic sampling technique, with a 600m sampling interval, 30 soil samples were used to analyze soil micronutrient status and mapping since the study area is salt-affected according to Walche et al. (2023).The soil micronutrient state in the research area was mapped using just the analytical results from surface soil samples.The auger took enough subsamples, depending on the location of each sampling unit and the level of micro-variability present.Any alien items, such stones and plant leftovers, were thrown away while collecting samples.We won't sample in areas that are close to trees or that have certain characteristics like compost pits, moist areas, or old manures.Every sampling place had a georeferenced, and the dates of the samples were accurately recorded.Each composite soil sample weighed about one kilogram before being packaged, labeled, and delivered to the laboratory for analysis.Abaya Lake Area RF Chamo Lake Area RF Abaya Lake Area Tmax Abaya Lake Area Tmin Chamo Lake Area Tmax Chamo Lake Area Tmin

Soil Sample Preparation and Laboratory Analysis
Soil samples from the field were air-dried at a suitable laboratory temperature of 24°C.After drying, the soil samples were crushed using a mortar and pestle and passed through a 2-mm mesh sieve for laboratory analysis.Subsequently, the soil samples underwent standard laboratory procedures to determine micronutrient content.The Ethiopia Design and Water Works soil laboratory performed laboratory analyses.The Diethylene Triamine Penta Acetic acid (DTPA) method was used for analyzing the soils' DTPA extractable micronutrient content (Fe, Mn, Zn, and Cu) (Lindsay and Norvell, 1978).Five grams of airdried soil were centrifuged for 15 minutes at 3000 rpm after being mixed for three hours with 20 ml of DTPA, Tri-Ethanol-Amine, and calcium chloride combination solution.Whitman No. 42 paper was used to filter the supernatant into a 50 ml volumetric flask.An atomic absorption spectrophotometer was then used to measure the amount of available micronutrients in the filtrate (Lindsay and Norvell, 1978).

Geostatistical analysis and Mapping of Soil Micronutrients
When samples were taken, GPS pinpointed their exact locations.Following that, the research area was defined and divided into mapping units.The whole area of the study location as well as the Easting and Northing coordinates of each map unit were carefully recorded.The combination and final computation of intermediate surfaces based on the combination decision rule and basic questions were performed using the Raster Algebra analysis capabilities of the Spatial Analyst extension.Based on the findings and ratings of soil laboratory analyses, the area of each map unit was also rated (very low, low, medium, high, and very high).Lastly, a map of the research area's soil micromutrients status was created.The accuracy of the interpolation techniques was evaluated via crossvalidation using mean error (ME), root mean square standardized error (RMSSE), and root means square error (RMSE) (Arétouyap et al., 2016).Selecting the best-fitted semivariogram model for an interpolation map could be made easier by values of the mean error (ME) and root mean square standardized error (RMSSE) being closer to 0 and 1, respectively, indicating that the prediction values were close to the measured values (Ferreira et al., 2015).

Data Analysis
Descriptive statistics data were analyzed using SAS software, version 9.4 (Blanca Mena et al., 2017).The rating of determined values was based on a guide to standardized analytical methodologies for soil data (Wogi et al., 2021).Nutrient variability was determined using the coefficient of variation.The variability is low when the CV is ˂ 10%, moderate between 10 and 100%, and strong when ˃ 100% (Terefe et al., 2021).The laboratory results were imported into a GIS environment to determine the geographical distribution of soil micronutreint status in the investigated area.The data were entered into Microsoft Excel with their corresponding coordinates (Latitude and Longitude).Spatial prediction and mapping of the un-sampled surface from laboratory point data were done in a GIS environment using interpolation techniques.From laboratory point data, the un-sampled surface was predicted and mapped using the standard kriging method in Arc GIS 10.81 software.

Geostatistical analysis and Mapping of Soil Micronutients status
Table 1 displays the findings of the soil spatial analysis.The ratio of nuggets to sill or spatial dependence Co/(Co + C) is the spatial property definition.When the value of Co/(Co + C) is less than 0.25, the variable is said to have a strong spatial dependency; when it is between 0.25 and 0.75, it is considered to have a moderate geographic dependence; and when it exceeds 0.75, it is considered to have a weak spatial dependence (Addis et al., 2015;Cambardella et al., 1994;Sani et al., 2023).The semivariogram produced by the geostatistical analysis is displayed in Table 1 and provides various models of the soil characteristics' spatial distribution and degrees of spatial dependency.Semivariance demonstrated that the spatial dependence of soil parameters was the same (Cambardella et al., 1994;López-Granados et al., 2002) (Table 1).According to Cambardella et al. (1994), for all soil micronutrient characteristics investigated, a considerable geographical dependence was seen in the nugget/sill ratio (C0/C0 + C) <25%, which reveals strong spatial dependence.The model explained the distribution's results by demonstrating how natural factors mostly of a geological nature affect the data.This may be primarily caused by intrinsic or inherent causes of variability (e.g., terrain, parent materials, and variations in soil texture) (Addise et al., 2022;Stritih, 2021).Similarly, Saleh (2018) and Corwin and Yemoto (2020) also reported that strong spatial dependence of soil properties is associated with intrinsic structural factors like parent material, texture, climate, and topography; weak spatial dependency is associated with extrinsic factors that are random, like soil management practices like fertilization and plowing (Gülser et al., 2016); conversely, a moderate degree of spatial dependence is probably influenced by both extrinsic and intrinsic factors (Swafo and Dlamini, 2023).For soil Fe, the nugget effect was commonly higher (Table 1).This suggested that regional heterogeneity in soil qualities existed at short distances.The spatial variability at smaller distances than the minimum separation between measurements is associated with the nugget effect (Yao et al., 2020).The Spherical model was the highest accuracy among the other experimental semivariogram models for estimating all of the studied soil micronutrients for the agricultural salt-affected soils around Abaya and Chamo Lakes, South Ethiopia Rift Valley.The spatial range values for all investigated soil properties ranged from 4,615 m to 20,924 m, as shown in Table 1.Since this range is larger than the average sampling distance of 600 m, the sampling interval used in this study was adequate to capture the spatial variability in the investigated soil properties.

Available Iron
Iron is a crucial micronutrient for plants' various metabolic processes throughout their life cycle (Rout and Sahoo, 2015;Tripathi et al., 2015).The South Ethiopian Rift Valley's agriculturally salt-affected soils near Abaya and Chamo Lakes have very high levels of available iron.In the surface soil (0-20 cm depth), the amount of iron was 14.54-176.02mg kg -1 ; in the subsurface soil (20-40 cm depth), it was 13.99-57.51mg kg -1 .The mean quantity of available iron in the soil is 61.78 mg kg -1 in surface soil and 25.79 mg kg -1 in subsurface soil (Table 2).This goes above the very high threshold set by Wogi et al. (2021) of 50 mg kg -1 (Figure 3).These soils' high pH may be responsible for their high available iron level (Shanshan et al., 2021).Alkaline soils, frequently affected by salt, can bind iron in the soil and reduce its availability to plants.However, iron availability in these soils doesn't seem to be the high pH (Martínez-Cortijo and Ruiz-Canales, 2018).The nature of saltaffected soil has waterlogging and can increase the available iron content in salt-affected sodic soils (Chhabra and Chhabra, 2021).This is because waterlogging can displace the sodium ions that are bound to the iron in the soil, making the iron more available to plants.Waterlogging can displace the sodium ions from the soil, freeing up the iron.This makes the iron more available to plants, which can help to improve their iron status (Rengel, 2023).Generally, an important factor influencing the amount of soluble Fe in the soil solution is the oxidationreduction process.But in the case of waterlogged fallow it has less influence since lowering redox reaction increases Fe 2+ solubility (Wang, 2022).In soils, there is very low Fe 3+ in the solution.The concentration of Fe 2+ in solution is lower in welldrained, oxidized soils than it is in the dominating Fe 3+ species in solution.Soluble Fe 2+ increase significantly when the soil become waterlogged (Hewitt et al., 2021;Kögel-Knabner et al., 2010).The available iron coefficient of variation was rated strong surface soil due to CV% greater than 100CV% while moderate for subsurface soils since it is between the 10 to 100 CV% range.The high level of iron present in the soil of the study area is great news for the farmers in the region.This indicates that their crops will have access to sufficient iron, which is essential for their growth and development.However, it's important to note that too much iron can also be harmful to plants.Therefore, it's advisable for farmers to periodically test their soil to ensure that the iron level is optimal for their crops (Rehman et al., 2021;Rout and Sahoo, 2015;White and Broadley, 2009;Willy et al., 2019).

Available Manganese
Manganese is a vital micronutrient for plants, playing a key role in many metabolic processes as an antioxidant cofactor for enzymes and in photosynthetic processes (Kwakye and Kadyampakeni, 2022).The available Manganese ranged from 17.95 to 79.44 mg kg -1 in the surface soil (0-20 cm depth) and from 13.98 to 45.37 mg kg -1 in the subsurface soil (20-40 cm depth) (Table 2).The available manganese level in the agricultural saltaffected soils near Abaya and Chamo Lakes in South Ethiopia Rift Valley is very high.The mean available manganese level in the surface soil is 32.08 mg kg -1 and in the subsurface soil is 23.53 mg kg -1 (Table 2).The high level of available manganese in these soils is likely due to the high salinity of the soils.Salinity can  increase the availability of manganese by displacing it from the soil particles.This can lead to manganese toxicity in plants, which can manifest as stunted growth, chlorosis, and necrosis (Bhatla et al., 2018).The soil quality standards and interpreting guidelines developed by Wogi et al. (2021) define a very high level of available manganese as > 6mg kg -1 (Figure 3).Its coefficient of variation was rated moderate for both surface and subsurface soils since it is between the 10 to 100 CV% range (Table 2).These are most likely manganese under waterlogged saltaffected soil, typical fermentation byproducts.This microbial metabolic process occurs when oxygen levels are very low and degrades humus into simpler organic compounds while producing H2 and CO2.In the soil solution, the reported concentrations of acetate (millimolar) and H2 gas (micromolar) are typical of active fermentation (Nivethadevi et al., 2021;Steger et al., 2017;Thampatti, 2022).The accumulation of these fermentation products during the initial stages of incubation is followed by their depletion as Mn (II) levels rise or methane production starts, indicating consumption by the microbial community during these stages (Huan et al., 2018).Soil waterlogging will reduce O2 and reduce redox potential, increasing soluble Mn 2+ .Mn availability can be increased by poor aeration in compacted soils and by local accumulation of CO2 around roots and other soil microsites (Jennings, 2007).The resulting low redox condition will render Mn more available without appreciably affecting the redox potential of the pH of the bulk soil.So, the general manganese level in these soils is not quite at the toxic level, but it is getting close (Maguffin et al., 2020).The high level of readily available manganese must recognized, and measures must be taken to reduce the possibility of toxicity.The two potential remedies are altering the crop variety to one that can tolerate manganese toxicity or adding chelating agents to the soil to bind the manganese (Dhaliwal et al., 2023;Neal and Zheng, 2015).

Available Zinc
Zinc deficiency is an important micronutrient barrier to food production in every region of the world, and its application has been successful in almost all crops (Younas et al., 2023).The amount of readily available zinc in the surface soil (0-20 cm depth) ranged from 0.63-1.04mg kg -1 , and in the subsurface soil (20-40 cm depth), it ranged from 0.08-0.99mg kg -1 (Table 2).
There is low readily available zinc in the agricultural salt-affected soils close to Abaya and Chamo Lakes in the South Ethiopia Rift Valley.The mean concentration of available zinc in soil is 0.80 mg kg -1 in surface soil and 0.55 mg kg -1 in subsurface soil.According to Mantovi et al. (2003), the normal range for zinc in the soil is 1.5 to 6 mg kg -1 .These soils' high salinity is probably the reason for their low concentration of readily available zinc.Zinc can form insoluble compounds by reacting with carbonate and hydroxide ions in soils with high pH levels.This can lead to a reduction in plant availability of zinc.Soil salinity can also limit zinc availability by decreasing microbial activity, which is responsible for releasing zinc from organic matter (Andrunik et al., 2020;Baruah, 2018;Suganya et al., 2020).By attaching zinc to soil particles, salinity can reduce zinc availability (Acosta et al., 2011).Zn 2+ and soil organic matter (OM) components also form stable complexes.Zn availability will be decreased during immobilization reactions; this happens in soils with humic peat deficiencies.These may be why a soil with a healthy amount of organic matter has a zinc deficiency (Laurent et al., 2020;Suganya et al., 2020).On the other hand, keeping Zn 2+ in solution will improve availability by forming soluble chelated Zn compounds.Freshly applied organic matter and its constituents can chelate Zn 2+ , though this ability is not always reflected in improved Zn uptake by plants.
Plants lacking zinc can suffer from stunted growth, yellowing of the leaves, and decreased yields (Alloway, 2013;Kayranli, 2021).According to the soil quality standards and interpretation guidelines developed by Wogi et al. (2021), a low level of available zinc is less than 1.0 mg kg -1 , hence the study area rated low (Figure 3).Therefore, these soils have a significantly lower level of zinc availability than is advised.It is critical to be aware of the limited zinc supply and to take precautions against deficiency.This might involve applying fertilizer with zinc to the soil or using a cover crop that resolves zinc (Mustafa et al., 2022).The coefficient of variation of available zinc was rated moderate for both surface and subsurface soils since it is between the 10 to 100 CV% range (Table 2).

Available Copper
Copper is a crucial micronutrient for the growth and development of plants, but it may also be toxic (Ali et al., 2020).In the surface soil (0-20 cm depth), the amount of copper that was readily available ranged from 3.19 to 10.88 mg kg -1 , and in the subsurface soil (20-40 cm depth), it ranged from 2.21 to 6.85 mg kg - 1 .Near the salt-affected agricultural soils of the South Ethiopian Rift Valley's Abaya and Chamo Lakes, there is a readily available and very high concentration of copper.The surface soil (0-20 cm depth) and the subsurface soil (20-40 cm depth) have mean available copper levels of 5.22 mg kg -1 and 3.82 mg kg -1 , respectively (Table 2).The high concentration of copper in the agricultural salt-affected soils in the study area could be attributed to the abundance of copper-rich volcanic rocks in the region due to its volcanic origin (Hua et al., 2021).Additionally, the alkaline nature of the soils and their high clay content create favorable conditions for the retention of copper in the soil (Kome et al., 2019).Over time, copper is gradually released from these rocks through weathering and leaching and builds up in the soil, leading to high levels of available copper that can cause harm to animals, humans, and plants (Hough, 2010;Izydorczyk et al., 2021).In most soils, the copper content ranges from 2 to 100 mg kg -1 , with an average value of about 30 mg kg -1 , so this value falls within the normal range (Panagos et al., 2018).According to Bhatla et al. (2018), most of this is in unavailable mineral form.It may pollute water bodies as well.Following the standards and interpretation guidelines, Wogi et al. (2021) developed a very high available copper level greater than 3 mg kg -1 (Figure 3).There are various ways to reduce the quantity of available copper in the soil.One of the ways is to remove the copper-rich rocks in the region.Another option is to add organic matter to the soil, which helps to bind the copper and decrease its availability to plants and animals.It is crucial to monitor the amount of available copper in the soil and take necessary measures to reduce it.The high level of readily available copper can pose a significant risk to the environment and can have a negative impact on agriculture (Alengebawy et al., 2021;Tóth et al., 2016;Van der Ent and Reeves, 2015;Vinod et al., 2021).The available copper coefficient of variation was deemed moderate for both surface and subsurface soils due to its value falling within the range of 10 to 100 CV% (Table 2).

CONCLUSION
Soil properties and distribution are crucial for developing soil health and fertility management plans, as soil fertility decreases due to salinity and sodicity, impacting essential micronutrient solubility.The study aims to analyze salt-affected soils' micronutrient content and map fertility status for successful crop production, land use planning, and reclaiming saltaffected soils.The study found high levels of available iron, manganese, and copper in the soils, while zinc was low.For soil with Fe available, the nugget effect was commonly higher; this suggested that regional heterogeneity in soil qualities existed at short distances while the rest of the micronutrient regional heterogeneity existed at long distances.The available iron coefficient of variation was rated strong surface soil while moderate for subsurface soils.Meanwhile, the available copper, manganese, and zinc coefficients of variation were deemed moderate for both surface and subsurface soils.The study recommends incorporating organic matter into the soil to enhance its structure, water retention, nutrient availability, and reclamation by using different reclaiming materials for salt-affected soils.The study area predominantly has low zinc fertilizer levels, suggesting low soil zinc availability for plants, but they may still require additional zinc fertilizer for optimal yield.On the other hand, very high micronutrient contents must be managed to reduce their toxicity on plant growth and human life.

Figure 1 .
Figure 1.Location map of the project area and the study area.

Figure 3 .
Figure 3. Soil micromutrients map of agricultural salt-affected soils around Abaya and Chamo Lakes.