TIGRAY ESIA CHARACTERISTICS

INTRODUCTION

The purpose of this Chapter is to describe the receiving environment in terms of within the Project site and surrounding area, to establish the extent to which agricultural soils will be removed from the site as a result of the proposed Tigray IAIP and RTC site developments and to identify potential risks to the identified soils and recommend associated mitigation measures. This was established by undertaking a fertility analysis of the soils sampled at the sites and calculating the potential risks that the proposed development will pose to the soils, with and without mitigation measures being put in place. The description provided in this chapter is based on primary data obtained from site investigations.

AIMS AND OBJECTIVES

The main aims of the soils investigation within this overarching study are threefold: 1. To establish the agricultural value of the soils to be removed in order for the proposed Tigray IAIP and its associated RTC to be built; 2. To establish the main soil-associated risks identified as a result of the proposed project, and 3. To identify potential mitigation measures associated with these risks.

METHODOLOGY

DESKTOP ASSESSMENT

A detailed desktop assessment was undertaken for the Tigray IAIP and RTC sites. This included assessing the ISRIC World Soils Database, based on the World Reference Base Classification System (WRB, 2006) in order to establish the soil types according to an international standard system. Information associated with the outcomes of the ISRIC world soils database outcomes was reviewed, as was general information associated with Ethiopian soils, and, specifically, those found in the Tigray region.

SITE ASSESSMENT

Site visits were conducted from the 28th to 31st August 2017 at the Tigray IAIP and RTC sites. , classification, field mapping and sample analysis were undertaken. Six soil samples were taken at the IAIP site and two soil samples were taken at the RTC site. The following steps were performed: 1. Survey of the study area was undertaken on foot, using a hand-held bucket auger to identify soil forms present. Current activities at the site were also noted, and specific areas of land use and infrastructure were noted. 2. Auger points were assessed to a depth of approximately 1.5m for classification purposes, roughly according to a pre-determined set of points (see Figures 1 and 2) drawn along zig- zagged transects. Free survey was undertaken using the points as a guideline. 3. A hand-held GPS was used to record the location of each auger point. 4. Soil forms were described in the field according to local soil characteristics, the World Reference Base classification system (WRB, 2006) and the South African Taxonomic System (Soil Classification Working Group, 1991), published as a Memoir on the Agricultural Natural Resources of South Africa No.15; 5. Representative soil samples were collected and submitted to Jones Laboratory in Wales for analysis. Samples were analysed for Total Nitrogen, Calcium, Magnesium, Potassium, Copper, Iron, Aluminium, Manganese, Molybdenum, Zinc, Phosphorus, Boron, Total Sulphur, soluble Chloride, pH, Total Organic Carbon, Available Phosphorus and pH and the particle size distribution was determined. The general guidelines for interpreting results developed by Horneck et al. (2011) was followed in interpreting the soils analysis results for the Tigray IAIP and RTC Sites; and 6. The typical land uses and their associated soils were investigated for the Tigray region and the land uses identified on site were noted and mapped.

SOIL CLASSIFICATION

WORLD REFERENCE BASE CLASSIFICATION SYSTEM

The World Reference Base for Soil Resources (WRB, 2006) is the international standard taxonomic soil classification system endorsed by the International Union of Soil Sciences (IUSS). It was developed by an international collaboration coordinated by the International Soil Reference and Information Centre (ISRIC) and sponsored by the IUSS and the FAO via its Land & Water Development division. It replaces the previous FAO soil classification. The WRB borrows heavily from modern soil classification concepts, including USDA soil taxonomy, the legend for the FAO of the World 1988, the Référentiel Pédologique and Russian concepts. The classification is based mainly on as an expression of paedogenesis. A major characteristic the USDA soil taxonomy system is that climate is not part of the system, except insofar as climate influences soil profile characteristics. As far as possible, diagnostic criteria match those of existing systems, so that correlation with national and previous international systems is as straightforward as possible. The WRB is meant for correlation of national and local systems.

ETHIOPIAN CLASSIFICATION SYSTEM

No Ethiopian classification system was identified through local partners, local university enquiries and literature searches. Soils papers published in Ethiopian journals utilise the FAO or WRB classification system (depending on when they were written) as these systems are widely used throughout Ethiopia (Assefa, 2002; Mishra et al., 2004; Ayalew, 2015).

SOUTH AFRICAN CLASSIFICATION SYSTEM

The soils identified in the field were classified by form in accordance with the South African soil taxonomic system (Soil Classification Working Group, 1991) as a great deal of information is available about the various South African soil forms. In this way, more information could be given about the characteristics of the types of soils identified in the field. All South African soil forms fall within 12 soil types; Duplex (marked accumulation of in the B horizon), Humic (intensely weathered, low base status, exceptional humus accumulation), Vertic (swelling, cracking, high activity clay), Melanic (dark, structured, high base status), Silicic (Silica precipitates as a dorbank horizon), Calcic (accumulation of limestone as a horizon), Organic (peaty soils where water inhibits organic breakdown), Podzolic (humic layer forms beneath an Ae or E), Plinthic (fluctuating water table causes iron re-precipitation as ferricrete), Oxidic (iron oxides weather and colour soils), Hydromorphic (reduced lower horizons) and Inceptic (young soils - accumulation of unconsolidated material, rocky B or disturbed) soils.

SOIL CAPABILITY ASSESSMENT

The area’s soils capability was assessed and mapped, based on the results of the classification study and the sample results. The South African land capability classification system by Scotney et al. (1987) was used to identify and map land capability and soil potential (Table 0-1). This system is useful in that it is able to quickly give one an overview of the agricultural capability and limitations of the soils in question, and is useful for soil capability comparisons. Criticisms of this system, however, include its lack of consideration of the local setting, land use planning and a lack of financial resources (Nethononda et al., 2014). For this reason the site’s soil capability has also been assessed taking the local setting into account. Table 0-1: Land Capability Classification System (Scotney et al., 2014)

BASELINE ENVIRONMENT

REGIONAL OVERVIEW

According to the World Reference Base for Soil Resources (WRB, 2006), the soils of Ethiopia can be classified into five principal types. The first type is composed of Nitosols and and is found on portions of the Western and Eastern highlands. These soils are formed from volcanic material and, with proper management, have medium to high potential for rain-fed agriculture. The second group of soils; and Luvisols, are found in the Simien plateau of the Western Highlands. They are highly weathered with a subsurface accumulation of clay and are characterized by low nutrient retention, surface crusting, and hazards. With proper management, they are of medium agricultural potential. The third group of soils is the dark clay found in the Western Lowlands and at the foothills of the Western Highlands. Composed of , they have medium to high potential for both food and agriculture but pose tillage problems because they harden when dry and become sticky when wet. Some of the rich coffee-growing regions of Ethiopia are found on these soils. The fourth group is composed of Yermosols, Xerosols and other saline soils that cover desert areas of the Eastern Lowlands and the Denakil Plain. Because of moisture deficiency and coarse texture, they lack potential for rain-fed agriculture. However, the wetter margins are excellent for livestock, and even the drier margins respond well to irrigation. The fifth soil group is Lithosols found primarily in the Denakil Plain. Lack of moisture and shallow profile preclude cultivation of these soils. Of the 25 World Reference Base/FAO soil orders, 17 exist in Ethiopia. Lithosols, Cambisols, Nitosols, Vertisols, Xerosols, , and Luvisols cover more than 80% of the country, and are the most important soils. Vertisols are very important soils in Ethiopian agriculture. According to the WRB Reference Soil Group (2006), Luvisols, and dominate the Tigray IAIP and RTC sites TIGRAY IAIP

DESKTOP REVIEW

As mentioned, the ISRIC database shows that the Tigray IAIP site to be dominated by Luvisols, Alisols and Retisols. The combination of Luvisols, Alisols and Retisols works out at an average particle size distribution over the site of 45% , 21% and 34% clay. Using the United States Department of Agriculture Triangle (USDA, 1939), which is widely used world-wide, the soil of the site would, on average, be classified as a Sandy Clay (USDA, 1939). The mixed mineralogy, high nutrient content, and good drainage of Luvisols make them suitable for a wide range of agriculture, from grains to orchards to vineyards. Luvisols form on flat or gently sloping landscapes under climatic regimes that range from cool temperate to warm Mediterranean. Luvisols are technically characterized by a surface accumulation of humus overlying an extensively leached layer that is nearly devoid of clay and iron-bearing minerals. Below the latter lies a layer of mixed clay accumulation that has high levels of available nutrient ions comprising calcium, magnesium, sodium, or potassium. These soils often differ from other types of soils in the amount of Calcium (Ca) present in the parent material (J.A. Williams, 1990; Ebelhar et al, 2016). Retisols are similar to Luvisols in that they have a clay illuviation horizon, but also contain a bleached, coarser-textured soil material into the illuviation horizon forming a net-like pattern (FAO, 1998). Alisols are strongly acid, generally unproductive soils, with accumulated high activity clays in their . Aluminium (Al) dominates the exchange complex (FAO, 2001) and they are poorly drained soils with a dense subsurface clay layer, which causes a relatively high concentration of Al ions in the root zone. Alisols occur mainly in tropical and humid subtropical climates. Alisols’ high acidity is increased by limited drainage and they thus need liming. They contain few nutrients and therefore need fertilizer, and do not have much surface coherence so are easily eroded. Al and Manganese (Mn) toxicity is a very serious problem in Alisols, because at the low pH of these soils, such generally insoluble metals become soluble and can poison plants. Oil palm, cotton, and maize are crops suitable to be grown on Alisols, though most crops require very intensive fertilisation for long-term success (Dahlgren et al., 2016). According to the preliminary geotechnical assessment undertaken for the Tigray study (Mahindra, 2016), both the Tigray IAIP and RTC sites comprised soils that consist of black, soft to medium stiff, highly plastic, silty clay with traces of sand.

LAND USE ASSESSMENT

At the Tigray IAIP site, 100% of the area is used for crop production. This can be seen in Figure 3.

SOIL CLASSIFICATION

WITBANK / SOILS In most soil classification systems, a soil name exists to describe soils that have been modified such that they do not resemble their original . These soils can include those that have been used for agriculture where ploughing has modified the soil. For the purposes of this study, where previously ploughed soils are clearly identifiable (and ploughing is generally not deep in the area), these have been treated as their original soil type, so, while some of the soils identified could technically be classified as modified soils, the original soil forms could always be identified, so were used instead to make the outcomes of the study more useful. In the South African soil classification system, the closest soil form to a type of soil that has been formed or heavily modified due to long-term human activity is called a Witbank, which is an Orthic A horizon over man-made deposits. An Anthrosol in the World Reference Base for Soil Resources is a type of soil that has been formed or heavily modified due to long-term human activity, such as from irrigation, addition of organic waste or wet-field cultivation used to create paddy fields. Such soils can be formed from any parent soil, and are commonly found in areas where agriculture has been practised for centuries. can be found worldwide. The Witbank and Anthrosol soils thus both describe soils that have been modified through anthropogenic processes.

MILKWOOD / LEPTOSOL SOILS Soils that could be described as Milkwood soils in the South African classification system were identified over 135ha or 52% of the IAIP site (see Figure 4). This soil is characterised by a Melanic A horizon over hard rock. Photograph 1 was taken during the soil survey, and shows the dark Melanic A horizon around the auger hole, and the gravelly hard rock on the plastic sheet. The Milkwood soil form falls into the South African Melanic soil group. These dark coloured, strongly structured, high base status soils are similar to the dark Vertic soils but are physically more subdued for textural or mineralogical reasons (Fey, 2010). The Milkwood soil form is similar to the WRB Leptosols soil group (Fey, 2010). Leptosols are soils with a very shallow profile depth (indicating little influence of soil- forming processes), and they often contain large amounts of . They typically remain under natural vegetation, being especially susceptible to erosion, desiccation, or waterlogging, depending on climate and topography.

Photograph 1 Milkwood / Leptosol soil – Tigray IAIP site

The Bonheim soil form was identified over 125ha or 48% of the Tigray IAIP site (see Figure 4). This soil is characterised by a Melanic A horizon over a pedocutanic B horizon. Photograph 2 was taken during the soil survey. The pedocutanic B horizon is a layer enriched with clay as a result of illuviation and has developed a blocky structure. The Bonheim soil form also falls into the South African Melanic soil group. As mentioned, according to the World WRB Classification system (WRB, 2006), the Tigray IAIP site is dominated by Luvisols, Alisols and Retisols. Luvisols are technically characterized by a surface accumulation of humus overlying a clay illuviation horizon, and Retisols are similar to Luvisols in that they have a clay illuviation horizon, but also contain a bleached, coarser-textured soil material into the illuviation horizon forming a net-like pattern (FAO, 1998). The Bonheim soil is similar to Luvisol soils.

Photograph 2 Bonheim / Luvisol soil profile – Tigray IAIP site

SOIL FERTILITY ASSESSMENT

The productive capacity of soils depends on often complex and sometimes little understood interactions between the biological, chemical and physical properties of soil (Johnston, 2011). Soil fertility is found mostly in , however the contribution the makes should not be ignored. The fertility of the total volume of soil in which the plant roots develop should be taken into account (FSSA, 2011). According to Johnston (2011), soil analysis is an aid to managing soil nutrients efficiently to maintain soil fertility for those nutrients like Phosphorus (P), Potassium (K) and Magnesium (Mg) that are retained in soil in plant-available forms. If the amount of any of these nutrients in such forms in soil is too small then yield is jeopardised, but increasing reserves in agricultural soils to very high levels is an unnecessary expense. The laboratory results of the levels of various nutrients analysed-for in the Tigray IAIP soils are shown in Table 8-2. The guidelines for some nutrients are provided as values, and in some cases they are presented as narratives simply because some nutrients have limited or no contribution to soil fertility, thus their deficiencies or excess may not influence soil fertility as such.

Table 0-2: Laboratory Analysed Soil Nutrients at the Tigray IAIP Site

BAEK BAEK BAEK BAEK BAEK BAEK BAEK BAEK BAEK BAEK Soil ER T- ER T- ER T- ER T- ER T- ER T- ER T- ER T- ER T- ER T- Fertili PARAMETE Unit 33- 33- 37- 37- 20- 20- 17- 17- 04 04 ty RS s HORI HORI HORI HORI HORI HORI HORI HORI HORI HORI Guide ZON ZON ZON ZON ZON ZON ZON ZON ZON ZON line A B A B A B A B A B mg/k Antimony 3 3 2 2 2 2 3 2 2 3 * g mg/k Calcium 21310 18480 9201 9121 25250 22890 11240 16530 7064 7857 >150 g mg/k Copper 51 52 38 44 53 51 54 56 39 39 >0.6 g mg/k Iron 56440 70420 42690 48260 45580 43470 52410 51020 46080 46910 * g mg/k 60 – Magnesium 17250 17780 6972 7744 9784 9366 11890 12430 5540 5742 g 300 mg/k 1.0 - Manganese 996 908 505 574 614 557 549 566 416 472 g 5.0 mg/k Molybdenum <0.1 <0.1 0.2 0.2 <0.1 0.1 <0.1 <0.1 <0.1 <0.1 * g mg/k 20- Phosphorus 262 259 299 281 182 168 175 179 72 71 g 100 mg/k 150 - Potassium 842 821 1275 789 607 555 820 873 213 239 g 800 Sulphur as S % 0.01 <0.01 0.01 0.01 0.01 0.01 0.01 0.01 <0.01 <0.01 >7.5 mg/k Boron 2.09 3.19 2.57 1.29 3.46 3.01 1.68 2.04 <0.25 0.33 0.2-2 g mg/k Zinc 58 67 52 53 74 66 67 70 40 46 >1.5 g mg/k Chloride 12 NDP 14 19 5 6 15 18 15 6 5-50 g Total Organic % 0.78 1.1 1.27 1.06 1.02 0.6 0.74 1.1 0.76 1.13 * Carbon Sand % 20.0 4.9 66.3 64.7 42.1 19.1 22.4 16.6 34.2 53.4 - Silt % 78.6 92.9 32.9 34.7 53.6 65.2 75.7 81.2 62.7 44.4 - Clay % 1.5 2.2 0.8 0.7 4.3 15.7 2.0 2.2 3.1 2.2 - pH pH 8.74 9.11 8.27 NDP 9.06 8.84 8.32 8.49 7.14 7.92 6-8.2 units Total 0.1- % 0.07 NDP 0.12 0.08 0.05 0.04 0.07 0.07 0.03 0.04 Nitrogen 0.12 * Refers to the general guidelines which were not discussed in terms of ranges but a narrative description is provided in the main context

SOIL TEXTURE Soil texture drives crop production and field management as it influences drainage, water holding capacity, aeration, susceptibility to erosion, Organic Matter content, Cation Exchange Capacity (CEC) and pH buffering capacity. Soil texture is important in the context of a soil fertility analysis as soils with a higher clay content are more chemically reactive (they have a higher CEC), so tend to be more fertile (Fey, 2010). In the northern part of the site, soils with a silty loam A-horizon texture and a silty B-horizon were observed. On the western portion of the site, soils with a sandy-loam texture were observed. The soils in the centre of the study site comprise silty and in the southern portion the A-horizons are largely silty-loams and the B-horizons sandy-loams. These variations can be attributed to geology and anthropogenic influences.

PH The pH of the Tigray IAIP soils is slightly higher than the desired range of 6-8.2 at all the sites sampled aside from the southern portion where it falls within the desired range. This is expected as Melanic soils have a high base status (Fey, 2010). As pH increases, the availability of most micronutrients decreases, except for molybdenum, which becomes more available as pH increases. Micronutrient deficiencies rarely occur when the soil pH is below 6.5.

CALCIUM The Calcium (Ca) content in all the soil samples taken from the Tigray IAIP site is greater than recommended minimum levels stated in the guidelines provided by Horneck et al. (2011). In soil fertility analysis one cannot separate Ca from Magnesium (Mg), thus their management is similar. According to Schulte and Kelling (2004), the Ca:Mg ratio seldom limits plant growth if the soil pH is within the normal growing range. Ca deficiencies are usually found in very acidic soils. They can be corrected by liming with calcium carbonate (CaCO3). Calcium is rarely deficient when soil pH is adequate.

MAGNESIUM As indicated, Ca and Mg contents in soil are interrelated and the Ca:Mg ratio seldom limits plant growth if the soil pH is within the normal growing range (Schulte and Kelling, 2004). As the guidelines for acceptable levels of Mg are between 60-300 mg/kg, the Mg content in the soil samples taken from the Tigray site are very high.

POTASSIUM Horneck et al. (2011) highlights that Potassium (K) requires the most management of the three primary cations associated with soil fertility (K, Ca and Mg). Excessive K levels may be detrimental to plants. Horneck et al. also highlights that very low K content can limit the growth of some plants. Guidelines provided by Horneck et al. indicate that a K content ranging between 150-800 mg/kg in soils are advisable. The K content in the Tigray IAIP soils are largely within these guidelines and a few slightly exceed these guidelines.

COPPER A Copper (Cu) content of above 0.6 mg/kg is sufficient to support plant growth (Horneck et al, 2011). Copper deficiencies are rare and Cu was markedly above the acceptable limit in the Tigray soils analysed. ARC-SGI (2015) indicates that the availability of Cu may be very low under alkaline conditions. This is not the case in the context of the Tigray IAIP site where the soils are largely alkaline and the Cu content is high.

IRON Iron (Fe) availability in the soil is related to soil‘s pH; more acidic soils tend to have a higher Fe content. ARC-SGI (2015) highlights that Fe concentrations can be reduced under pH conditions between 6.5 and 8.0, and the higher the pH the greater the restriction. The Tigray site pH ranges between 7.14 and 9.11, and the Fe content is high.

MANGANESE Manganese (Mn) deficiencies are associated with interveinal yellowing which may also be light green in appearance. Manganese toxicities typically occur under acidic conditions (Arc-SGI, 2015). The diagnosis of either deficiency or toxicity may be attributed to pH during soil testing. Mn toxicity is common in acidic soils. The soils at the Tigray IAIP site are alkaline, yet the Mn content is very high.

MOLYBDENUM According to Horneck et al., Molybdenum (Mo) concentrations are often too low for laboratories to evaluate. The soils at the Tigray site contain Mo below 0.2 mg/kg in both horizons. A study undertaken by ARC-SGI in 2015 indicated that Mo deficiencies in soils seldom occur and thus their effects on plant growth is trivial. PHOSPHORUS Phosphorus (P) soil tests are an index of P availability described either as low, medium, high or in excess. When compared to the acceptable level of P of between 20 and 100 mg/kg, soils in the site are largely above the desired levels, with a lower P content observed towards the south of the study area where P levels fall within the guidelines. P is relatively immobile in soil. If P has been applied in a fertilizer band, concentrations of P may persist where the band was placed, making interpretation of soil test data difficult. High soil phosphorus combined with P movement from soil into surface waters can cause excessive growth of vegetation, damaging aquatic ecosystems.

SULPHUR AS S Sulphur (S) deficiencies supress protein synthesis, and high protein crops therefore have higher sulphur requirements. S deficiencies are common in sandy soils with limited organic content (FSSA, 2011); the soils at the Tigray IAIP site contain very low organic content and consequent S deficiencies. The guidelines provided by Horneck et al (2011) highlight that soils with an S content greater than 7.5 mg/kg are able to support plant growth. The Tigray IAIP site S content is below the specified range at all sampling points.

BORON Low levels of Boron (B) may limit plant growth while high concentrations may be toxic (Horneck et al, 2011). B content at the Tigray IAIP site soils falls slightly above the acceptable level of between 0.2 and 2 mg/kg, increasing toward the northern part of the site.

TOTAL NITROGEN Nitrogen (N) levels are dependent on the system of land use, climate, plant cover, soil microorganisms and the amount of readily decomposable carbonaceous material in the soil. Soil texture also influences the N supply rate of the soil. Soils with a high clay content supply more N than sandy soils (ARC-SGI, 2015). The Tigray IAIP site soil clay content is low, thus the Nitrogen content is also low. Soils with an N content between 0.1 to 0.12% are conducive to plant growth. The N content at the sites generally falls within the recommended range, but in some cases it was not possible to determine the Nitrogen content.

ZINC Horneck et al. (2011) highlight that a Zinc (Zn) content of 1.5 mg/kg is sufficient for most plant growth. The soils at the Tigray IAIP site contain Zn levels way above this. ARC-SGI (2015) denoted that a high level of P in the soil inhibits Zn uptake while high levels of N may promote Zn uptake.

CHLORIDE Chloride is a micronutrient essential for plant development, however it is required in small quantities (Chapagain et al., 2003). Horneck et al (2011), indicate that soils should contain a chloride content ranging from 5 to 50 mg/kg. Samples taken from the Tigray IAIP site indicate that the Chloride content within the site falls within levels that promote plant growth.

ANTIMONY Natural concentrations of Antimony (Sb) in the environment are low. In topsoil, Sb tends to be slightly enriched. Background concentrations of Sb in soils tend to range between 0.3 and 8.6 mg/kg (Tschan et al., 2011). The Sb concentrations measured at the Tigray sites for both the A and B horizons range between 1 and 3 mg/kg. According to Tschan et al (2009), Sb has no known essential biological functions. Similar to other trace elements, it can be toxic at elevated concentrations, and some Sb compounds are even considered potentially carcinogenic.

TOTAL ORGANIC CARBON Total Organic Carbon (TOC) is a measure of the overall and, if measured over a long period of time, can be an indication of whether the is improving. An increased in TOC in soils often indicates an increase in N and microbiological activity. Old soils are generally low in soil organic carbon. Soil type, climate and management influence the amount of organic carbon able to be stored in soil. Typically the organic carbon content in old, dryland agricultural soils is between 0.7– 4.0%, however, it can be as low as 0.3% for desert soils or as high as 14% for intensive dairy soils. The tests undertaken for the Tigray IAIP site indicate low TOC values. SOIL CAPABILITY ASSESSMENT

The soil profiles at the study site indicated mostly shallow to very shallow soils at the auger points assessed. Melanic soils are associated with a semi-arid to sub-humid climate and are fertile but require irrigation to be highly productive. Natural veld on these soils provides sweet grazing. Although their structure is strong, it is less stable than in humic soils and the soils may be more erodible. Melanic soils are generally well buffered and can be cropped intensively without needing lime to counteract acidification. Using the South African soil classification guidelines (Scotney et al., 1987), the land capability of the Bonheim soils was established as Land Capability Group ‘Arable Soils’ and Land Capability Class II, as it has ‘Slight limitations’ and ‘Low erosion hazards’ and can be used for (in order of increased intensity of use) ‘Wildlife, Forestry, Light Grazing, Moderate Grazing, Intensive Grazing, Light Cultivation, Moderate Cultivation and Intensive Cultivation‘ (Table 8.1, Scotney et al., 1987). In the context of the Tigray sites, this is accurate in that these Melanic soils do pose a low erosion hazard and pose no structural impediment to roots, but the lack of financial resources in the area and the limited soil depth highlight that these soils pose moderate limitations to growth. The Bonheim soil areas were thus allocated a soil capability class of III. The Bonheim soil form is typically fertile, well- buffered and easily managed, and thus a high yielding soil. These soils can still pose a risk to engineered structures as they do contain some shrink-swell clays (Fey, 2010). Using the South African soil classification guidelines (Scotney et al., 1987), the land capability of the Milkwood soils was established as Land Capability Group ‘Wildlife’ and Land Capability Class VIII as it has ‘Extremely severe limitations’ and is ‘not suitable for grazing or afforestation’. This is accurate in the context of the Tigray site as these soils are extremely shallow. The distribution of land capability classes can be seen in Figure 5.

8.1.1 TIGRAY RTC

DESKTOP REVIEW As mentioned, the ISRIC database shows that the Tigray RTC site is also dominated by Luvisols, Alisols and Retisols, as described in Section 8.4.2.

LAND USE ASSESSMENT At the Tigray RTC site 100% of the area is used for crop production. This can be seen in Figure 6.

SOIL CLASSIFICATION

SHORTLANDS/LUVISOL SOILS Soils that could be described as Shortlands (Oxidic) soils in the South African classification system were identified over 100% of the Tigray RTC site (see Figure 7). This soil is characterised by an Orthic A horizon over a red structured B horizon. Photograph 3 was taken during the soil survey, and shows the structured B horizon on the plastic sheet (which appeared redder than it does in the photograph), with the Orthic A horizon in the background. Oxidic soils are characterised by iron enrichment. Shortlands soils can be considered similar to Luvisols. Photograph 3 Shortlands / Luvisol soil profile – Tigray RTC site

SOIL FERTILITY ASSESSMENT

Soil analysis was also undertaken for two samples taken at the Tigray RTC site. The soil fertility results are presented in Table 8-3 and the parameters are discussed in the subsections below. Please refer to the IAIP site section for nutrient guidelines and discussions.

Table 0-3: Laboratory Analysed Soil Nutrients at the Tigray RTC Site

TIGRAY RTC-TM- TIGRAY RTC-TM-5-- Soil Fertility Parameters Units 5-- Horizon A Horizon B Guideline Antimony mg/kg 3 4 * Calcium mg/kg 11470 11600 >150 Copper mg/kg 62 62 >0.6 Iron mg/kg 62280 63470 * Magnesium mg/kg 14590 15100 60 – 300 Manganese mg/kg 912 951 1.0 - 5.0 Molybdenum mg/kg <0.1 <0.1 * Phosphorus mg/kg 143 137 20-100 Potassium mg/kg 811 762 150 -800 Sulphur as S % <0.01 <0.01 >7.5 Boron (Aqua Regia mg/kg 0.91 0.96 0.2-2 Soluble) Zinc mg/kg 61 65 >1.5 Chloride mg/kg 13 2 5-50 Total Organic Carbon % 1.13 1.13 * Sand % 8.0 23.8 - Silt % 89.8 73.7 - Clay % 2.2 2.5 - pH pH units 7.58 8.97 6-8.2 Total Nitrogen % 0.07 0.05 0.1 - 0.12 * Refers to the general guidelines which were not discussed in terms of ranges but a narrative description is provided in the main context SOIL TEXTURE The texture of the soil analysed was a Silty A-horizon and a Silty-Loam B-horizon. This limits the pH buffering capacity and CEC of the soil.

PH The pH of the Tigray RTC sample A-horizon is within the recommended range for plant growth. The pH of the B-horizon is slightly alkaline.

CALCIUM The Ca content in the soil samples taken from the Tigray RTC site is higher than the recommended minimum value for optimal plant growth.

MAGNESIUM The Mg content in the soil samples taken from the Tigray RTC sight are very high.

POTASSIUM The K content in the Tigray RTC soil samples falls within the recommended guidelines.

COPPER The Cu content of the Tigray RTC site soil samples falls above the recommended minimum limit.

IRON The Fe content of the RTC sample site is high.

MOLYBDENUM The Tigray RTC site Mo content is below 0.1 mg/kg in the two horizons, which is acceptable for plant growth.

PHOSPHOROUS The sampled Tigray RTC site P levels were slightly higher than the recommended range.

SULPHUR AS S A S deficiency was identified in the soil samples taken at the Tigray RTC site. This is likely owing to the low organic content at the site.

BORON The B content of the Tigray RTC site soils falls within the recommended range for optimal plant growth.

TOTAL NITROGEN Where it was possible to determine the N content in the Tigray RTC site samples analysed, this falls below the recommended range for optimal plant growth.

ZINC The Zn content of the sampled point at the Tigray RTC site was found to be within the recommended range for optimal plant growth.

CHLORIDE Analysis results of the samples taken from the site indicated that the Chloride content within the site falls within the recommended levels for optimal plant growth. ANTIMONY The Sb content in the Tigray RTC site soil samples was low and thus not a hindrance to plant growth.

TOTAL ORGANIC CARBON The analysis undertaken for the Tigray RTC site indicates that 1.13% TOC is present in the soils, which is low.

SOIL CAPABILITY ASSESSMENT

The soil profiles at the study site indicated mostly moderately shallow soils at the auger points assessed. Using the South African soil capability assessment guidelines (Scotney et al., 1987), the land capability of the Shortlands soil was established as Land Capability Class II; ‘Slight limitations with high arable potential and a low erosion hazard’. Shortlands soils do not present acidity issues and are highly productive when irrigated. They are typically associated with sweet grazing (Fey, 2010). In the context of the Tigray RTC site, however, the land capability would be better described as a Class III as it has moderate limitations owing to the lack of capital resources in the area. It is thus suitable for Wildlife, Forestry, Light Grazing, Moderate Grazing, Intensive Grazing, Light Cultivation and Moderate Cultivation. The distribution of land capability classes at the RTC site can be seen in Figure 8.

SIGNIFICANT IMPACTS IDENTIFIED

The following impacts were identified at both the Tigray IAIP and RTC sites as being significant in terms of soil, land use and land capability. — Erosion is not a big problem at the Tigray IAIP and RTC sites, but development of these areas, especially on the shallow soils which make up half of the IAIP site, will lead to erosion during the construction and decommissioning phases and potentially the operational phase of the development as measures will need to be put in place to prevent the eroded areas from spreading. This will have a cumulative effect on the soils identified at the sites, as eroded areas will spread until measures are put in place to stop the erosion. — Sedimentation The risk of sedimentation is directly linked to the risk of erosion, as eroded soil particles will end up in the nearby watercourses as sedimentation. As erosion is a risk at these sites and they are close to watercourses (and a watercourse runs through the IAIP site), so is sedimentation. As erosion will have a cumulative effect, so will sedimentation. — Loss of topsoil Although the topsoil will be lost from these sites during the construction phase, it can potentially be transferred to an alternative area for continued cultivation. The measures outlined below would need to be followed in order to reuse the topsoil though. Limited topsoil will be available from the IAIP site as a large proportion thereof comprises Milkwood/Leptosol soils (very shallow). — Soil compaction Significant soil compaction will occur in some areas of the sites during the construction phase – these areas should be limited. Compaction of a large proportion of the site will occur during the operational phase. Although soils could be ripped after decommissioning of the site, the soils will never regain their original structure so this cannot be mitigated against. — Change in surface profile In order to create platforms for the agri-industrial zone buildings, the surface profile of the sites will be changed during the construction phase. This will affect water flow, sedimentation and erosion patterns. — Change in land use The proposed development activities will result in a permanent change of land use during the construction and operational phases, and therefore result in a high impact. Land use will change from farming to an agri-industrial zone. As mentioned, although soils could be ripped after decommissioning, original cannot be returned to the soils, so this cannot be mitigated against. — Change in land capability Similarly to land use, land capability will also be permanently altered during the construction phase, owing to the proposed development. — Dust creation Dust creation has been identified as a potential risk until bare surfaces and soil stockpiles are watered and vegetated. — Soil is likely to be contaminated during the construction and decommissioning phases as large vehicles will be on site, thus on-site pollutants’ contact with these well-drained soils will need to be limited. There is also a risk of soil contamination during the operational phase, although these will largely be different kinds of pollutants. In all phases soil contamination can and should be prevented, especially as these contaminants will likely quickly enter the nearby water resources.

RECOMMENDED MITIGATION MEASURES

SOIL EROSION CONTROL The following soil protection strategies are taken from the International Finance Corporation (World Bank) Environmental, Health and Safety Guidelines for Mining, 2007 (IFC, 2007). These guidelines are applicable to projects outside of the mining sphere and can be used to guide construction, operation and decommissioning activities at the proposed Tigray sites: — Placement of soil stockpiles so as to prevent exposure to wind and water erosion. — Access and haul roads should have gradients or surface treatment to limit erosion, and road drainage systems should be provided. — Terracing, slope reduction, runoff velocity limitation and the installation of appropriate drainage; should be incorporated into the site management plan to limit soil erosion. Further to this, the erosion guidelines in the Western Tigray Industrial Parks Development Corporation Document (Federal Democratic Republic of Ethiopia, 2017) states the following: — Reduce negative impacts to the site and surroundings by controlling erosion and sedimentation. — Soil erosion control measures shall conform to the best management practices highlighted in the appropriate code. — Regular inspections will be undertaken to assess erosion and sediment migration from topsoil stockpiles. Where unacceptable rates of erosion are identified, remedial works will be undertaken, or the stockpile will be relocated. — The size and area of stockpiles of soil will be minimised. Stockpiles that may be susceptible to erosion must be terraced, covered or have suitable erosion control measures such as silt fences. — Soil stockpiles should be revegetated to protect the soils against erosion.

SEDIMENTATION CONTROL The IFC (2007) guidelines specify the following sedimentation control management measures: — Reduce and prevent off-site sediment transport by using measures such as settlement ponds and silt fences. — The implementation of soil erosion mitigation measures will also mitigate against enhanced sedimentation. TOPSOIL MANAGEMENT Based on the Tigray IAIP and RTC sites’ very low soil TOC measurements, stockpiled topsoil TOC should be increased prior to reuse of the topsoil by adding additional organic matter to the soil. The IFC (2007) guidelines specify the following topsoil management measures: — Topsoil stripped should be stockpiled for rehabilitation. — Irrespective of where topsoil is stockpiled, it should be kept moist and vegetated as soon as possible. — Topsoil stockpiles should be kept low (between 3 and 5 meters tall). It is recommended that the top 50cm of soil be stripped, where possible according to the guidelines below; — Demarcate the area to be stripped clearly, so that the contractor does not strip beyond the demarcated boundary. — The top 50cm of the entire area should be stripped, where the soils are deep enough, and relocated by truck along set removal paths. — The area to be stripped requires storm water management; the in-flow of water should be prevented with suitable structures. — Prepare the haul routes prior to stripping. — Stripping should not begin in wet conditions. — Within each stripping unit, segments should be stripped progressively, ensuring that the dump truck used to move the soils does not drive over the area to be stripped, but rather behind it on the basal layer, in order to avoid compaction and degradation of the topsoil properties (Humphries Rowell Associates, 2000). — When stockpiled soils are to be used elsewhere, the soil fertility should be assessed to determine the level of fertilisation required to sustain normal plant growth. The fertility remediation requirements need to be verified at the time of rehabilitation. The topsoil should be uniformly spread onto the rehabilitated areas and care should be taken to minimise compaction that would result in soil loss and poor root penetration (Viljoen and Associates, 2012). — The Environmental Protection Agency (EPA) generally requires that maximum stockpile heights for material management or resource recovery activities be in the range of 3 to 5 metres. These stockpile height limits are largely based on stockpile manageability, dust impacts, stability, potential impacts to underlying infrastructure and fire risk. The height of stockpiles should generally be lower than surrounding structures. Greater stockpile heights will need careful and adequate assessment of all the additional risks the increased height poses and it must be demonstrated that these risks can be managed, as excess height can also lead to other safety risks such as instability. The Western Tigray Industrial Parks Development Corporation Document (Federal Democratic Republic of Ethiopia, 2017) states the following in respect of topsoil (in addition to the erosion specifications highlighted above: — Fertile topsoil is to be stockpiled before construction, for future reuse or donation. The term ‘fertile’ is not defined here, so in the case of the Tigray sites’ topsoil, it would depend on the need for this soil elsewhere. The topsoil at the site had been successfully used to grow crops in previous years. — Topsoil within the top 25cm should be carefully extracted and secured. Please note that the IFC (2007) guidelines refer to the top 50cm being topsoil but the Industrial Parks Development Corporation Document should be adhered-to in this case as it is site-specific. Based on the soils identified at the sites, the deeper are closer to 25cm in depth than 50cm and some are extremely shallow. — Topsoil mounds of 1-2m high are recommended. Please note that the IFC (2007) guidelines specify stockpiles of 3-5m high, but, again, as the Industrial Parks Development Corporation Document is site specific, it should be adhered-to. — Stockpiled topsoil must be revegetated to protect against erosion, discourage weeds and maintain active soil microbes.

COMPACTION MANAGEMENT The IFC (2007) guidelines specify the following compaction management measures: — Pre-defined, essential road routes should be clearly demarcated and adhered-to on site to restrict soil compaction to certain areas. — Vehicles should not drive on soil when it is wet to avoid further soil compaction. Having said this, once soil is well-compacted, little further damage or rehabilitation can be done. The Industrial Parks Development Corporation Document states that compacted surfaces will be deep ripped to relieve compaction where possible. It should be noted, however, that, once compacted, soils cannot regain their original soil structure. The Industrial Parks Development Corporation Document further specifies that: — Soils must not be stripped when they are wet as this can lead to compaction and loss of structure.

DUST SUPPRESSION MANAGEMENT The IFC (2007) guidelines specify the following dust suppression management measures: — When stockpiling soil one runs the risk of producing dust. The advised longer-term solution to this problem is to vegetate the soil as plant roots bind soil and protect the soil against the wind. Good vegetation coverage is necessary for this to be successful. — As a shorter-term solution – for the period between stockpiling and plant growth – keeping the stockpiles damp will mitigate against the risk of dust creation. — As mentioned, the Environmental Protection Agency (EPA) generally requires that maximum stockpile heights for material management or resource recovery activities be in the range of 3 to 5 metres. These stockpile height limits are largely based on stockpile manageability, dust impacts. The Industrial Parks Development Corporation Document specifies that: Stockpiled soils should be located in areas where trees can act as buffers to prevent dust pollution.

CONTAMINATION MANAGEMENT During the construction and decommissioning phases: — On-site vehicles should be well-maintained, — Drip trays should be placed under vehicles and — On-site pollutants should be contained in a bunded area and on an impermeable surface. During the site operational phase: — One should maintain control of substances entering the site, — Provide adequate disposal facilities, and — Enforce a non-polluting environment. The Industrial Parks Development Corporation Document specifies that: — One should identify potentially toxic overburden and screen with a suitable material to prevent mobilisation of toxins.

CONCLUSIONS

At the Tigray IAIP site 100% of the area is currently used for crop production. Half of the soils identified at the Tigray IAIP site were very shallow, erosive soils and the other half were moderately shallow, structured soils. These soils are a combination of arable with moderate limitations owing to the lack of capital resources in the area (so could be suitable for Wildlife, Forestry, Light Grazing, Moderate Grazing, Intensive Grazing, Light Cultivation and Moderate Cultivation) and, in the case of the very shallow soils, suited only to wildlife as they have extremely severe limitations and are not suitable for grazing. This is accurate in the context of the Tigray site as these soils are extremely shallow. In short, the Tigray IAIP site had been successfully cultivated, thus the change in land use of this site will result in a loss of arable land for the local farmers. At the Tigray RTC site 100% of the site is again used for crop production. The main soil identified is relatively deep, fertile, well-drained yet structured. The soil capability is arable with moderate limitations owing to a lack of financial resources, so could be suitable for Wildlife, Forestry, Light Grazing, Moderate Grazing, Intensive Grazing, Light Cultivation and Moderate Cultivation. The more easily mitigatable risks identified to the soils at both sites include loss of topsoil, dust creation, and contamination. Erosion, sedimentation and soil compaction can be avoided to some extent but to a large degree cannot be mitigated against. The inevitable changes in the surface profile, land use and land capability as a result of the development cannot be mitigated against. Mitigation measures to be implemented will be most important during the construction phase. The residual impacts on the soil as a result of the development will include the following: Soil Erosion: Excavating the soils in order to develop the Tigray IAIP and RTC sites will lead to soil erosion, especially on the very shallow soils that make up half of the IAIP site. This can be mitigated against through the measures described in the previous sub-section, but excavation of these soils is generally likely to lead to some erosion. Sedimentation: A residual soil erosion impact will lead to a residual sedimentation impact as eroded soil particles will enter the nearby watercourses as sediment. Compaction: All soils that have been compacted will have lost their original structure permanently. Change in surface profile: As the site will be levelled for the development, the land surface profile will be permanently altered. Change in land use: As the soils will be excavated, compacted and possibly sterilized, the land use will very likely change from arable permanently. Change in land capability: As the soils will be excavated, compacted and possibly sterilized, the land capability will very likely change from arable permanently. Soil Contamination: Contaminated soil is expensive to rehabilitate and contamination entering the soils of the Tigray sites may enter the surrounding water resources. Mitigation measures can be very expensive and require appropriately-skilled personnel to be a part of the impact mitigation team.