Review on successful soil conservation methods in Ethiopia

Abstract

Ethiopia’s low agricultural productivity and loss of soil nutrients are primarily due to land degradation. By interfering with natural processes, it deteriorates soil properties and endangers agricultural production. Different soil and water conservation (SWC) practices have been implemented in many regions of Ethiopia to combat it. Reviewing successful soil conservation methods in Ethiopia and their impacts on soil properties, agricultural productivity, and technical soil conservation quality are the main goals of this paper. Data were gathered from a range of sources, including publications on soil conservation, conferences, thesis works, and periodicals. SWC practices had either a positive or negative impact on the soil’s physicochemical characteristics and crop productivity. Under both biological and integrated SWC practices, the mean values of pH, TN, AVP, OM, and CEC were higher on treated farmland than on untreated farmland. Under all SWC practices, the average bulk density was higher on acreage that had not been treated than it had been. By effectively using SWC technology and integrating physical and biological measures, the technique for repairing soil physicochemical properties, reducing soil erosion, and enhancing agricultural productivity would be improved. In order to improve technical quality, soil quality, crop yields, and society’s means of subsistence, it is therefore possible to advise that the layout of conservation measures, intensive capacity building about the layout of structures, and standard procedure be followed.

Keywords:

• soil properties
• soil erosion
• land degradation
• soil and water conservation

PUBLIC INTEREST STATEMENT

The second-most populated nation in Sub-Saharan Africa is Ethiopia. Overpopulation has resulted in severe deterioration and depletion of the land’s resources as well as a quick collapse of the ecological and social systems. Soil erosion is one of the reasons for soil degradation. Population pressure causes overgrazing, cultivation of steep hillsides, and cultivation of marginal regions, which all speed up soil erosion. The efficiency with which plant nutrients are used, seeding, root depth, soil water holding capacity, permeability, runoff, and infiltration rate are all negatively impacted by erosion, which also degrades soil productivity. Soil and water conservation techniques are crucial for stopping land deterioration in the nation. Numerous soil and water conservation methods have been implemented nationwide to reduce soil erosion and land damage. The review found that effective soil water conservation practices, particularly those that incorporate physical and biological mechanisms, improve soil quality, land productivity, and crop yields.

1. Introduction

One of the sub-Saharan African nations that are most severely impacted by land degradation is Ethiopia (Federal Democratic Republic of Ethiopia FDRE, 2015). Low agricultural production and soil nutrient loss in the country are mainly caused by land degradation (Demissie et al., 2022). The minimum anticipated yearly costs of land degradation in Ethiopia vary from 2 to 3% of agricultural GDP (FDRE, 2015), without taking into consideration downstream and offsite impacts like flooding and infrastructure damage brought on by erosion. According to Agricultural Transformation Agency (ATA) (2013), Ethiopia’s soils are largely severely deteriorated. The highlands of Ethiopia (>1500 masl) have had the highest levels of land degradation due to soil erosion (Dimtsu, 2018). The region’s ability to produce food sustainably is being jeopardized by these high erosion rates (Zeleke & Welemariam, 2020). Rapid population expansion of people and animals (overgrazing) results in higher soil erosion rates, decreased plant production, and an all-around overuse of natural resources (Bekele et al., 2021).

One of Ethiopia’s main environmental issues is soil erosion, which lowers the production of arable fields. Among the causes of soil erosion are erosive rains and rocky topography. According to Dimtsu (2018), the average yearly rate of soil loss in the country is estimated to be 12 t ha⁻¹ year⁻¹; however, on steep slopes and in areas with little vegetation cover, this rate can reach 300 t ha⁻¹ year⁻¹. Degradation in agricultural areas is accelerating due to ineffective planning and implementation methods for conservation and poor land and water management practices. Since steep slopes have been used for agriculture in the Tigray Region of Northern Ethiopia for many years, they are vulnerable to significant soil erosion (Mekuria et al., 2018). In Ethiopia, soil erosion is predicted to result in a 1–2% annual output decline (Yaekob et al., 2022). The soil’s chemically active components, such as organic matter and clay fractions, which are its most productive components, are removed by erosion. Additionally, it worsens soil structure and capacity to retain moisture by decreasing soil depth, raising bulk density, causing soil crusting, and lowering water infiltration. Crop yields are steadily dropping because of erosion and depleted fertility, and the typical Ethiopian farm family of roughly six people currently harvests less than a tone of grain every year, which is insufficient for the subsistence diet (Alemu et al., 2013).

Therefore, such circumstances necessitate vigorous conservation efforts. With assistance from foreign organizations, the Ethiopian government has dedicated significant emphasis to conservation and environmental rehabilitation projects since the early 1980s. Bunds, tree planting, and the sealing of degraded areas are typically used in a package of conservation measures. Food-for-work (FFW) programs provided funding between 1976 and 1988 for the construction of 800,000 km of soil and stone bunds on arable land, 600,000 km of hillside terraces, and 80,000 hectares for regrowth and afforestation on steep slopes (Alemu et al., 2013). The Soil Conservation Research Program (SCRP) in Ethiopia was first developed in 1981 when the Ethiopian Government requested assistance from the Swiss Agency for Development and Cooperation to help establish a research network through the University of Berne. The SCRP’s primary goal was to assist Ethiopian efforts to conserve soil by tracking soil erosion and relevant influencing factors, developing effective soil and water conservation measures, and increasing local and global research capacity (Alemu et al., 2013). It entailed choosing benchmark locations with a range of socio-cultural contexts across numerous distinct agro climatic zones of the nation. Maybar in Wello (1981), Hunde Lafto in Hararghe (1982), Andit Tid in Central Shewa (1982), Anjeni in Gojjam (1984), Afdeyu in Eritrea (1984), Gununo in Wolayta (1982), and Dizi in Illubabor (1982) were chosen as the SCRP benchmark sites. The programs throughout this time mainly aimed to lessen soil erosion. Between the 1970s and 1990s, the majority of soil and water conservation (SWC) initiatives were focused on minimizing soil erosion rather than increasing agricultural output. Neither successful nor sustainable, these efforts lacked synergy between farm and non-farm measures (Gebregziabher et al., 2016). In order to promote sustainable water and land resource management based on partnerships with the community, the SWC activities of the project have been developed into a participatory integrated watershed management strategy since the end of the 1990s (Agidew & Singh, 2018).

The goal of the participatory, integrated watershed management strategy is to increase the productivity of water and land resources while maintaining institutional and ecological viability (Pretty et al., 2020). Watershed management is becoming a key component of the agenda for rural development and poverty reduction. According to the participatory watershed management guidelines (Mena et al., 2018), the goal of watershed management is to enhance rural communities’ and households’ standard of living through (i) using rainfall for better groundwater replenishment; (ii) implementing appropriate soil, water, fertilizer, and crop management practices to advance sustainable farming systems and agricultural output; (iii) restoring and reclaiming marginal lands using suitable conservation measures, such as planting shrubs, trees, and grasses based on potential already present; (iv) diverse agricultural practices and money-generating activities to increase smallholders’ income; (v) SWC for beneficial applications. From this goal, appropriate conservation actions are assessed, such as planting trees, shrubs, and grasses based on the potential already present, as well as rehabilitation and reclaiming marginal lands.

According to research on the effects of SWC practices, they may enhance soil physicochemical qualities, decrease soil loss due to sediment trapping, enhance crop growth and yield, and increase farmers’ income (Mishra et al., 2019). However, some mechanical structures were unable to consistently have a favorable impact on some particular outputs, most notably crop yields. The standard soil laboratory analysis from croplands with level soil bund and stone bund and non-terraced did not show remarkable difference for some parameters and even less for some sites (Wolka et al., 2011). This was caused by inadequate adoption, implementation strategies, inappropriate technology use, improper SWC management, inappropriate physical structure construction, and a disconnect between physical and biological conservation measures, which exemplify the land for further soil erosion, reduce arable land, and act as a physical barrier. Furthermore, Ethiopia neglects to evaluate the SWC in a timely manner. This will likely discourage SWC practices. A few researchers have investigated the suitability of soil conservation strategies based on agroecology (arid, semi-arid, and humid), but their analysis does not demonstrate consistency. Many researchers have assessed the influence of SWC practices on soil physicochemical parameters and crop output. The success of SWC practices is influenced by a variety of factors. As an example, the age of structures (Tanto & Laekemariam, 2019), integration of physical and biological activities (Aleminew & Alemayehu, 2020), type of physical practices (Ejegue & Gessesse, 2021), and soil fertility status of the land at a time when SWC measures were applied would all affect the potential of SWC practices to reestablish soil properties and result in greater crop yields. In order to execute soil conservation practices at the level of fields, farms, and watersheds sustainably, it is important to take into account information relevant to soil, crops, and management. The objective of this review is to assess Ethiopia’s effective soil conservation methods and their impact on soil properties, agricultural productivity, and technical soil conservation quality.

2. Methodology of review

The review was conducted in different regions of Ethiopia: Amhara region (minchet catchment, Zikre watershed, Debre Yacobe micro-watershed, and Anjeni watershed), Oromiya region (Goromti watershed), Tigray region (Maego watershed and middle Silluh valley), south nation nationality and people regional state (KambataTambaro, Wollayita, and Dawro zone), and Sidama region. Data were gathered from secondary sources via a computer library using a variety of databases, including Web of Science, Research Gate, Google Scholar, and Science Direct, based on defined criteria, to fulfill the intended goal of this review work. For information on physical, biological, and integrated soil water conservation practices, including soil physicochemical parameters, crop yield, and the year (age) of the SWC practices, the main and target literature were consulted. Detailed requirements and the inclusion and exclusion groups for each were listed in the Appendix table.

3. Content of review

3.1. Adoption of soil conservation in Ethiopia

Ethiopia has a total surface area of 111.8 million hectares, of which 60 million hectares are regarded as agriculturally productive. More than 2 million ha of Ethiopia’s highlands have been damaged beyond recovery; 27 million hectares were extensively eroded, and 14 million hectares were severely degraded (Balabathina et al., 2020). Furthermore, according to Assefa and Hans‐Rudolf (2016), Ethiopia loses 1.5 billion tons of soil annually due to erosion, of which 50% happens on cultivated land. Due to farmers’ inability to tolerate additional degradation in soil productivity, such losses may result in irreversible changes in soil productivity that has a direct impact on Ethiopia’s food security situation. As a result, agricultural production in Ethiopia’s highlands is poor (Yifru et al., 2022).

After the famine in 1973–74 (Yewollo Rehabi), the Ethiopian government became aware of the effects of soil degradation for the first time. Since then, a sizable programme of soil conservation and rehabilitation has been implemented in the most severely degraded areas (Assaye, 2020), involving the mobilization of peasant associations and the participation of more than 30 million peasant workdays annually. According to reports, between 1975 and 1989, 980000 hectares of cropland were converted into terraces 208,000 hectares of hillside terraces were erected, and 310,000 hectares of heavily deforested land were restored to vegetation (Bobe, 2004). However, these results fall far short of expectations, and despite great efforts, the nation continues to lose a sizable amount of valuable topsoil each year.

To stop soil loss due to water erosion, two soil conservation strategies (the barrier method and the cover strategy) have been developed and are in use globally (Wolka, 2014). Runoff and the sediment it carries are blocked by using semi-permeable structures like grass strips and hedgerows, as well as soil conservation techniques including terraces, channels (bunds), and stonewall. The cover strategy typically uses plant materials as well as other objects, such as stones, plastics, and industrial trash, to block raindrops from striking the soil surface and lower runoff volume and velocity.

3.2. Implementation of soil conservation through community based participatory watershed developments in Ethiopia

In Ethiopia, there were very few watershed initiatives. The Food and agricultural Organization (FAO)-led institutional strengthening initiative primarily aimed to increase the skills of the technicians, experts, and development agents working for the Ministry of Natural Resources in the country’s highland areas. In order to produce land use and capability plans for soil and water conservation, the projects employed the sub-watershed as the planning unit and sought the opinions of local technical experts and members of the farming community. The creation of the participatory planning method for watershed development began with this. By the end of 1990, the focus of rural development and poverty reduction was thought to be watershed development. With the assistance of government partners, a number of organizations have adopted watershed development in the past ten years in their intended intervention regions. For instance, the land rehabilitation project with Food-for-Work support sought to address the issues of food insecurity through the creation of community forestry, rural infrastructure projects, and soil conservation structures. The initiative concentrated on a few watersheds in the nation that have a food shortfall and have the highest rates of chronic food insecurity.

Organizations have acknowledged that protecting watersheds requires the willing involvement of the local population (Woldeab et al., 2022). Therefore, public involvement is crucial for effective and long-term watershed management. In addition to individual plots, managing a watershed involves common property assets including forests, springs, gullies, roads, and walkways, as well as vegetation along streams and rivers. Each watershed has varied objectives and needs for its many users. Farmers can be asked about their limitations, priorities, and aptitude for utilizing new technologies so that the best policies and technologies can be developed for each watershed. Therefore, participatory watershed management incorporates all participants in a project’s implementation, monitoring, and evaluation phases (Walle, 2022). Participants discuss their interests, prioritize their needs, assess prospective alternatives, and evaluate viable alternatives.

For watershed development programmes to be successful, user involvement is essential. A participatory approach indicates that the community has a significant role to play and entails collaborations with other interested organizations at all levels, including policymakers. The main issue, however, is to find strategies that can create a channel of communication that is efficient, effective, and accountable between the community, local governments, the state, and central organizations (Kimengsi & Azibo, 2017). Participation, according to Hamilton et al. (2019), entails that stakeholders collaborate to establish standards for sustainable management, identify constraints and objectives, consider potential solutions, suggest technologies and policies, and monitor and assess impacts. Clarification is needed as to how, who, and what exactly is participating because the nature of participation is frequently ambiguous. Participatory watershed management, or as Wood Hills put it, “making the invisible visible” (Pretty & Ward, 2001), is not a neutral idea; rather, it is a complicated system that encompasses political problems relating to who has access to resources and who has the power to make decisions.

3.3. Agro ecologically suggested soil conservation in Ethiopia recently

The following measures (Table 1 and 2) are arranged in suggestive order depending on the primary agroclimatic conditions and land usage. As many measures serve several purposes (for example, both for forestry and feed, for water harvesting and conservation, for improving soil fertility and moisture conservation, and so on), this categorization is informative. However, they are mostly classified depending on their principal or most pertinent role for practical reasons (Desta et al., 2005).

Table 1. Physical soil and water conservation measures

Soil conservation techniques	Main land use	Suitability based on agroecology
		Arid (kolla) up to 500mm RF	Semi-arid (dry Woyina Dega) 500-900mm RF	Medium/high RF areas (Woyina Dega/Dega) >900mm
Soil bunds	CL, HL, GL	Suitable with large trenches	Suitable with trenches	In Dega may need to be graded
Stone bunds	CL, HL, GL, F/SL, Ms	Suitable with large trenches	Suitable ± trenches	Suitable without soil fill on upper side of bund
Stone faced soil bund	Cu, HL, GL, F/SL, Ms	Suitable with trenches	Suitable ± trenches	In Dega may need to be graded
Fanya juu bunds	Cu, HL, GL	Hot suitable	Suitable ± alternate with trench soil bunds	Suitable in deep soils (>100 cm) - may be graded in Dega zone
Bench terraces	CL, GL	Suitable with runon/runoff system	Suitable	Suitable ± may need excess water disposal structures

CL; cultivated land; HL: Homesteads; GL: Grazing lands; F/SL: Forest/Scrub land (usually steep slopes); Ms (miscellaneous-degraded areas under multiple uses).

Table 2. Biological soil conservation practices

Measures	Main land use	Suitability based on agro ecology
		Arid (Kolla) up to 500mmRF	Semi-arid (dry Woyina Dega) 500-900mmRF	Medium/high RF areas (Woyina Dega/Dega) >900 mm
Contour cultivation	CL, HL	Suitable with SWC measures and tie ridges	Suitable with SWC measures	Partially Suitable (specific soil conditions only)
Grass strips along the contours	CL, HL	Generally, not suitable	Suitable only with drought resistant species and/or combined with conservation structures	Suitable
Stabilization of physical structures	CL, HL, F/SL, GL	Suitable with very drought resistant species	Suitable with drought resistant species	Suitable
Vegetative fencing and stabilization (Closures, gullies and farm boundaries)	Ms, F/SL, CL, GL	Suitable with drought resistant species and support structures	Suitable	Suitable
Strip cropping	CL, HL	Suitable (supplemented by irrigation)	Suitable in benched areas	Suitable
Ley cropping	CL, HL	Not suitable	Suitable in fallows within areas treated with SWC measures	Suitable in fallows within area: treated with SWC and drainage measures
Cover/green manure crops	CL, HL	Suitable with drought tolerant legume crops	Suitable	Suitable
Relay cropping	CL, HL	Not suitable unless under irrigation	Suitable	Suitable
Mulching and crop residues management	CL, HL	Suitable (mostly around homesteads)	Suitable (mostly around homesteads) and along conservation structures + compost	Suitable
Crop rotation	CL, HL	Suitable (crops with different rooting zones) combined with SWC and/or irrigation	Suitable	Suitable

CL; cultivated land; HL:Homesteads; GL: Grazing lands; F/SL: Forest/Scrub land (usually steep slopes); Ms (miscellaneous-degraded areas under multiple uses).

3.4. Specific soil conservation practices in a selected watershed, Ethiopia

3.4.1. Debre Yacob micro-watershed, northwest Ethiopia

Debre Yacob Micro-Watershed is located in Amhara region, north western Ethiopia. The purpose of the study was to compare and contrast bunds stabilized with pigeon pea and Sesbania sesban. Finger millet and maize were the crops evaluated. The outcomes showed that crop productivity had increased as a result of conserving soil and water. Teff yields on non-conserved fields averaged 2946 kg ha⁻¹, while yields on bunds stabilized with Sesbania sesban and pigeon pea fields were 4344 and 4484 kg ha⁻¹, respectively (Table A1). The average yield of finger millet on untreated fields was 1200 kg ha⁻¹, 1716 kg ha⁻¹ for bunds stabilized with Sesbania sesban, and 1856 kg ha⁻¹ for bunds stabilized with pigeon pea. According to the study’s findings, preserved farm plots produced a mean crop production that was considerably higher than non-conserved treatments (Alemayehu & Fisseha, 2018).

The study’s findings demonstrated that conserved and non-conserved plots differed significantly. The highest soil pH, OM, TN, AVP, and CEC, as well as the lowest BD, were found in the preserved plots. This indicates that structural conservation practices (bund) in conjunction with plant species (Sesbania sesban and pigeon pea) are successful in enhancing the soil’s physicochemical qualities in the research area. According to Sinore et al. (2018), soil treated with sesbania and elephant grasses had a significantly greater CEC and exchangeable bases than untreated soil. Sesbania plants or grasses used to support terracing strengthen the bund, produce high biomass, boost OM, and improve erosion control, all of which lead to an increase in soil CEC. Similar to this, Adjei-Nsiah (2012) found that pigeon pea leaf litter keeps soil nutrients available, lowers soil erosion, improves infiltration, minimizes soil heating, and promotes earthworm activity by covering the soil. The farmers believed that crops planted on the ground following pigeon pea appeared greener, grew more quickly, and produced more.

3.4.2. Middle Silluh valley, Tigray region

The investigation covered an area of 490 km² and was conducted in Ethiopia’s northern highlands, in the Middle Silluh Valley. According to Hishe et al. (2017), the study area is agro-ecologically distinguished by the Woyna dega (mid land) and Dega (highland) ecoregions, which have mean annual rainfall totals of 536 mm and minimum and maximum mean annual temperatures of 10.7 °C and 26.6 °C, respectively.

The study has shown the effects of various soil and water conservation techniques on the physical and chemical characteristics of the soil in the Middle Silluh Valley, northern Ethiopia. Terracing and enclosure areas are examples of conserved landscape types that have higher clay contents than non-conserved landscape categories like non-terraced farm land and pasture land. The conserved landscapes (terraced hillside, terraced farmland, and exclosure area) were reported to have a significantly lower mean value of BD than the non-conserved landscapes (non-terraced field land, non-terraced grazing land, and non-terraced hillside). According to Jiru and Wegari (2022), the existence of much more SOM as a result of conservation efforts and plant residue degradation may be the cause of the protected landscape’s lower bulk density.

The SOM and TN of the soil have improved as a result of the SWC procedures that were implemented on the study area’s slope. This served as a solid benchmark for future application of SWC solutions to the region’s other damaged hillside environments. There is no statistically significant difference between the mean values of exchangeable Ca⁺², Mg⁺², K⁺, Na⁺, and the sum of exchangeable bases in the study area’s conserved and non-conserved landscapes. Despite the use of SWC methods, the sandstone parent material of the research region and the soil’s acidity worsen the lack of exchangeable cations.

Overall, it was discovered that the Middle Silluh River SWC intervention had clearly positive effects on certain selected soil physical and chemical parameters. The various conservation techniques used in the area, such as bench terraces, soil bunds, stone bunds, check dams, trenches, preserving area enclosure, and re-afforestation, were crucial in preventing soil erosion as well as protecting soil fertility (Hishe et al., 2017). Similar to this, Mishra et al. (2020) observed that agricultural terracing became recognized as one of the most promising mechanical techniques for soil conservation. It has dramatically decreased soil loss, raised soil fertility, boosted yields of crops, and enhanced socio-economic development.

3.4.3. Bashemicro watershed, southern Ethiopia

The study was carried out in the Bashe micro-watershed, which is a part of Southern Ethiopia’s Wolaita Zone’s Damot Gale district. The study region is agro-ecologically characterized by Woyna Dega (mid land) and Dega (highland), with an altitude range of 1805–2601 m. The mean annual rainfall is 800–1500 mm, and the lowest and highest mean temperatures are 18 °C and 25 °C, respectively (DGWFED Damot Gale Woreda Finance and Economic Development, 2016).

According to a study done in the Bashe micro-watershed, there are noticeable differences between croplands with physical soil conservation (2 and 5 years old), physical conservation integrated with biological practices (2 and 5 years old), and non-conserved land in terms of growth, yield component, wheat yield, and soil physicochemical properties (Table A2). According to a study by Tanto and Laekemariam (2019), integrated SWC practices that have been in place for five years have an advantage over non-conserved land in terms of grain yield of 72.9%. According to Wolka et al. (2018), this may be related to decreased runoff, maintained moisture, and increased nutrient availability throughout the growth phase, which are improving soil characteristics and grain output. It is a fact that changes in soil characteristics and crop output increase as an establishment ages and physical work is combined with biological practices. Farmers would gain from the stabilization of physical SWC structures by providing fuel and fodder by planting multipurpose grasses and plants. This is in line with the findings of Tanto-Doko (2022), who found that farming land with integrated soil and water conservation practices along with plant species (Sesbania sesban and pigeon pea) and physical structure conservation practices (Bench terrace and Deep trench) had higher soil pH, SOC, TN, AVP, CEC, and productivity than farmland with physical structure alone and farmland without conserved physical structure.

When all other factors remain constant, an increase in crop production of 46.66 coefficients would result from an increase in the age of established SWC practices by one year (Jiru & Wegari, 2022). This is due to the fact that SWC practice has contributed to decreasing soil erosion, soil loss, and runoff while also improving some soil physicochemical qualities. This is in line with the findings of Hailu et al. (2020), who observed that a particular soil’s physicochemical properties (pH, SOC, TN, CEC, AVP, Clay, Silt, BD, and Sand) are enhanced as the number of years that SWC practices are used increases. As a result, it is evident that SWC practices have a positive influence on the soil fertility and crop yield of farmed fields.

3.4.4. Minchet catchment

The SCRP includes the Minchet catchment, which was established in 1984 and is located in the northern Ethiopian Highlands. With graded fanya juu, canals, check-dams, reforestation, and the preservation of degraded grazing plots for rehabilitation, the watershed was completely rehabilitated in 1986 (Subhatu et al., 2017). The bunds and trench below in a graded fanya juu have a lateral gradient of roughly 1% to 5% and are thus connected to the built-in waterways (Hurni et al., 2016), allowing run-off to drain to the river (Hurni et al., 2005). The graded fanya juu’s bund components were well-maintained and over time transformed into terraces that slope outward, while the trench quickly filled in or was demolished after being built.

According to the study carried out in the catchment, the sub-humid Ethiopian Highlands’ Minchet catchment clearly demonstrated the deposition of degraded soil by water on terraced croplands. Such deposition primarily occurs in the terraced field’s deposition zone, above the riser slope of the terrace. It was found that between 54 and 74% of the soil lost during the 2014 and 2015 crop growing seasons was deposited on terraced farmland, which is a very encouraging result of SWC technologies to reduce soil erosion and improve soil quality in the area. However, net soil loss exceeding the study area’s tolerable level was noted, particularly in terraced fields with greater distances between terraces. Fewer terraces and smaller deposition areas per hectare are the results of the increased spacing between terraces. As a result, the terraces with broad spacing had less tone deposition per hectare than those with narrow spacing. In comparison to observation plots with wider spacing and a gentle slope gradient, those with narrower spacing and a steeper slope gradient showed more on-site sediment deposition. Thus, there are two strategies to sustainably conserve more soil in farming. First, by increasing the number of terraces, particularly through steeper slope gradients and wider spacing, and second, by making the terrace productive by planting, such as fodder grass, to make up for the space that crops would normally grow in. Studying on-site sediment deposition without interfering with the normal processes of soil erosion and deposition proved rather difficult methodologically. This study did so with little sway. As a consequence, it is advised to keep developing SWC technologies in order to reduce net soil loss even further and to increase the capacity for on-site sediment deposition (Subhatu et al., 2017).

3.4.5. Goromti watershed, western Ethiopia

Goromti Watershed is found in Oromia Regional State, western Ethiopia. In the Goromti watershed, the usage of Fanya juu as a structure for soil and water conservation has been found to be helpful in preventing erosion and the resulting nutrient depletion on the farmed area. Additionally, the findings of the soil research revealed that the majority of the soil’s physical and chemical qualities varied significantly depending on management techniques and slope gradients. Compared to non-conserved agricultural plots, the bulk density of the soil was lower under the conserved farm plots (Table A4). Slope gradients also affected bulk density and the textural fractions of sand and clay. According to Hailu et al. (2012), differences in soil chemical properties were primarily caused by soil management practices rather than the inherent characteristics of the soils because there were no statistically significant differences between conserved and non-conserved farm plots in terms of physical properties (primarily clay contents). It was discovered that treatments and slope gradients affected soil organic matter, total nitrogen, and pH. The various soil physical and chemical parameters generally indicated that the SWC structures had a good impact on the soil conditions (Hailu et al., 2020). According to Mishra et al. (2022), the soil that has been preserved through mixed cropping, cardamom-based agroforestry, and terrace farming has higher levels of organic carbon, magnesium, potassium, water holding capacity, and bulk density than non-conserved barren land.

3.4.6. Zikre watershed

The Zikre watershed is located in Ethiopia’s northwestern Amhara region. It was possible to draw the conclusion from the study that slope classes, land use kinds, and land management techniques all considerably affect the soil’s physicochemical attributes (Table A3 & A5). It was clear that changing from natural forest to other land uses had a negative impact on the physical and chemical properties of the soil. The overall qualities of the soils under the cultivated land were inferior to the soil’s attributes of the adjacent natural forest, plantation forest, and grazing lands. Thus, according to Selassie et al. (2015), integrated land management practices are the best means of lowering soil erosion and raising soil fertility on farmed fields. Jiru and Wegari (2022) found a similar finding, stating that integrating physical structure with biological measurements significantly boosts agricultural output compared to physical structure alone. Therefore, to boost the advantages of SWC practices in terms of soil physicochemical properties and crop production, adopting the combined physical structure with the biological measure is suitable as an optional approach.

3.4.7. Anjeni watershed, northwest Ethiopia

One of the six SCRP locations in the highlands of Ethiopia is the Anjeni watershed. The purpose of the study was to evaluate the fanya juu terraces and grass strips that were built as part of a pilot project in 1984 and are still in use today. Teff, barley, and maize were the crops evaluated. The economic advantages with and without terraces were determined using cost-benefit analyses (Table A6). The findings showed that crop productivity had increased as a result of soil and water conservation. Teff produced an average yield of 0.95 t ha⁻¹ (control: 0.49), barley produced 1.86 t ha⁻¹ (control: 0.61), and maize produced 1.73 t ha⁻¹ (control: 0.77). In contrast to the practices on farms without terraces, farmers now produce barley on terraced fields for two crop seasons each year. Food security and household incomes had both increased, and soil erosion had significantly decreased. In order to double the initial area under the soil conservation pilot project, several farmers embraced terracing, this improved environmental conservation in the watershed (Adgo & Teshome, 2014).

The study demonstrated how soil and water conservation at the Anjeni watershed greatly boosted crop yields and soil quality over the long run. The conservation structures at the lower edges of the terraces catch soil nutrients that are transferred from the upper parts of the terrace and keep them there, creating a noticeable contrast between the lower and upper parts. Nitrogen, phosphorus, and soil organic matter are the primary limiting variables for agricultural output in Ethiopia’s high-rainfall regions, such as Anjeni. Fortunately, the farm’s soil properties have greatly improved as a result of terraces, improving agricultural yields. This supports the findings of Qiang and Han (2021), who found that a soil environment on a terrace used for a long time would enhance the soil’s capacity to accumulate carbon and nitrogen. Without soil conservation structures, stored nutrients will be flushed from the farm and carried to neighboring ecosystems, primarily water bodies, adding to the nation’s costs (Somasundaram et al., 2020). The fertility condition of the soil varied significantly across the watershed’s landscapes (slopes and altitude), with the steep slopes that may be linked to historic erosion (prior to the implementation of conservation) showing the lowest fertility.

3.5. Technical evaluation of implemented soil conservation in Ethiopia

When Ethiopia’s community-based watershed management method was being established, the ministry of agriculture (MOA) recommended soil conservation based on agro ecology (Desta et al., 2005). Different soil conservation initiatives have been carried out across the nation through community mobilization based on the recommended conservation practices.

3.5.1. Case 1: Southern nations, nationalities and peoples’ regional state, south Ethiopia

Different soil conservation techniques were used, according to a study done in the Southern Nation, Nationalities, and Peoples of Ethiopia. Four zones from the area (Sidama, Kambata Tambaro, Wolayita, and Dawro) as well as two districts from each zone were purposefully chosen by the writers for the study. Soil bunds, Fanya juu, Trenches, micro basins, stone bunds, and cut off drains, among other soil conservation techniques, were built in the chosen watershed. In this instance, a microstructure was built for a tree planting. According to the guidelines, the suitability of the chosen structures ranges from slightly acceptable to appropriate.

The survey found that each kebele under study had an effective organizational framework that aids in educating and organizing the population for active watershed management activities. The kebele development teams are in charge of encouraging participation in campaign efforts and holding absentees accountable. This crew made a substantial contribution towards achieving the results that were shown. These outcomes, including well-established tree and shrub plantations, rehabilitated lands, fodder grass established on bunds, and the planting of species that increase soil fertility, like pigeon pea, can be viewed as excellent land management lessons that can inspire the general public to participate in such labor-intensive tasks. Most of the species that were planted on the degraded soils in the micro-watersheds under study were adapted to the agro-ecology and unfavorable site conditions. However, technical and planting time considerations are required due to the poor survival seen in some micro-watersheds. The majority of micro-watersheds had suitable structure selection, design, construction, and spacing. However, in some micro-watersheds, mistakes such as inadequate stone bund foundations, bunds with small berms, insufficient channel depths, and excessively long bunds that block access to farms must be fixed. Additionally, there are numerous areas where the effort to restore the damaged or sediment-filled structures is subpar and needs attention, which will affect how well they will fare in the long run (Wolancho, 2015).

3.5.2. Case 2: Maego watershed, north Ethiopia

The study was carried out in Tigray, Ethiopia’s Maego watershed, Negash village, and Kilte Awulaelo district. The study area has three distinct agro-climatic zones: 15% Dega (highland), 82% Woyna Dega (mid land), and 3% Kolla (low land). The area’s elevation ranges from 1400 m to 2250 m above sea level. The region’s typical annual rainfall is roughly 450 mm, and the average daily air temperature fluctuates between 15 and 30 degrees Celsius (Abesha, 2014).

This watershed was chosen for the study because it was representative in terms of the use of intense SWC. Stone bunds, trenches, bench terraces, stone bund + trench, hillside terraces, and gully treatment with gabion check dams are some of the main physical SWC structures built on farmlands, closure areas, and grazing land in the watershed. In the watershed, work on building stone bunds and hillside terraces began in 1998, whereas bench terraces and deep trenches were first built seven years earlier. Even though food for work programmes built the majority of the SWC facilities in the watershed, the local people also provided free labor. The construction of SWC measures was mostly done to preserve degraded areas, restore them, and boost agricultural productivity. Even though physical SWC measures received more focus, biological SWC measures such as elephant grass restoration of gullies and the planting of E. camaldulensis, Acacia saligna, and Sesbania sesban tree seedlings were initiated in the watershed. Many tree seedlings were reportedly planted as biological defenses in the watershed, but due to moisture stress and animal free grazing, their survivability was limited.

At the beginning of watershed management, more emphasis was placed on physical SWC measures. Many tree seedlings were planted as biological measures in the watershed, but their survival was limited due to free grazing by cattle and other factors. The young SWC buildings had the largest documented sediment accumulation behind them. Some old structures have been destroyed and silted up as a result of runoff covering them. Some SWC structures, particularly the older ones, have not been built to the required technical standards in terms of height and width. Additionally, there are restrictions on the spacing of the structures due to site-specific biophysical characteristics. Some of the buildings are built narrower than the guidelines, while others are built with wider spacing than is advised. According to the local farmers, knowledge and ability gaps, free grazing, and a focus on coverage areas rather than technical quality were the main causes of the failure to implement parts of the SWC structures based on the technical criteria. Additionally, the buildings on the common lands are not maintained (Dimtsu, 2018)

4. Summary and conclusion

Our existence is based on natural resources, primarily soil, water, and plants, on which humans depend for everything from food to shelter to clothing. With assistance from foreign organizations, the Ethiopian government has given environmental restoration and conservation efforts a lot of attention. In order to prevent erosion and the resulting nutrient loss, the use of soil conservation structures is promising. Past safety net programme watershed management techniques were merely physical soil conservation techniques that couldn’t safeguard the soil and water alone. To prevent soil loss due to water erosion, the barrier approach and the cover approach have been developed. To block runoff and the sediment, it carries, barriers made of semi-permeable materials like grass strips and hedgerows are employed in conjunction with soil conservation techniques like terraces, Fanya juu, and Soil bund. The cover strategy often uses plant materials to slow down the flow volume and runoff velocity. Numerous studies demonstrate that the soil’s physicochemical qualities and agricultural output are improved by the structure’s preservation of the land.

Currently, community-based watershed management is used to adopt soil conservation strategies. This strategy is regarded as similar to community involvement and community-centered strategies. Agroecological, multidisciplinary, and multi-stakeholders integrated watershed management tactics are used in this new strategy to improve natural resources. Therefore, public participation is crucial for successful and sustainable watershed management. Accordingly, the nation’s Ministry of Agriculture proposed using agroecological soil conservation measures. As a result, conservation measures, including biological and physical soil conservation measures, were put into place in various watersheds around the nation. Numerous studies on their effects have also been done, and the results demonstrate a considerable impact on agricultural output and soil fertility.

Additionally, earlier efforts have paved the way for current advancements in methods to better natural resources, particularly soil resources, for greater public knowledge of the negative effects of land degradation, for improved involvement of stakeholders, and for improved links. Additionally, although there is still much to be done, stakeholder collaboration and community participation have increased significantly this time.

Some gab was found, according to the technical evaluation research. The physical soil conservation structures/layout restrictions and the chosen biological soil conservation were not adequate in some watersheds. Poor stone bund foundations, bunds with narrow berms, shallow channel depth, and too long bunds without enough room for land users to move caused problems with the physical conservation of soil. Other issues included free grazing in some areas, attention being paid to coverage area rather than technical quality, poor maintenance of the structures on communal lands, etc. In the watershed, tree seedlings have been planted as a biological measure; however, due to moisture stress and animals grazing freely, their survival rates were low. Therefore, the seedling survival rate and planting time are two of the bottlenecks for biological soil conservation.

5. Recommandation

The management of natural resources, especially Ethiopia’s soil resources, can greatly benefit from soil conservation. Many authors who researched the nation’s impact on soil conservation published various recommendations. Nevertheless, during the evaluation, an unacted-upon but crucial point was discovered. Therefore, when implementing and promoting soil conservation techniques, the following activities should be taken into account:

• To reach the desired goal, physical and biological soil conservation, as recommended by agroecology, should be practiced.

• To improve technical quality, they should receive instruction on the layout of conservation measures and extensive capacity-building about the layout of structures.

• For a quick result, integration of conservation practices (both biological and physical) is crucial. However, depending on the guidelines, the practices should be carried out at the proper time and place.

• The research system must contribute to the ongoing development of soil conservation technology. Researchers should test suitable physical and biological soil conservation techniques. Involved organizations or researchers should also adapt trees and grasses to the area for conservation purposes.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Dilnesa Bayle

Dilnesa Bayle Azmera, the first author of this review, is a lecturer and researcher in the Department of Natural Resource Management at Haramaya University. He completed a soil science master’s degree at Haramaya University in Ethiopia. At Haramaya University, he has instructed a variety of soil courses. His research interests include managing soil fertility, increasing phosphorus availability in acidic soil, treating gully erosion, and turning various sources of bones into fertilizer.

Kelemu Muluye

Kelemu Muluye, the second author of this review, is a lecturer and researcher in the School of Animal Science and Range Ecology. He is doing research on phosphorus-solubilizing microorganisms.

Appendix

Table A1. Effects of SWC measures on selected soil physicochemical properties and crop yield, Debre Yacob micro-watershed

Treatments	Sand (%)	Silt (%)	Clay (%)	Texture class	Bulk Density (gcm^−3)
Control(non-conserved plots)+ gentle slope (CA)	16.95	19.61	63.44	Clay	1.77
Control(non-conserved plots)+ moderate slope (CB)	12.95	17.28	69.77	Clay	1.55
Bund+ Sesbania sesban + gentle slope (SA)	21.28	25.28	53.44	Clay	1.64
Bund+ Sesbania sesban + moderate slope (SB)	20.28	21.95	58.11	Clay	1.54
Bund+ pigeon pea+ gentle slope (PA)	20.28	23.61	54.77	Clay	1.35
Bund+ pigeon pea+moderate slope (PB)	19.95	23.28	56.77	Clay	1.62
LSD (0.05)	0.02*	0.0**	0.01**		0.01**
CV	19.22	19.4	12.10		16.20

C.V = Coefficient of variation; LSD = Least significant difference; ** = Significant at the 0.01 level; * = Significant at the 0.05 level.

Table

Treatments	pH	OM (%)	TN (%)	AVP(ppm)	CEC (cmol+/kg)
Non-conserved plots+ gentle slope(NCGS)	6.36	2.40	0.09	3.38	27.31
Non-conserved plots+ moderate slope(NCMS)	6.03	2.63	0.11	3.45	31.27
Bund+ Sesbania sesban + gentle slope(BSGS)	6.49	2.48	0.12	3.72	30.79
Bund+ Sesbania sesban + moderate slope(BSMS)	6.17	2.74	0.11	3.19	32.01
Bund+ pigeon pea +gentle slope(BPMS)	6.66	3.01	0.11	3.16	30.17
Bund+ pigeon pea +moderate slope(BPMS)	6.10	2.66	0.11	4.20	28.56
LSD (0.05)	0.00**	0.01**	0.03*	0.04*	0.01**
SD	0.18	0.38	0.03	1.28	3.88
SEM (±)	0.17	0.22	0.02	0.74	2.24
CV	2.81	15.01	28.62	34.90	12.81

C.V = Coefficient of variation; LSD = Least significant difference; ** = Significant at the 0.01 level; * = Significant at the 0.05 level.

Table

	Crop Yield(Kg/ha)
Treatments	Maize	Finger Millet
Control (non-conserved)	2946^b	1200^b
Bund stabilized with Sesbania sesban	4344^a	1716^a
Bund stabilized with pigeon pea	4484^a	1856^a

Note: Means within column followed by different letters are significantly different (p < 0.05).

Table A2. Effect of conservation practices on soil physicochemical properties, growth, yield component and yield of wheat in cultivated lands of Bashe micro-watershed

Conservation practices	BD (gcm^−3)	Sand (%)	Silt (%)	Clay (%)	Textural class	pH-H2O	Soil OC (%)	Soil-OM (%)	AVP(mgkg^−1)
Non-conserved	1.10	22.66	32.00	45.33	Clay	5.87	1.34	2.32	8.06
Physical SWC-2 year	1.07	24.00	29.00	47.00	Clay	6.07	1.68	2.90	11.74
Integrated SWC-2 year	1.06	21.33	34.33	44.33	Clay	6.39	1.42	2.45	14.57
Physical SWC-5 year	1.06	21.33	40.33	38.33	Clay loam	6.33	1.61	2.78	20.80
Integrated SWC-5 year	0.96	23.00	32.33	44.66	Clay	6.60	1.74	3.00	25.23
CV (%)	3.75	17.24	15.75	14.66	–	10.68	18.95	18.89	78.12

CV = coefficient of variation.

Table

Conservation practices	Plant height (cm)	Total tiller (No. m−2)	Productive tiller (No. m−2)	Biomass yield (t ha−1)	Straw (t ha−1)	Spike length (cm)	Grain yield (t ha−1)	Thousand seed weight (g)
Non-conserved	67.20^c	348.17^c	309.87^c	5.93^c	3.30^c	4.20^c	2.47^b	27.56^c
Physical SWC-2 year	72.10^b	396.30^bc	365.40^b	6.67^bc	4.16^b	4.66^bc	2.67^b	34.10b
Integrated SWC-2 year	72.56^b	451.87^ab	419.77^ab	7.63^b	4.83^b	5.66^b	2.78^b	36.50^b
Physical SWC-5 year	71.33^bc	482.73a	464.23^a	7.53^b	4.16^b	5.23^bc	3.33^b	34.60^b
Integrated SWC-5 year	89.90^a	476.53^a	469.13^a	11.00^a	6.73^a	8.56^a	4.27^a	49.73^a
^LSD0.05	4.17	56.014	55.383	1.3451	0.815	1.16	0.87	2.93
CV (%)	3.07	7.14	7.5	9.54	9.65	11.25	15.45	4.42

LSD = least significant differences, CV = coefficient of variation, NS = non-significant. means followed by the same letters indicates not significantly different at 5% level of significances.

Table A3. Effect of conservation terraces on soil organic carbon storage and soil properties, Minchet and Anjeni watershed

		Without conservation practice (Zikrie)		With conservation practice (Minchet)
Landscape positions	Relative location in sub-watershed	SOC (%)	Carbon stock (Mgha^—1in30-cmdepth)	SOC (%)	Carbon stock (Mgha^—1in30-cmdepth)
Toe slope	Upper	1·24	37·60	1·34	50·54
	Middle	2·42	80·01	1·42	60·67
	Lower	2·06	81·94	1·51	54·46
	Average	1·90	66·52	1·42	55·22
	SD	0·95	33·33	0·44	16·65
Foot slope	Upper	0·83	31·79	1·12	42·67
	Middle	2·15	83·01	1·51	51·94
	Lower	1·02	36·58	1·96	81·81
	Average	1·33	50·46	1·53	58·81
	SD	0·69	26·21	0·61	25·88
Back slope	Upper	1·27	40·57	2·16	80·61
	Middle	1·77	63·45	2·00	72·34
	Lower	1·03	36·28	2·44	90·57
	Average	1·36	46·77	2·20	81·17
	SD	0·78	28·29	0·76	25·54
Shoulder slope	Upper	2·00	69·95	1·66	56·37
	Middle	1·43	51·72	2·37	79·48
	Lower	1·52	55·31	1·02	40·52
	Average	1·65	58·99	1·68	58·79
	SD	0·59	20·82	0·85	27·13
Crest slope	Upper	1·50	49·50	2·38	74·76
	Middle	2·29	75·55	1·51	52·95
	Lower	2·18	77·48	1·01	33·44
	Average	1·99	67·51	1·63	53·72
	SD	0·87	36·76	0·70	21·67
Average	Upper	1·37	45·88	1·73	60·99
	Middle	2·01	70·75	1·77	63·47
	Lower	1·56	57·52	1·59	60·16
	Average	1·65	58·05	1·70	61·54
	SD	0·78	28·96	0·71	24·64

SD = standard deviation.

Table

		Without conservation practice(Zikrie)					With conservation practice (Minchet)
Landscape positions	Relative location in sub-watershed	Bulk density (gcm^—3)	Sand (%)	Silt (%)	Clay (%)	Textural class	Bulk density (gcm^—3)	Sand (%)	Silt (%)	Clay (%)	Textural class
Toe slope	Upper	1·01	20·56	28·28	51·16	C	1·26	15·89	25·95	58·16	C
	Middle	1·10	20·38	35·28	44·34	C	1·43	23·89	27·95	48·16	C
	Lower	1·33	27·56	26·28	46·16	C	1·21	17·56	24·28	58·16	C
	Average	1·15	22·83	29·95	47·22	C	1·30	19·12	26·06	54·83	C
	SD	0·15	10·15	6·89	12·91		0·12	5·85	5·66	9·77
Foot slope	Upper	1·28	13·56	24·28	62·16	C	1·27	19·77	21·95	58·28	C
	Middle	1·29	31·56	36·28	32·16	CL	1·15	23·29	28·88	47·83	C
	Lower	1·20	20·38	32·28	47·34	C	1·39	22·56	28·28	49·16	C
	Average	1·25	21·83	30·95	47·22	C	1·27	21·87	26·37	51·76	C
	SD	0·17	9·14	7·09	13·77		0·11	8·00	4·99	9·11
Back slope	Upper	1·06	19·56	24·28	56·16	C	1·24	23·47	30·78	45·75	C
	Middle	1·20	20·44	25·95	53·61	C	1·21	22·74	27·68	49·58	C
	Lower	1·17	23·89	25·95	50·16	C	1·24	27·56	25·28	47·16	C
	Average	1·15	21·52	25·39	53·31	C	1·23	24·59	27·91	47·50	C
	SD	0·08	6·46	2·91	8·78		0·08	6·82	5·59	10·20
Shoulder	Upper	1·17	23·56	26·28	50·16	C	1·13	21·11	28·61	50·28	C
slope	Middle	1·21	14·38	27·28	58·34	C	1·12	25·11	27·95	46·95	C
	Lower	1·21	16·56	28·28	55·16	C	1·32	20·56	19·28	60·16	C
	Average	1·20	18·17	27·28	54·55	C	1·19	22·26	25·28	50·46	C
	SD	0·15	5·48	4·73	7·33		0·12	4·02	3·90	6·29
Crest slope	Upper	1·10	22·44	36·61	40·95	C	1·05	29·56	25·28	45·16	C
	Middle	1·10	26·56	32·28	41·16	C	1·17	24·56	22·61	52·83	C
	Lower	1·18	25·38	28·28	46·34	C	1·10	24·56	25·28	50·16	C
	Average	1·13	24·46	32·39	42·82	C	1·11	26·23	24·39	49·38	C
	SD	0·15	3·14	5·09	4·05		0·06	3·88	6·65	9·24
Average	Upper	1·12	19·94	27·95	52·12	C	1·19	21·96	26·51	51·53	C
	Middle	1·18	22·66	31·41	45·92	C	1·21	23·92	27·01	49·07	C
	Lower	1·22	22·75	28·21	49·03	C	1·25	22·56	24·48	52·96	C
	Average	1·17	21·78	29·19	49·02	C	1·22	22·81	26·00	51·18	C
	SD	0·14	7·00	5·78	10·20		0·12	6·32	5·05	9·02

Table A4. Effect of fanya juu on soil physicochemical properties, Ambo district, Goromti watershed

		Conservation practice with age
Variable	Slope gradient	Control	F-juu5	F-juu10	Over all
	3–15	40.42 ± 2.39	36.0 ± 2.72	30.6 ± 2.96	35.67 ± 1.95^a
Sand (%)	15–30	39.7 ± 2.31	39.04 ± 0.94	38.2 ± 0.37	38.93 ± 0.75^ab
	>30	44.42 ± 0.57	38.6 ± 1.27	49.3 ± 8.76	44.11 ± 2.99^b
	Over all	41.5 ± 1.23^a	37.9 ± 1.03^a	39.4 ± 3.92^a
	3–15	34.6 ± 1.25	32.5 ± 1.36	22.5 ± 8.14	29.9 ± 3.05a
Silt (%)	15–30	34.4 ± 0.33	30.3 ± 1.28	35.1 ± 1.28	33.3 ± 0.91a
	>30	33.0 ± 2.47	37.2 ± 0.98	27.7 ± 11.74	32.6 ± 3.74^a
	Over all	34.0 ± 0.84^a	33.4 ± 1.19^a	28.41 ± 4.3^a
	3–15	25.0 ± 3.02	31.5 ± 1.35	43.9 ± 11.12	33.5 ± 4.35^a
Clay (%)	15–30	26.1 ± 4.25	30.6 ± 0.49	28.3 ± 0.71	28.3 ± 1.00^ab
	>30	22.6 ± 1.89	24.2 ± 1.20	26.5 ± 1.93	24.4 ± 1.02^b
	Over all	24.7 ± 1.35^a	28.8 ± 1.27^a	33.0 ± 4.28^a
	3–15	1.07 ± 0.01	1.06 ± 0.02	1.04 ± 0.04	1.06 ± 0.02^b
Bd (g/cm^3)	15–30	1.12 ± 0.04	1.11 ± 0.02	1.09 ± 0.02	1.10 ± 0.02^a
	>30	1.16 ± 0.01	1.16 ± 0.02	1.16 ± 0.03	1.09 ± 0.02^a
	Over all	1.12 ± 0.02^a	1.10 ± 0.02^a	1.09 ± 0.02^a

Means within rows followed by different letters are significantly different (p < 0.05) with respect to treatment and slope gradient.

Table

		Conservation practice with age
Variable	Slope gradient	Control	F-juu5	F-juu10	Over all
	3–15	2.24 ± 0.18	2.38 ± 0.08	2.37 ± 0.05	2.35 ± 0.06a
SOC (%)	15–30	1.94 ± 0.09	2.31 ± 0.06	2.18 ± 0.07	2.15 ± 0.07a
	>30	1.68 ± 0.07	1.92 ± 0.03	1.94 ± 0.24	1.86 ± 0.08b
	Over all	1.96 ± 0.10b	2.21 ± 0.08a	2.17 ± 0.1ab
	3–15	0.19 ± 0.019	0.24 ± 0.03	0.28 ± 0.05	0.24 ± 0.02a
TN (%)	15–30	0.16 ± 0.024	0.20 ± 0.05	0.19 ± 0.04	0.20 ± 0.01ab
	>30	0.17 ± 0.04	0.19 ± 0.02	0.24 ± 0.07	0.18 ± 0.02b
	Overall	0.17 ± 0.009b	0.21 ± 0.0.01ab	0.24 ± 0.01a
	3–15	11.86 ± 0.41	10.06 ± 0.56	8.43 ± 0.70	10.11 ± 0.57ab
C: N (%)	15–30	11.92 ± 0.69	12.05 ± 1.57	11.46 ± 1.06	11.81 ± 0.59a
	>30	10.49 ± 2.22	9.56 ± 0.46	8.16 ± 0.98	9.44 ± 0.79b
	Over all	11.42 ± 0.72a	10.58 ± 0.62a	9.35 ± 0.70a

Means within rows followed by different letters are significantly different (p < 0.05) with respect to treatment and slope gradient.

Table

		Conservation practice with age
Variable	Slope gradient	Control	F-juu5	F-juu10	Over all
	3–15	5.71 ± 0.063	5.80 ± 0.038	5.80 ± 0.115	5.77 ± 0.04a
pH	15–30	5.41 ± 0.072	5.25 ± 0.112	5.79 ± 0.043	5.48 ± 0.08b
	>30	5.57 ± 0.052	5.42 ± 0.072	5.67 ± 0.040	5.55 ± 0.04b
	Over all	5.56 ± 0.05b	5.49 ± 0.09b	5.75 ± 0.04a
	3–15	0.07 ± 0.003	0.05 ± 0.003	0.07 ± 0.003	0.061±.004ab
EC(ms/cm)	15–30	0.05 ± 0.008	0.05 ± 0.003	0.06 ± 0.00	0.05 ± 0.003b
	>30	0.07 ± 0.006	0.07 ± 0.01	0.06 ± 0.001	0.06 ± 0.004a
	Over all	0.062 ± 0.005a	0.056 ± 0.004a	0.062 ± 0.002a
	3–15	33.89 ± 2.61	37.12 ± 4.15	33.30 ± 2.17	34.77 ± 1.66a
CEC(cmolc/kg)	15–30	31.21 ± 2.01	31.04 ± 2.98	30.38 ± 1.35	30.88 ± 1.12a
	>30	29.97 ± 2.44	30.66 ± 1.48	28.65 ± 1.78	29.77 ± 1.02a
	Over all	31.69 ± 1.32a	32.95 ± 1.86a	30.78 ± 1.13a
	3–15	28.48 ± 10.69	18.27 ± 4.28	16.81 ± 2.62	25.10 ± 4.81a
AVP(gm)	15–30	29.35 ± 8.84	31.37 ± 16.20	22.84 ± 5.47	27.85 ± 5.70a
	>30	17.20 ± 4.77	20.74 ± 1.32	45.31 ± 13.97	23.84 ± 5.67a
	Over all	25.01 ± 4.67a	23.47 ± 5.25a	28.33 ± 6.17a
	3–15	1087.70 ± 391.	553.8 ± 56.47	753.5 ± 34.4	798.35 ± 138.64a
Av K(ppm)	15–30	914.19 ± 206.2	786.9 ± 63.1	616.5 ± 11.5	772.57 ± 75.81a
	>30	1057.2 ± 302.9	1297.7 ± 35.6	938.3 ± 84.6	1097.7 ± 105.58a
	Over all	564.08 ± 21.72	540.06 ± 32.72	618.36 ± 34.14

Means within rows followed by different letters are significantly different (p < 0.05) with respect to treatment and slope gradient.

Table

		Conservation practice with age
Variable	Slope gradient	Control	Fjuu5	Fjuu10	Over all
	3–15	0.46 ± 0.07	0.21 ± 0.04	0.23 ± 0.02	0.30 ± 0.05a
Na (cmolc/kg)	15–30	0.48 ± 0.10	0.240±.05	0.38 ± 0.04	0.36 ± 0.05a
	>30	0.53 ± 0.18	0.49 ± 0.02	0.350.03	0.46 ± 0.06a
	Over all	0.49 ± 0.06a	0.32 ± 0.05b	0.32 ± 0.03b
	3–15	3.25 ± 0.75	1.46 ± 0.19	1.54 ± 0.06	2.09 ± 0.37a
K(cmolc/kg)	15–30	2.22 ± 0.16	1.70 ± 0.15	2.07 ± 0.17	2.001 ± 0.11a
	>30	2.83 ± 0.95	2.89 ± 0.08	2.19 ± 0.11	2.64 ± 0.30a
	Overall	2.77 ± 0.38a	2.02 ± 0.23a	1.94 ± 0.12a
	3–15	12.60 ± 2.43	13.65 ± 1.55	14.46 ± 2.08	13.57 ± 1.06a
Ca(cmolc/kg)	15–30	11.83 ± 0.32	11.25 ± 1.32	15.27 ± 2.02	12.79 ± 0.94a
	>30	12.56 ± 1.52	13.89 ± 1.81	15.55 ± 0.50	14.01 ± 0.82a
	Overall	12.33 ± 0.84a	12.94 ± 0.89a	15.1 ± 0.87a
	3–15	7.40 ± 2.66	10.69 ± 2.11	13.02 ± 2.28	10.37 ± 1.44a
Mg(Cmol(+)/kg)	15–30	8.65 ± 1.01	10.37 ± 3.59	10.95 ± 1.88	9.10 ± 1.25a
	>30	6.59 ± 1.57	5.19 ± 2.15	11.23 ± 0.86	7.01 ± 1.22a
	Over all	7.55 ± 0.99a	8.75 ± 1.62a	11.73 ± 0.95a

Means within rows followed by different letters are significantly different (p < 0.05) with respect to treatment and slope gradient.

Table A5. Effect of management practices on selected soil physicochemical properties Zikri watershed

Management Practices	PH (H2O)	TN (%)	AVP (mg kg^−1)	OM (%)	CEC (Cmol (+) kg^−1)	Bd (g cm^−3)
Manure and soil bund	6.36^a	0.29^a	18.41^a	5.88^a	31.10^a	1.14^c
Bund	5.72^c	0.14^c	4.91^c	2.77^c	29.26^b	1.26^ab
Manure	6.03a	0.21^b	10.13^b	4.50^b	30.80^ab	1.24^b
No manure and no soil bund	5.63^c	0.14^c	2.53^c	2.63^c	25.02^c	1.30^a

Mean in a column followed by the same letter are not significantly difference at p ≤ 0.05.

Table A6. Cost—benefit analysis of teff, barley and maize as affected by terraced and un-terraced fields, Dembecha district, Anjeni watershed

Crop/treatment	Revenue US $ha^−1	Expenses US $ha^−1	Net profit US $ha^−1
Teff
Terraced	292.6	271.7	20.9
Un-terraced	144.1	256.3	−112.2
Barley
Terraced	382.3	197.1	185.2
Un-terraced	98.5	139.6	−41.1
Maize
Terraced	245.7	280.2	−34.5
Un-terraced	102.2	203.0	−100.8

Effect of Terraces on selected soil properties, Dembecha district, Anjeni watershed

Table

Terrace zone	pH	OM (%)	TN (%)	AVP	Exchangeable bases (Cmol(+)/kg)				SEB	CEC (Cmol(+)/kg)	PBS (%)
					Na	K	Ca	Mg
Deposition	5.7	3.05	0.20	7.79	0.09	1.44	8.49	2.00	12.02	21.57	58.33
Loss	6.0	1.74	0.15	6.83	0.17	1.27	8.38	2.12	11.94	20.35	55.66
Student’st-test	ns	**	*	ns	ns	ns	ns	ns	ns	*	*

**Significant at p ≤ 0.01;*Significant at p ≤ 0.05; ns = non-significant at p ≤ 0.05; SEB = Sum of Exchangeable Bases; PBS = Percent Base Saturation.

Effect of Terraces on yield and yield components of Maize and Wheat, Dembecha district, Anjeni watershed

Table

		Wheat			Maize
Terrace zone	Grain yield(kg/ha)	Biomass yield(kg/ha)	Plant Height(m)	Grain yield (kg/ha)	Biomass yield(kg/ha)	Plant height(m)
Deposition	1077.2^a	5208.3^a	0.64^a	2695.1^a	17125^a	2.38^a
Middle	759.9^b	4183.3^b	0.59^a	1685.9^b	10250^b	2.16^b
Loss	656.2^b	3491.7^c	0.52^b	1072.9^c	9292^b	2.08^b
CV (%)	22.5	12.8	10.56	36.1	21	7.48

Values in a column followed by the same letter are not statistically different at p ≤ 0.05.