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To tackle the problem of soil erosion and moisture stress, the government of Ethiopia introduced a yearly mass campaign where communities get together and implement various soil and water conservation (SWC) and water harvesting (WH) practices. Although the interventions are believed to have reduced soil erosion/sediment yield and enhanced surface and ground water, quantitative information on the impacts of various options at different scales is scarce. The objective of this study was to assess the impacts different land uses, SWC and WH interventions on water and suspended sediment yield (SSY) at plot and watershed scales in the central highlands of Ethiopia. Standard erosion plot experiments and hydrological stations were used to monitor the daily water and SSY during 2014 to 2017. The results show differences between treatments both at plot and watershed scales. Runoff and soil loss were reduced by an average 27 and 37%, respectively due to SWC practices at the plot level. Overall, SWC practices implemented at the watershed level reduced sediment yield by about 74% (in the year 2014), although the magnitude of sediment reduction due to the SWC interventions reduced over time. At both scales it was observed that as the number of years since SWC measures have been in place increased, their effectiveness declined due to the lack of maintenance. This study also revealed that extrapolating of plot data to watershed scale causes over or under estimation of net erosion.

Land restoration is considered to be the remedy for 21st century global challenges of land degradation. As a result, various land restoration and conservation efforts are underway at different scales. Ethiopia is one of the countries with huge investments in land restoration. Tremendous land management practices have been implemented across the country since the 1970s. However, the spatial distribution of the interventions has not been documented, and there is no systematic, quantitative evidence on whether land restoration efforts have achieved the restoration of desired ecosystem services. Therefore, we carried out a meta-analysis of peer-reviewed scientific literature related to land restoration efforts and their impacts in Ethiopia. Results show that most of the large-scale projects have been implemented in the highlands, specifically in Tigray and Amhara regions covering about 24 agroecological zones, and land restoration impact studies are mostly focused in the highlands but restricted in about 11 agroecological zones. The highest mean effect on agricultural productivity is obtained from the combination of bunds and biological interventions followed by conservation agriculture practices with 170% and 18% increases, respectively. However, bunds alone, biological intervention alone, and terracing (fanya juu) reveal negative effects on productivity. The mean effect of all land restoration interventions on soil organic carbon is positive, the highest effect being from “bunds + biological” (139%) followed by exclosure (90%). Reduced soil erosion and runoff are the dominant impacts of all interventions. The results can be used to improve existing guidelines to better match land restoration options with specific desired ecosystem functions and services. Although the focus of this study was on the evaluation of the impacts of land restoration efforts on selected ecosystem services, impacts on livelihood and national socioeconomy have not been examined. Thus, strengthening socioeconomic studies at national scale to assess the sustainability of land restoration initiatives is an essential next step.

Environmental degradation and climate change are key current threats to world agriculture and food security and human–induced changes have been significant driving forces of this global environmental change. An important component is land degradation which results in a diminished soil organic carbon (SOC) stock with concomitant loss of soil condition and function. Land management to improve soil organic matter content, condition and productivity is therefore a key strategy to safeguard agricultural production, food supply and environmental quality. Soil organic carbon sequestration through the use of plant species with high photosynthetic efficiency, deep roots and high biomass production is one important strategy to achieve this. Tropical pastures, which are adapted to a wide range of environmental conditions have particular potential in this regard and have been used extensively for land rehabilitation. Tropical pastures also have advantages over trees for biomass and carbon accumulation due to their rapid establishment, suitability for annual harvest, continual and rapid growth rates. In addition, tropical pastures have the potential for SOC storage in subsoil horizons due to their deep root systems and can be used as biomass energy crops, which could further promote their use as a climate change mitigation option. Here we aimed to review current knowledge regarding the SOC storage potential of tropical grasses worldwide and identified knowledge gaps and current research needs for the use of tropical grasses in agricultural production system.

This study was conducted on Eutric Nitisols of Holeta Agricultural Research Center (HARC) in the humid highlands of Ethiopia. The main objective was to assess the effect of tillage and crop residue management on runoff, soil loss and wheat (Triticum aestivum L.) yield over three years (2009–2011). Nine treatments combining three tillage practices (zero, minimum and conventional tillage) and three rates of crop residue (0, 1 and 2 t ha−1 yr−1) were used. The experiment was laid out in a Randomized Complete Block Design with three replications. The result showed that average runoff was significantly higher (332 mm) in zero tillage without crop residue (T0C0) and lower (198 mm) in conventional tillage with 2 t ha−1 yr−1 crop residue (T2C2). The average soil loss was lower (16 t ha−1 yr−1) in zero tillage with 2 t ha−1 yr−1 crop residue (T0C2) and higher (30 t ha−1 yr−1) in conventional tillage without crop residue (T2C0). Although, zero and minimum tillage treatments reduced soil loss significantly as compared with conventional tillage practices, the annual soil loss (16 t ha−1 yr−1) is still much higher than the tolerable soil loss for the Ethiopian highlands (2–10 t ha−1 yr−1). This suggests the need to complement zero and minimum tillage practices with physical soil and water conservation practices. On average, highest grain (2 t ha−1) and biomass (6 t ha−1) yields of wheat were recorded in T2C2 while the lowest grain and biomass yields were recorded in T0C0. Based on the above observation, we argue that conventional tillage combined with sufficient crop residue is the most appropriate approach to reduce runoff and increase wheat yield in the short-term. However, zero tillage practices with crop residue are effective to reduce soil loss. As this study was based on results of three years data, long-term study is needed to figure out the long-term impacts of tillage and crop residue management in Ethiopia.

An enormous effort is underway in Ethiopia to address soil erosion and restore overall land productivity. Modelling and participatory approaches can be used to delineate erosion hotspots, plan site- and context-specific interventions and assess their impacts. In this study, we employed a modelling interface developed based on the Revised Universal Soil Loss Equation adjusted by the sediment delivery ratio to map the spatial distribution of net soil loss and identify priority areas of intervention. Using the modelling interface, we also simulated the potential impacts of different soil and water conservation measures in reducing net soil loss. Model predictions showed that net soil loss in the study area ranges between 0.4 and 88 t ha− 1 yr− 1 with an average of 12 t ha− 1 yr− 1. The dominant soil erosion hotspots were associated with steep slopes, gullies, communal grazing and cultivated areas. The average soil loss observed in this study is higher than the tolerable soil loss rate estimated for the highland of Ethiopia. The scenario analysis results showed that targeting hotspot areas where soil loss exceeds 10 t ha− 1 yr− 1 could reduce net soil loss to the tolerable limit (

Degradation of land, water and vegetation in the highlands of eastern Africa is on the increase in the face of the enforcement of natural resource management (NRM) policies and related by-laws. In this study, reasons behind the limited contribution of NRM by-laws in arresting degradation of natural resources in the highlands of Ethiopia, Tanzania and Uganda are presented, and opportunities to improve effectiveness identified. Using key informants’ interviews, focus group discussions, workshops, case studies and literature review, it is shown that inadequate community participation in the process of by-laws formulation and enforcement is the main reason for the ineffectiveness of most NRM by-laws in the three countries. When communities are fully involved in the process of NRM by-laws formulation and enforcement and both conventional and indigenous by-laws enforcement mechanisms are adopted, incidences of abuse of natural resources were reduced by as much as 50% in some of the study sites.

This study assesses the impact of the Productive Safety Net Program (PSNP) on farmers' investments in sustainable land management (SLM) practices in the Central Rift Valley (CRV) of Ethiopia. Primary data were collected using a structured and pre-tested questionnaire for a sample of 159 households (82 PSNP participants and 77 non-participants) in four kebeles (the lowest administrative unit in Ethiopia) of two weredas (districts). Using a cross-sectional household survey, propensity score matching (PSM) was used to assess the impact of PSNP on households' investments in soil erosion control and soil fertility management. The PSM results show that the control group of households (non-participants in PSNP) invested more in soil erosion control measures as compared to the treated group of households (participants in PSNP). On the contrary, however, the treated group of households significantly invested more in soil fertility management practices (e.g. inorganic fertilizer and compost) as compared to the control group of households. The negative impact of PSNP on households’ investments in soil erosion control in the treated group of farmers is related to their high labor investment in public works, which is not the case for the non-participants in PSNP. This implies that PSNP should pay more attention to capacity building and awareness raising, which requires a restructuring of the program that would benefit long-term and more sustainable impact on reducing food insecurity and enhancing natural resources in the CRV of Ethiopia.

Although there has been several efforts made to reduce land degradation and improve land productivity in Ethiopia, farmers’ investments in sustainable land management (SLM) remain limited. Nevertheless, the results regarding determinants of farmers’ investments in SLM have been inconsistent and scattered. Moreover, these factors have not been reviewed and synthesized. Hence this paper reviews and synthesizes past research in order to identify determinants that affect farmers’ investments in SLM practices and thereby facilitate policy prescriptions to enhance adoption in Ethiopia, East Africa and potentially wider afield. The review identifies several determinants that affect farmers’ investments in SLM practices. These determinants are generally categorized into three groups. The first group is those factors that are related to farmers’ capacity to invest in SLM practices. The results show that farmers’ investments in SLM practices are limited by their limited capacity to invest in SLM. The second groups of factors are related to farmers’ incentives for investments in SLM practices. Farmers’ investments in SLM are limited due to restricted incentives from their investments related to land improvement. The third groups of factors are external factors beyond the control of farmers. The review also shows that farmers’ capacities to invest in SLM and their incentives from investments have been influenced by external factors such as institutional support and policies. This suggests that creating enabling conditions for enhancing farmers’ investment capacities in SLM and increasing the range of incentives from their investment is crucial to encourage wide-scale adoption of SLM practices.

This paper provides details of soil and water conservation (SWC) investments in Ethiopia over the past 20 years. It presents SWC practices and estimates the level of SWC investments in different regions. The paper focuses on four principal agricultural regions: Amhara, Oromia, SNNPR and Tigray. Primary and secondary data were collected for the analysis, and consultations were conducted at regional levels. Primary data on diverse SWC practices, their numbers and areal extent were obtained from the archives of regional Bureaus of Agriculture (BoAs). The results of this study show that several projects involving significant financial investment have been implemented to reverse land degradation and improve land productivity in Ethiopia since the 1970s. The list of projects is not comprehensive due to a lack of documentation at all levels, but it does provide some insights into the scale of SWC investments and implementation. The projects analyzed in the four regions fall into the following categories: farmland management, hillside management and gully rehabilitation practices, including check dams and cut-off drains. The analysis shows that these practices involved both paid and unpaid labor, together representing an estimated investment of more than ETB 25 billion (or approximately USD 1.2 billion) per year over the past 10 years. It is clear that large investments have been made in SWC activities in Ethiopia. However, the outcomes in terms of impact on yield and livelihood benefits are yet to be fully understood. A comprehensive assessment is needed to measure the impact of SWC activities on farmers’ livelihoods and the environment. A key recommendation arising from the analysis is that more data and information are needed on the successes and failures of SWC practices, which will assist stakeholders to better guide and target future projects and investments. An additional recommendation is to consider the biophysical and financial impact of soil erosion, both on and off farm.

Small-scale irrigation (SSI) technologies can be useful not only to increase crop productivity and income but also as a viable adaptation practice to climate variability. A farm simulation model (FARMSIM) and data from selected SSI technologies piloted in northern Ghana under the ‘Feed the Future-Innovation Lab for Small Scale Irrigation’ (ILSSI) project were used to assess the economic feasibility of the SSI technologies and their potential to improve income and nutrition of smallholder farm households. Three dry season irrigated crops (onion, corchorus, amaranthus) grown under three agricultural water management regimes were analysed. Results show that adoption of the SSI technologies could increase the net farm profit by 154%–608% against the baseline depending on the ‘crop type - SSI technology’ combination. Nutrition levels also improved significantly as a result of the improvements in crop yields due to irrigation and use of complementary inputs. However, the results further reveal that the options that utilize capital-intensive SSI technologies such as solar-powered water pumps to grow high value cash crops are constrained by the high investment cost. Currently, farmers tend to choose low-cost SSI technologies such as a traditional watering-cans, which generate low economic returns. Improving access to credit or alternative financing schemes could mitigate the capital constraints and enable smallholders to gain more benefits from participating in market-oriented high-value irrigated production.

Despite decades of international attention to find solutions for the annual food shortages in Ethiopia, the problem still persists. This study, carried out in the Central Rift Valley (CRV) of Ethiopia, focuses on farmers׳ strategies to counter yield failures and food shortages. It reveals that farmers indeed perceive a decrease in crop productivity and food production over the last decades, and that they blame a decline in rainfall for this. As a consequence, farmers apply different strategies to cope with, and adapt to perceived rainfall shortages and related expected yield losses: i.e. they sell more livestock, they migrate elsewhere, they change their crops and agricultural practices, and they rely more heavily on food relief programs. However, an analysis of rainfall data in the CRV shows that rainfall characteristics (mainly annual rainfall total) have not changed over the last three decades. Moreover, according to analysis of official data, crop productivity per hectare in the CRV even shows a slight increase over the last decade. The interpretation of this result is not straightforward. The farmers׳ perception of a decline in crop productivity and rainfall may be related to (i) the increased demand to grow more crops to feed the rapidly growing population (hence, food availability per capita has declined), and (ii) the lower moisture availability for plant growth resulted from soil fertility decline and soil erosion. Nevertheless, additional empirical research is needed to figure out the root causes of food shortage and yield failure in the CRV of Ethiopia.

The use of co-investment activities to motivate farmers to carry out sustainable land management is increasingly recognized. Several co-investment efforts have been implemented to combat land degradation and increase agricultural production in the Ethiopian highlands. Nevertheless, these co-investment activities have not been documented. Moreover, the impacts of these activities have not been evaluated. This study presents a co-investment initiative for sustainable land management in the Galessa watershed in Ethiopia. It documents successful co-investment activities that trigger farmers to carry out land management practices, and assesses the impact of these activities on farmers’ land management investments. The most important co-investment activities that trigger farmers to invest in land management are co-investments in awareness creation, water provision, technology, and governance. Of these activities, co-investing in water provision is most successful, because it directly solves one of the basic needs of farmers in the watershed. Results reveal that the experimental group of farmers (participants in the co-investment initiative) – compared to the control group (nonparticipants) – invested significantly more in land management practices such as soil bunds, composting, and tree planting. This article concludes that use of multiple co-investment activities are crucial to trigger farmers to invest in land management in Ethiopia.

Traditional local institutions were studied in the highlands of Ethiopia and Tanzania to understand their role in natural resource management. Focus group discussions as well as individual interviews were conducted to identify the existing local institutions and their roles. Historical trend analyses were done to determine how the importance of local institutions has changed over the years. Results show that several local institutions with diverse objectives and varying levels of importance exist in the study sites. The article suggests ways in which local institutions can contribute to effective natural resource management for sustainable social and economic development of highland communities in eastern Africa.

The effects of soil bunds on runoff, losses of soil and nutrients, and crop yield are rarely documented in the Central Highlands of Ethiopia. A field experiment was set up consisting of three treatments: (i) barley-cultivated land protected with graded soil bunds (Sb); (ii) fallow land (F); and (iii) barley-cultivated land without soil bund (Bc). For 3?years (2007–2009), the effect of soil bunds on runoff, losses of soil and nutrients, and crop productivity was studied. Daily runoff and soil and nutrient losses were measured for each treatment using standard procedures while barley yield was recorded from the cultivated plots. The results showed that Sb brought about significant reduction in runoff and soil losses. Plots with Sb reduced the average annual runoff by 28?per cent and the average annual soil loss by 47?per cent. Consequently, Sb reduced losses of soil nutrients and organic carbon. However, the absolute losses were still high. This implies the need for supplementing Sb with biological and agronomic land management measures to further control soil erosion. Despite these positive impacts on soil quality, Sb do not increase crop yield. Calculated on a per-hectare basis, Sb even reduce crop yield by about 7?per cent as compared with control plots, which is entirely explained by the reduction of the cultivable area by 8·6?per cent due to the soil bunds. Suitable measures are needed to compensate the yield losses caused by the construction of soil bunds, which would convince farmers to construct these land management measures that have long-term beneficial effects on erosion control.

A growing concern about the limited impact of agricultural research and development on natural-resources management (NRM) and livelihoods in the highlands of East and Central Africa led to the establishment in 1995 of the African Highlands Initiative, with a mandate to develop methodologies for integrated NRM and institutionalise them in partner organisations. Emerging lessons show that a combination of innovative approaches is necessary for enhanced uptake of NRM practices. These approaches include working with strategic partners and multi-disciplinary teams; involving multiple stakeholders; adopting appropriate entry points based on farmers' priorities; and use of linked technologies with complementary and synergetic effects.

Research results published regarding the impact of soil and water conservation practices in the highland areas of Ethiopia have been inconsistent and scattered. In this paper, a detailed review and synthesis is reported that was conducted to identify the impacts of soil and water conservation practices on crop yield, surface run-off, soil loss, nutrient loss, and the economic viability, as well as to discuss the implications for an integrated approach and ecosystem services. The review and synthesis showed that most physical soil and water conservation practices such as soil bunds and stone bunds were very effective in reducing run-off, soil erosion and nutrient depletion. Despite these positive impacts on these services, the impact of physical soil and water conservation practices on crop yield was negative mainly due to the reduction of effective cultivable area by soil/stone bunds. In contrast, most agronomic soil and water conservation practices increase crop yield and reduce run-off and soil losses. This implies that integrating physical soil and water conservation practices with agronomic soil and water conservation practices are essential to increase both provisioning and regulating ecosystem services. Additionally, effective use of unutilized land (the area occupied by bunds) by planting multipurpose grasses and trees on the bunds may offset the yield lost due to a reduction in planting area. If high value grasses and trees can be grown on this land, farmers can harvest fodder for animals or fuel wood, both in scarce supply in Ethiopia. Growing of these grasses and trees can also help the stability of the bunds and reduce maintenance cost. Economic feasibility analysis also showed that, soil and water conservation practices became economically more viable if physical and agronomic soil and water conservation practices are integrated.

1. Agro-ecological Intensification of Farming Systems in the East and Central African Highlands Bernard Vanlauwe, Guy Blomme and Piet van Asten 2. Agricultural Intensification and the Food Security Challenge in Sub-Saharan Africa Brian A. Keating, Peter S. Carberry and John dixon 3. The Agro-ecological Solution?! Food Security and Poverty Reduction in Sub-Saharan Africa, with an Emphasis on the East African Highlands Henk Breman Theme 1: Systems Components 4. CIALCA Interventions for Productivity Increase of Cropping System Components in the African Great Lakes Zone Pieter Pypers et al. 5. Exploring the Scope of Fertilizer Use in the East African Region Lydia Wairegi and Piet van Asten 6. The 4R Nutrient Stewardship in the Context of Smallholder Agriculture in Africa Shamie Zingore and Adrian Johnston 7. Mitigating the Impact of Biotic Constraints to Build Resilient Banana Systems in Central and Eastern Africa Rony Swennen et al. 8. Challenges for the Improvement of Seed Systems for Vegetatively Propagated Crops in Eastern Africa Julian Smith, Daniel Coyne and Elmar Schulte-Geldermann Theme 2: System Integration 9. CIALCA's Efforts on Integrating Farming System Components and Exploring Related Trade-offs Piet van Asten et al. 10. Towards Ecologically Intensive Smallholder Farming Systems: Design, Scales and Trade-offs Evaluation Pablo Tittonell 11. Using the 'Livestock Ladder' as a Means for Poor Crop-livestock Farmers to Exit Poverty in Sud-Kivu Province, Eastern DR Congo Brigitte L. Maass et al. 12. N2Africa: Putting Nitrogen Fixation to Work for Smallholder Farmers in Africa Ken E. Giller et al. 13. Integrating Climate Change Adaptation and Mitigation in East African Coffee Ecosystems Henk van Rikxoort et al. Theme 3: Drivers for Adoption 14. Agricultural Technology Diffusion and Adoption in Banana and Legume Based Systems of Central Africa Emily Ouma et al. 15. Supply and Demand Drivers of the Sustainable Intensification of Farming Systems through Grain Legumes in Central, Eastern and Southern Africa Joseph Rusike et al. 16. Assessing and Improving the Nutritional Diversity of Cropping Systems Roseline Remans et al. 17. Disseminating Agroforestry Innovations in Cameroon: Are Relay Organizations Effective? Ann Degrande et al. 18. Participatory Re-introduction of Vicia Faba Beans in Resource-poor Farming Systems: Adoption of a Farmer-led Initiative Erik Karltun et al. Theme 4: Communicating and Disseminating Complex Knowledge 19. Walking the Impact Pathway: CIALCA's Efforts to Mobilize Agricultural Knowledge for the African Great Lakes Region Boudy van Schagen et al. 20. Scalability and Farmer Heterogeneity: Implications for Research on Sustainable Intensification John Lynam 21. Integrated Agricultural Research for Development (IAR4D): An Approach to Enhance the Livelihoods of Smallholder Farmers in the Lake Kivu Region Robin Buruchara et al. 22. Communication Channels Used in Dissemination of Soil Fertility Management Practices in the Central Highlands of Kenya Sarah W. Kimaru-Muchai et al. 23. Targeting Farmers' Priorities for Effective Agricultural Intensification in the Humid Highlands of Eastern Africa Jeremias Mowo et al. Index

To combat land degradation in the Central Rift Valley (CRV) of Ethiopia, farmers are of crucial importance. If farmers perceive land degradation as a problem, the chance that they invest in land management measures will be enhanced. This study presents farmers’ perceptions of land degradation and their investments in land management, and to what extent the latter are influenced by these perceptions. Water erosion and fertility depletion are taken as main indicators of land degradation, and the results show that farmers perceive an increase in both indicators over the last decade. They are aware of it and consider it as a problem. Nevertheless, farmers’ investments to control water erosion and soil fertility depletion are very limited in the CRV. Results also show that farmers’ awareness of both water erosion and soil fertility decline as a problem is not significantly associated with their investments in land management. Hence, even farmers who perceive land degradation on their fields and are concerned about its increase over the last decade do not significantly invest more in water erosion and soil fertility control measures than farmers who do not perceive these phenomena. Further research is needed to assess which other factors might influence farmers’ investments in land management, especially factors related to socioeconomic characteristics of farm households and plot characteristics which were not addressed by this study.

Land degradation, especially water erosion and nutrient depletion, seriously affects agricultural production in the Central Rift Valley of Ethiopia. Farmers' investments to conserve their land are until now however quite limited. The objective of this study is to identify the major factors that determine farmers' decisions how much and where to invest in land management. Exploratory factor analysis and Pearson correlation were used to analyse the data from 240 households operating 738 plots in three different production domains. The study identified five major factors that influence farmers' decisions how much to invest in land management: (1) households' resource endowments, (2) farming experience and knowledge, (3) access to information, (4) social capital and (5) availability of family labour. This result implies that extension strategies aiming at sustainable land management should try to enhance households' resources endowments and improve their access to information. Moreover, the influence of social capital and availability of family labour indicates the crucial importance of collective action in land management. Similarly, the study revealed that farmers are more willing to invest in plots that (1) are vulnerable to water erosion, (2) have better soil fertility and (3) are larger. However, the influence of these factors on farmers' investments in land management was highly variable across the considered production domains. Hence, the diversity in social, economic, cultural and biophysical conditions must be taken into account by rural extension programmes. This calls for site-specific land management strategies that can be planned and implemented at micro-level with active participation of farmers.

Farmers apply several and often different farmer-specific strategies to cope with and adapt to the perceived trend of declining rainfall and crop productivity. A better understanding of the factors affecting farmers’ coping and adaptation strategies to counteract both trends is crucial for policies and programs that aim at promoting successful rainfed agriculture in Ethiopia. The objective of this study was to identify the major factors that affect farmers’ coping and adaption strategies to rainfall variability and reduction in crop yield in the central Rift valley (CRV) of Ethiopia. A survey was conducted among 240 randomly selected farmers within six kebeles in the CRV using structured and pretested questionnaires. Multivariate probit (MVP) regression model was used to identify these key factors that affect farmers’ coping and adaptation strategies to the declining trends of rainfall and crop productivity. Generally, this study identified several factors that affect farmers’ choices of certain strategies, which can be grouped in four major factors: (1) livestock and landholdings, (2) availability of labour and knowledge, (3) access to information, and (4) social and cultural factors. Farmers with better resources, labour, knowledge, access to information and social capital had better coping and adaptation strategies to the declining rainfall and crop productivity. To conclude, improving farmers’ asset accumulation, access to information and knowledge are needed. Moreover, strengthening social capital and labour sharing institutions in the CRV is crucial to increase farmers’ capacities to cope with and adapt to environmental changes such as rainfall and crop yield variability.