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The purpose of this study was to explore how soil fertility management and farm nutrient balances varied across socio-economic groups in northern Ethiopia. Field surveys were carried out in 32 farms in Tigray, northern Ethiopia using different socio-economic groups, viz.: model/non model and female/male farmers. The nutrient input flows and output flows were monitored and analysed using Monitoring for Quality Improvement (MonQI) toolbox. Results of the study showed that average nitrogen (N), phosphorus (P) and potassium (K) balances in the highlands were − 30.8, 4.08 and − 42.75 kg ha−1, respectively while in the lowland the average nutrient balance were − 19.5, 2.09 and − 15.35 kg ha−1 for N, P and K, respectively. All farms had negative N and K nutrient balances, with lower negative N and K balance recorded in highlands than the lowlands. The reported values account about 0.6% and 2.7% of the total soil N and K pools in the highland and 0.3% and 0.8% in the lowland, respectively. Nutrient depletion rates in the highlands were 0.6% year−1 and 2.7% year−1 for N and K, respectively while for the lowlands the rates were 1.5% year−1 and 3.4% year−1 for N and K, respectively. Depletion rates were higher in the lowlands than highlands due to monocropping, crop residue removal and absence of soil water conservation. Most farms belonging to model farmers of both categories and non-model male farmers show more negative nutrient balance. We conclude that socio-economic status and being model farmers had less role in soil fertility maintenance. However, the more positive balance in female-headed households points to the need for adequate attention and support for the female-headed households. This study underscores the need for sustainable nutrient management. More so, agricultural policy should target female-headed households to help reduce the productivity gap between male-headed households and female-headed households.

This study identified decision variables influencing fertilizer adoption and optimal fertilizer rates among smallholder farmers in the Ethiopian highlands. The fertilizer adoption and fertilizer use were examined in four regional states using a questionnaire survey, which was administered to 2880 farm households. A double hurdle model was used to analyze factors influencing the two independent decisions of adoption of fertilizers and use of fertilizers. The model estimates of the first hurdle revealed that the probability of fertilizer adoption increased by 1.2% as household education status improved, by 1.4% for an increased number of active family members, by 5.6% with improved access to credit, by 3.4% with cooperative membership, by 3.3% with an increase in farm size, by 4.6% when soil and water conservation practices are employed, and by 3.4% when agroecology of the farm is located in the medium to highland zone. Conversely, the probability of fertilizer adoption reduced by 0.9% for an increase in family size, 0.6% with 1 km distance from all-weather road, 1.6% for a kilometer further to farm plots, and 0.9% for an increase in number of parcels. The intensity of use of fertilizers was influenced by education status of the household head, family size, access to credit, membership to cooperatives, use of crop rotation, annual income, number of farm plots owned, use of soil and water conservation, and agroecology. Therefore, a concerted effort is needed to encourage fertilizer adoption and optimum fertilizer use intensity by improving households’ resource endowment, institutional capacity to deliver services, and infrastructure development.

SI; International audience; Boosting the productivity of smallholder farming systems continues to be a major need in Africa. Challenges relating to how to improve irrigation are multi‐factor and multisectoral, and they involve a broad range of actors who must interact to reach decisions collectively. We provide a systematic reflection on findings from the research project EAU4Food, which adopted a transdisciplinary approach to irrigation for food security research in five case studies in Ethiopia, Mali, Mozambique, South Africa and Tunisia. The EAU4Food experiences emphasize that actual innovation at irrigated smallholder farm level remains limited without sufficient improvement of the enabling environment and taking note of the wider political economy environment. Most project partners felt at the end of the project that the transdisciplinary approach has indeed enriched the research process by providing different and multiple insights from actors outside the academic field. Local capacity to facilitate transdisciplinary research and engagement with practitioners was developed and could support the continuation and scaling up of the approach. Future projects may benefit from a longer time frame to allow for deeper exchange of lessons learned among different stakeholders and a dedicated effort to analyse possible improvements of the enabling environment from the beginning of the research process. © 2020 The Authors. Irrigation and Drainage published by John Wiley & Sons Ltd on behalf of International Commission for Irrigation and Drainage

Urban population growth is driving the expansion of urban and peri-urban agriculture (UPA) in developing countries. UPA is providing nutritious food to residents but the manures produced by UPA livestock farms and other wastes are not properly recycled. This paper explores the effects of four scenarios: (1) a reference scenario (business as usual), (2) increased urbanization, (3) UPA intensification, and (4) improved technology, on food-protein self-sufficiency, manure nitrogen (N) recycling and balances for four different zones in a small city (Jimma) in Ethiopia during the period 2015-2050. An N mass flow model with data from farm surveys, field experiments and literature was used. A field experiment was conducted and N use efficiency and N fertilizer replacement values differed among the five types of composts derived from urban livestock manures and kitchen wastes. The N use efficiency and N fertilizer replacement values were used in the N mass flow model. Livestock manures were the main organic wastes in urban areas, although only 20% to 40% of animal-sourced food consumed was produced in UPA, and only 14% to 19% of protein intake by residents was animal-based. Scenarios indicate that manure production in UPA will increase 3 to 10 times between 2015 and 2050, depending on urbanization and UPA intensification. Only 13% to 38% of manure N will be recycled in croplands. Farm-gate N balances of UPA livestock farms will increase to > 1 t-ha-1 in 2050. Doubling livestock productivity and feed protein conversion to animal-sourced food will roughly halve manure N production.Costs of waste recycling were high and indicate the need for government incentives. Results of these senarios are wake-up calls for all stakeholders and indicate alternative pathways.

Rapid urbanization in developing countries is attracting urban livestock farming, which is associated with feed nutrient imports and manure nutrient accumulations. Here, we report on manure nutrients (N, P and K) production on urban livestock farms in Addis Ababa and Jimma in Ethiopia, and estimate manure recovery on these farms and its recycling in urban, peri-urban and rural crop farms. Estimates were based on data from farm surveys, statistics, literature and model calculations. Urban livestock farms had on average 13 tropical livestock units and positive N, P and K balances. Urban crop farms had negative N and K balances, and did not use manure from urban livestock farms. We estimated that 0.5–2.6 Gg N, 0.2–0.8 Gg P and 0.9–3.7 Gg K can be collected in manure from the 5,200 urban livestock farms in Addis Ababa year−1, and can be recycled in crop land. Two manure allocation strategies were explored: balanced P fertilization and balanced N fertilization. The former allowed greater precision in matching nutrient supply to demand, and was associated with greater manure transport and distribution, up to rural areas. Manure recycling has several benefits: synthetic fertilizer savings (75–300 million Ethiopian Birr year−1 for Addis Ababa), soil fertility replenishment, and reductions in water pollution. However, there are various cultural, educational and institutional barriers for manure recycling. We argue that more quantitative data and scenario analyses are needed for deliberative decision making and for exploring more sustainable development pathways of urban livestock farms, re-connected to crop farms via manure recycling.

Urban and peri-urban agriculture (UPA) is important for food security in fast growing cities of developing countries. UPA also may have an important role in nutrient re-cycling at the interface of rural and urban areas. However, little is known about this role and whether it is different for different UPA systems. Here, we report on diversity and nutrient balances of UPA systems in three main cities of Ethiopia. Data collected from 425 households (Addis Ababa: 175, Adama: 126 Jimma: 124) were subjected to categorical principal component analysis and cluster analysis to classify the households. Four farm types per city and overall six: commercial livestock (cLS), commercial vegetable crop (cVC), subsistence field crop (sFC), cLScVC, cLScVCsFC and sVCsFC were identified across the three cities. Two types, cLS and cLScVC were common to the three cities. The farm types differed in resource endowment, income, soil fertility management and nutrient balances. cLS systems accumulated 450, 85 and 260 kg N, P and K ha−1 year−1 and had 26% N and P and 15% K use efficiency, respectively while sFC systems depleted − 30 kg N and − 17 kg K ha−1 year−1 and had 155% N and > 100% K use efficiency. There was little exchange of manure and crop residue between LS, FC and VC systems. To use the potential role of UPA in nutrient re-cycling, a directive that imposes LS systems to distribute their surplus manure resources to proximate FC and VC systems and improve their nutrient use efficiency should be put in place.

Improving the productive capacity of lands has been on the international development agenda for many years. Yet, to date insufficient progress has been made. Although there have been successes, they tend to be of limited impact, and spontaneous spreading of good practices is low. In this article, different intervention paradigms are reviewed. It is concluded that interventions differ in their fundamental view of drivers for change. We found interventions that aim to increase the total amount of nutrients within the soil, either through increasing inputs or through increasing demands, but seldom both at the same time. We also found interventions that aim to increase the efficacy of existing soil nutrients through either increasing the nutrient holding capacity (e.g. through mulching) or the release of nutrients (e.g. through liming). The differentiation of these approaches has strong effects on the institutional organization of the intervention. This article makes the case for integrating these different approaches and for more collaboration at institutional levels to facilitate this process.

Agriculture is considered as the backbone of Ethiopian economy. The government promotes rural development through policies that enhance intensive and commercially-oriented agriculture. Soil quality may be the bottleneck of these ambitions as more than half of the agricultural land shows signs of land degradation. Soil organic carbon (SOC) contents are a key aspect of soil quality, where relatively high SOC contents indicate better water holding capacity, nutrient retention capacity and better structure of the soil. In this research, SOC balances were used as indicator for short and midterm changes in SOC contents. SOC balances were calculated using data collected from 6914 fields for three years (2012-2014) using a simple input-out approach. On average, SOC balances were three tons per hectare per year. This equals 4 to 7% of the total soil organic carbon stock, which varied according to regions and cropping systems. SOC depletion rates were high in the mountainous and high cultivation intensity sites in central and northern Ethiopia where cereal based cropping systems dominates. Under the current practice, soils will eventually become exhausted and lose their productivity. This alarming trend could be reversed by integrating organic matter and nutrient management strategies and by providing alternative sources for feed and fuel supply of the community.

Mixed crop–livestock (MC–LS) farms are assumed to be more environmental friendly than specialized livestock systems, due to their better options for internal nutrient recycling. However, there are large differences among MC–LS farms in nutrient allocation and recycling. Here, we posit that the relative allocation of nitrogen to crop and livestock compartments, expressed as crop–livestock ratio (CLS), determines the performance of MC–LS farms. Among 300 urban and peri-urban farms studied in 2014, 42 MC–LS farms (Addis Ababa: 20; Jimma: 22) were re-interviewed in 2016, using MonQIt (monitoring tool) questionnaire. The performances of these farms were evaluated using partial nitrogen balance (PNB), N use efficiency (NUE), N recycling index and net farm income (NFI). CLS was negatively related to N input, PNB and NFI. Livestock oriented MC–LS farms had 4–5 times higher N input and 7 times higher PNB than crop oriented MC–LS farms, because they had 2–4 times higher NFI and purchased more external N input. This indicated that N allocation has significant environmental and economic implications. Sensitivity analyses suggested that NUE at farm system level can be improved by 20–25% and N recycling (NR) by 10–20% over the current condition. In conclusion, MC–LS farms are diverse, and much of the diversity can be captured by the CLS indicator. NUE and NR of peri-urban MC–LS farms in Ethiopia can be significantly improved through NUE enhancing measures: targeted exchange of crop residues and manure between crop and livestock activities within and between farms and improving animal NUE through breeding and precision feeding.

In the original publication, in Table 6, the asterisks (***) indicating the P values appeared under the column of use efficiency for N

This study has two objectives: 1) Look at several approaches that aim to increase or promote sustainable agriculture, and to identify similarities and differences, while deriving implications for policy makers. 2) Provide insight in how the approaches to sustainable agriculture contribute to these priorities.

Continuing soil degradation remains a serious threat to future food security. Yet, global soil degradation assessments are based on qualitative expert judgments or remotely sensed quantitative proxy values that suffice to raise awareness but are too coarse to identify appropriate sustainable land management interventions. Studies in China and Sub Saharan Africa illustrate the considerable impact of degradation on crop production but also point to the need for solutions dependent on location specific agro-ecological conditions and farming systems.The development of a comprehensive approach should be feasible to better assess both extent and impact of soil degradation interlinking various scales, based on production ecological approaches and remote sensing to allow disentangling natural and human induced causes of degradation. A shared common knowledge base cataloguing hard-won location-specific interventions is needed for successfully preventing or mitigating degradation.

The global demand for agricultural products, including food, is rapidly increasing due to population growth and shifts in consumption patterns. The required increase in agricultural production is predominantly to be achieved in countries with relatively low agricultural production levels at present. These are mainly developing countries and countries in transition, the so-called non-Annex I countries of the UNFCCC. However, intensification of agricultural production systems is currently closely linked to high emissions of greenhouse gases notably nitrous oxide (N2O) and methane (CH4). In this paper the relations between population growth, agricultural development and emissions of N2O and CH4 were assessed for 10 non-Annex I countries, viz. China, India, Vietnam, Brazil, Argentina, Mexico, Mongolia, Nigeria, Tanzania and South Africa. We combined FAO data on agricultural production levels, CENSUS data on population statistics and EDGAR data on N2O and CH4 emissions. The projected trends in agricultural production indicate that emissions of N2O and CH4 are expected to increase rapidly in the coming years and will level off from 2040 onwards. The results confirm the positive relation between population increase and increased emissions from agricultural activities for most countries. However, for some countries (South Africa, China and Mexico) this relation was weak or absent. Although numerous factors (e.g. changes in international trade) may have scattered the relation and we were unable to explain this decoupling, it suggests that population growth can be possible without additional emissions. The variation between the different countries and farming systems is however large and mitigation measures at farm-level should be tailored to the wide diversity in environmental conditions, regional customs and farming systems. (C) 2009 Elsevier Ltd. All rights reserved.

Re-use of nutrients within farming systems contributes to sustainable food production in nutrient limited production systems. Re-use is established when nutrients pass through several farm compartments before they leave the farm via marketable products. In this paper re-use of nitrogen is examined as an indicator for sustainable soil fertility management. Re-use (RU, kg farm−1) was defined as the amount of nitrogen that was translocated within one farm divided by the sum of transitions between farm compartments within a farm. In 2002, a total of 101 farms belonging to 4 farmer field schools in Kenya were analysed using the NUTMON (now known as MonQI) toolbox. The farms were distributed over 4 farmer field schools located in two agro-ecological zones. RU was positively related to the net farm income and to crop yields. However, data were scattered and often local farm conditions veiled the relation between nitrogen management strategies and farm performances. The results of this paper demonstrate that different agro-ecological zones with diverse production constraints have developed different in-farm nitrogen management strategies that are best adapted to the local conditions, but may have different environmental impacts.

The provision of farmers with proper and balanced fertilizer recommendations is becoming increasingly important, for reasons of crop productivity, food security, and sustainability. Phosphorus (P) response trials with wheat were conducted on Nitisols at 14 sites in the central Ethiopian highlands during the 2010 and 2011 cropping seasons. The treatments, comprising six levels of P fertilizer (0, 10, 20, 30, 40, and 50 kg P ha−1), were arranged in a randomized complete block design with three replicates. Based on a yield difference between the control and the P treatments, 90% of sites responded to P fertilizer. Application of P fertilizer increased wheat grain yield, up to 30% more than the control. Extractable soil P concentrations (Bray 2, 0–15 cm deep) 3 weeks after planting significantly responded to P fertilizer rate. The critical P concentration (for 90% relative yield) was 13.5 mg kg−1. Most sites tested had Bray 2 P values −1. In the absence of a soil test, a recommendation of 40 kg P ha−1, resulting in the best response overall, could be made for the first year of application. We also recommend that to prevent a potential loss of wheat yield, a maintenance application of at least 5–12 kg P ha−1 be applied every year, irrespective of the calculated recommended rate, in order to replace P exported from the field in produce. Further field trials are required to determine interactions between P response and the effects of climate, soil properties, and other management practices.

In this paper the suitability of a buffer strip to reduce nitrate concentrations in the upper groundwater was tested for a sandy arable soil in The Netherlands during two consecutive leaching seasons. The bufferstrip was a 3.5 m wide unfertilised grass strip adjacent to a ditch on an arable field. In total 24 groundwater wells were installed in 4 transects perpendicular to the ditch to determine Cl, NO3 and δ15N concentrations. Piezometers were installed to assess the groundwater flow, which was in the direction of the ditch with small downward leakage across a peat layer at about 3 m depth. Nitrogen was dominantly present as nitrate (NO3). The NO3-N concentrations under the bufferstrip were significantly lower than under the adjacent arable field. The lower concentrations were due to dilution, uptake by grass and denitrification. Nitrate was actively removed in the bufferstrip, since the Cl/NO3 ratios were higher in the bufferstrip than in the remainder of the field. Furthermore, δ15N data indicated that denitrification occurred in the groundwater and increased with decreasing distance to the ditch. NO3-N loads to the ditch were estimated at 8.5 kg ha−1yr−1, which is relatively low for this area. We can, however, not determine whether these relatively low NO3-N loads were causally related to the reduced NO3-N concentrations in the bufferstrip. Nevertheless, the results of the present study are promising and justify additional research on the efficiency of bufferstrips to reduce NO3 concentrations in shallow groundwater, and subsequently reduce NO3 loading of surface water, under Dutch conditions.