No abstract

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 recycling, 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.

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 socioeconomic 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.

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

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.