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Ethiopia is one of the countries most vulnerable to the impacts of climate variability and change on agriculture. The present study aims to understand and characterize agro-climatic variability and changes and associated risks with respect to implications for rainfed crop production in the Central Rift Valley (CRV). Temporal variability and extreme values of selected rainfall and temperature indices were analysed and trends were evaluated using Sen's slope estimator and Mann–Kendall trend test methods. Projected future changes in rainfall and temperature for the 2080s relative to the 1971–90 baseline period were determined based on four General Circulation Models (GCMs) and two emission scenarios (SRES, A2 and B1). The analysis for current climate showed that in the short rainy season (March–May), total mean rainfall varies spatially from 178 to 358 mm with a coefficient of variation (CV) of 32–50%. In the main (long) rainy season (June–September), total mean rainfall ranges between 420 and 680 mm with a CV of 15–40%. During the period 1977–2007, total rainfall decreased but not significantly. Also, there was a decrease in the number of rainy days associated with an increase (statistically not significant) in the intensity per rainfall event for the main rainy season, which can have implications for soil and nutrient losses through erosion and run-off. The reduced number of rainy days increased the length of intermediate dry spells by 0·8 days per decade, leading to crop moisture stress during the growing season. There was also a large inter-annual variability in the length of growing season, ranging from 76 to 239 days. The mean annual temperature exhibited a significant warming trend of 0·12–0·54 °C per decade. Projections from GCMs suggest that future annual rainfall will change by +10 to −40% by 2080. Rainfall will increase during November–December (outside the growing season), but will decline during the growing seasons. Also, the length of the growing season is expected to be reduced by 12–35%. The annual mean temperature is expected to increase in the range of 1·4–4·1 °C by 2080. The past and future climate trends, especially in terms of rainfall and its variability, pose major risks to rainfed agriculture. Specific adaptation strategies are needed for the CRV to cope with the risks, sustain farming and improve food security. [ABSTRACT FROM PUBLISHER]

Global climate change is predicted to shift seasonal temperature and precipitation patterns. An increasing frequency of extreme weather events such as heat waves and prolonged droughts is predicted, but there are high levels of uncertainty about the nature of local changes. Crop adaptation will be important in reducing potential damage to agriculture. Crop diversity may enhance resilience to climate variability and changes that are difficult to predict. Therefore, there has to be sufficient diversity within the set of available cultivars in response to weather parameters critical for yield formation. To determine the scale of such ‘weather response diversity’ within barley (Hordeum vulgare L.), an important crop in northern conditions, the yield responses of a wide range of modern and historical varieties were analysed according to a well-defined set of critical agro-meteorological variables. The Finnish long-term dataset of MTT Official Variety Trials was used together with historical weather records of the Finnish Meteorological Institute. The foci of the analysis were firstly to describe the general response of barley to different weather conditions and secondly to reveal the diversity among varieties in the sensitivity to each weather variable. It was established that barley yields were frequently reduced by drought or excessive rain early in the season, by high temperatures at around heading, and by accelerated temperature sum accumulation rates during periods 2 weeks before heading and between heading and yellow ripeness. Low temperatures early in the season increased yields, but frost during the first 4 weeks after sowing had no effect. After canopy establishment, higher precipitation on average resulted in higher yields. In a cultivar-specific analysis, it was found that there were differences in responses to all but three of the studied climatic variables: waterlogging and drought early in the season and temperature sum accumulation rate before heading. The results suggest that low temperatures early in the season, delayed sowing, rain 3–7 weeks after sowing, a temperature change 3–4 weeks after sowing, a high temperature sum accumulation rate from heading to yellow ripeness and high temperatures (⩾25°C) at around heading could mostly be addressed by exploiting the traits found in the range of varieties included in the present study. However, new technology and novel genetic material are needed to enable crops to withstand periods of excessive rain or drought early in the season and to enhance performance under increased temperature sum accumulation rates prior to heading. [ABSTRACT FROM PUBLISHER]

Lack of nitrogen limits food production in poor countries while excessive nitrogen use in industrial countries has led to transgression of the planetary boundary. However, the potential of spatial redistribution of nitrogen input for food security when returning to the safe boundary has not been quantified in a robust manner. Using an emulator of a global gridded crop model ensemble, we found that redistribution of current nitrogen input to major cereals among countries can double production in the most food-insecure countries, while increasing global production of these crops by 12% with no notable regional loss or reducing the nitrogen input to the current production by one-third. Redistribution of the input within the boundary increased production by 6-8% compared to the current relative distribution, increasing production in the food-insecure countries by two-thirds. Our findings provide georeferenced guidelines for redistributing nitrogen use to enhance food security while safeguarding the planet., (© The Author(s) 2024. Published by Oxford University Press on behalf of National Academy of Sciences.)

Agroforestry has the potential to sequester carbon (C) and nitrogen (N), thereby counteracting climate change and soil degradation. However, the lack of empirical quantitative evidence on determinants of C and N stocks hampers the management of these stocks. The aim of this study was to identify the key determinants of the C and N stocks in multistrata agroforestry. We sampled 81 plots with broad variation in 12 hypothetical determinants of C and N stocks aboveground and in two soil layers, located in three Ethiopian regions with varied multistrata agroforestry traditions and characteristics. Above-ground stocks were assessed using an allometric equation, and soil stocks were assessed with the fixed-depth method. The hypothetical determinants, i.e., the duration of agroforestry practice, the tree density, the proportion of plants with a high basal diameter, legumes and native species, the species diversity, the main crops, soil texture and pH, and altitude, were tested using linear mixed models. The duration of agroforestry, tree density, and proportion of plants with a high basal diameter (>25 cm) explained half of the variation in the soil C stock, which represented nearly three quarters or more of the total C stock. Duration and tree density explained most of the soil N stock, although legumes also influenced soil N. A high proportion of large legume trees reduced C/N, whereas a high proportion of large non-legume trees increased C/N. The aboveground C stock was explained by species diversity or the proportion of stems with a basal diameter >10 cm, depending on the main crop. There is a high potential to manage C and N stocks and their persistence, as well as soil productivity, by managing the duration of agroforestry, the density of large trees, the proportion of legumes, and the main crops in multistrata agroforestry., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

The industrial world has converted inert soil and atmospheric nutrients into reactive fertilizer flows that endanger water quality, biodiversity and climate. Simultaneously, poor nations starve because of the shortage of these nutrients in agricultural soils. Here we propose a redistribution of accumulated nutrients to enhance food security while counteracting the current degradation of critical Earth system processes. Residue and sediment nutrients could be processed and transported to food-insecure regions through the opposite logistics used to ship rock phosphate across the globe. Financing through trading accumulated rights could trigger the required innovations in processing, logistics and thinking. Such a socially just 'one Earth currency' could leverage a transformation towards resilience, equity and dignity across the critical Earth system processes., (© 2021. Springer Nature Limited.)

Beekeeping provides honey, protein-containing drone broods and pollen, and yield-increasing pollination services. This study tested the hypothesis that beekeeping can result in net-positive impacts, if pollination services and protein-containing by-products are utilised. As a case example, Finnish beekeeping practices were used. The study was performed using two different approaches. In both approaches, the evaluated impacts were related to climate change, land use, and freshwater use, and were scaled down to represent one beehive. The first approach considered honey production with pollination services and the replacement of alternative products with co-products. The impacts were normalised to correspond with planetary boundary criteria. The second approach evaluated the impacts of the different products and services of beekeeping separately. In the first approach the honey production system moved towards a safe operational space. Freshwater use was the impact category with the largest shift towards a safe operational space (39% shift). The second approach caused a global warming potential of honey production of 0.65 kg CO2-eq kg -1 , when pollen and drone broods were considered as by-products and the influence of pollination services were not included. When honey, pollen, and drone broods were considered as co-products and pollination services were included, the impacts regarding land use and climate change were net-positive. The impact of freshwater use was relatively small. For honey, the impacts on the climate change, land use, and freshwater use were -0.33 kg CO2-eq kg -1 , -7.89 m 2  kg -1 , and 14.01 kg kg -1 , respectively. The impact allocation with co-products and pollination services was conclusive. A lack of consideration for the impact reduction of pollination led to beekeeping having a negative impact on the environment. Based on these results, beekeeping enhances food security within planetary boundaries, provided that pollination services and protein-containing by-/co-products are utilised., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)

The rapid conversion of native forests to farmland in Ethiopia, the cradle of biodiversity, threatens the diversity of the arbuscular mycorrhizal fungi (AMF) pivotal to plant nutrition and carbon sequestration. This study aimed to investigate the impact of this land-use change on the AMF species composition and diversity in southern Ethiopia. Soil samples were collected from nine plots in each of three land-use types: native forest, agroforestry, and khat monocropping. The plots of the three land-use types were located adjacent to each other for each of the nine replicates. Three 10 × 10m subplots per plot were sampled. AMF spores were extracted from the soil samples, spore densities were determined, and species composition and diversity were evaluated through morphological analysis. Both spore density and species richness were statistically significantly higher in the native forest than in the agroforestry plots with no clear difference to khat, whereas the true diversity (exponential of Shannon-Wiener diversity index) did not differ among the three land-use types due to high evenness among the species in agroforestry. In total, 37 AMF morphotypes belonging to 12 genera in Glomeromycota were found, dominated by members of the genera Acaulospora and Glomus. The highest isolation frequency index (78%) was recorded for Acaulospora koskei from native forest. Consequently, the agroforestry system did not appear to aid in preserving the AMF species richness of native forests relative to perennial monocropping, such as khat cultivation. In contrast, the native forest areas can serve as in situ genetic reserves of mycorrhizal symbionts adapted to the local vegetative, edaphic, and microbial conditions.

In this time of the pandemic, nothing is as it used to be. This change creates space for new narratives towards resilience. The resilience perspective implies preparing for shocks as well as various futures that might evolve. Thus, more sustainable food systems cannot only be built to be pandemic proof. This preparation can be facilitated by co-designing contrasting future narratives, identifying means for developing capacity to adapt to those futures and developing tools to enhance that capacity, such as demonstrated here. The capacity of food systems to adapt and transform is enhanced by dialogue, transparency and collective learning in food value chains and networks, sovereignty over resources, and built-in diversity in response to change. In market-led global food chains, supplier-buyer diversity is important, while in public-led regions with some market protection, farm and crop diversity might matter more in response to variability in weather, price and policies. During, for example, an international conflict, or the time of a pandemic, diverse food sourcing from local producer-consumer cooperatives to community-supported and urban agriculture could secure food for citizens. Assessments of critical diversity in response to shocks and volatility can help actors to tailor effective diversity to manage resilience while avoiding the long-feared trade-off between diversity and resource-use efficiency. The interdependence of humanity deserves attention, as food systems are only as resilient as their weakest actor. A truly resilient global food system implies not only preparedness for coming shocks and changes but also a foundation that makes shocks less probable and critical., Competing Interests: Conflict of interestThe authors declared that they have no conflict of interest., (© The Author(s) 2020.)

Food security relies on the resilience of staple food crops to climatic variability and extremes, but the climate resilience of European wheat is unknown. A diversity of responses to disturbance is considered a key determinant of resilience. The capacity of a sole crop genotype to perform well under climatic variability is limited; therefore, a set of cultivars with diverse responses to weather conditions critical to crop yield is required. Here, we show a decline in the response diversity of wheat in farmers' fields in most European countries after 2002-2009 based on 101,000 cultivar yield observations. Similar responses to weather were identified in cultivar trials among central European countries and southern European countries. A response diversity hotspot appeared in the trials in Slovakia, while response diversity "deserts" were identified in Czechia and Germany and for durum wheat in southern Europe. Positive responses to abundant precipitation were lacking. This assessment suggests that current breeding programs and cultivar selection practices do not sufficiently prepare for climatic uncertainty and variability. Consequently, the demand for climate resilience of staple food crops such as wheat must be better articulated. Assessments and communication of response diversity enable collective learning across supply chains. Increased awareness could foster governance of resilience through research and breeding programs, incentives, and regulation., Competing Interests: The authors declare no conflict of interest., (Copyright © 2019 the Author(s). Published by PNAS.)

Soil carbon (C) represents the largest terrestrial carbon stock and is key for soil productivity. Major fractions of soil C consist of organic C, carbonates and black C. The turnover rate of black C is lower than that of organic C, and black C abundance decreases the vulnerablility of soil C stock to decomposition under climate change. The aim of this study was to determine the distribution of soil C in different pools and impact of agricultural management on the abundance of different species. Soil C fractions were quantified in the topsoils (0-15cm) of 23 sites in the tropical highlands of Ethiopia. The sites in central Ethiopia represented paired plots of agroforestry and adjacent control plots where cereal crops were traditionally grown in clayey soils. In the sandy loam and loam soils of northern Ethiopia, the pairs represented restrained grazing with adjacent control plots with free grazing, and terracing with cereal-based cropping with adjacent control plots without terracing. Soil C contained in carbonates, organic matter and black C along with total C was determined. The total C median was 1.5% (range 0.3-3.6%). The median proportion of organic C was 85% (range 53-94%), 6% (0-41%) for carbonate C and 6% (4-21%) for black C. An increase was observed in the organic C and black C fractions attributable to agroforestry and restrained grazing. The very low concentration of the relatively stable black C fraction and the dominance of organic C in these Ethiopian soils suggest vulnerability to degradation and the necessity for cultivation practices maintaining the C stock., (Copyright © 2018 Elsevier B.V. All rights reserved.)

More than half of the cultivation-induced carbon loss from agricultural soils could be restored through improved management. To incentivise carbon sequestration, the potential of improved practices needs to be verified. To date, there is sparse empirical evidence of carbon sequestration through improved practices in East-Africa. Here, we show that agroforestry and restrained grazing had a greater stock of soil carbon than their bordering pair-matched controls, but the difference was less obvious with terracing. The controls were treeless cultivated fields for agroforestry, on slopes not terraced for terracing, and permanent pasture for restrained grazing, representing traditionally managed agricultural practices dominant in the case regions. The gain by the improved management depended on the carbon stocks in the control plots. Agroforestry for 6-20 years led to 11.4 Mg ha -1 and restrained grazing for 6-17 years to 9.6 Mg ha -1 greater median soil carbon stock compared with the traditional management. The empirical estimates are higher than previous process-model-based estimates and indicate that Ethiopian agriculture has greater potential to sequester carbon in soil than previously estimated., (© 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.)

Efficiency in the use of resources stream-lined for expected conditions could lead to reduced system diversity and consequently endanger resilience. We tested the hypothesis of a trade-off between farm resource-use efficiency and land-use diversity. We applied stochastic frontier production models to assess the dependence of resource-use-efficiency on land-use diversity as illustrated by the Shannon-Weaver index. Total revenue in relation to use of capital, land and labour on the farms in Southern Finland with a size exceeding 30 ha was studied. The data were extracted from the Finnish Profitability Bookkeeping data. Our results indicate that there is either no trade-off or a negligible trade-off of no economic importance. The small dependence of resource-use efficiency on land-use diversity can be positive as well as negative. We conclude that diversification as a strategy to enhance farm resilience does not necessarily constrain resource-use efficiency., Competing Interests: The authors have declared that no competing interests exist.