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More than 200 million people living in dryland regions of Sub-Saharan Africa make their living from agriculture. Most are exposed to weather shocks, especially drought, that can decimate their incomes, destroy their assets, and plunge them into a poverty trap from which it is diffi cult to emerge. Their lack of resilience in the face of these shocks can be attributed in large part to the poor performance of agriculture on which their livelihood depends. Opportunities exist to improve the fortunes of farming households in the drylands. Improved farming technologies that can increase and stabilize the production of millet, sorghum, maize, and other leading staples are available. Irrigation is technically and economically feasible in some areas and offers additional opportunities to increase and stabilize crop production, especially small-scale irrigation, which tends to be more affordable and easier to manage. Yet many of these opportunities have not been exploited on a large scale, for reasons that include lack of farmer knowledge, nonavailability of inputs, unfavorable price incentives, high levels of production risk, and high cost. Future production growth in drylands agriculture is expected to come mainly from raising yields and increasing the number of crop rotations on land that is already being cultivated (intensifi cation), rather than from bringing new land into cultivation (extensifi cation). Controlling for rainfall, average yields in rainfed cropping systems in Sub-Saharan Africa are still much lower than yields in rainfed cropping systems in other regions, suggesting that there is considerable scope to intensify production in these systems. Furthermore, unlike in other regions, production of low-value cereals under irrigation is generally not economic in Sub-Saharan Africa unless the cereals can be grown in rotation with one or more high-value cash crops. The long-run strategy for drylands agriculture, therefore, must be to promote production of staples in rainfed systems and production of high-value cereals (for example, rice), horticultural cops, and industrial crops in irrigated systems. Based on a detailed review of currently available technologies, Improved Crop Productivity for Africa’s Drylands argues that improving the productivity and stability of agriculture in the drylands has the potential to make a signifi cant contribution to reducing vulnerability and increasing resilience. At the same time, it is important to keep in mind that in an environment characterized by limited agro-climatic potential and subject to repeated shocks, farming on small land holdings may not generate suffi cient income to bring people out of poverty.

Africa’s lands are largely vulnerable and threatened by soil degradation and low water availability, especially in semi-arid and arid regions, limiting crop and livestock productivity and farmer livelihood options. Therefore, in African agricultural lands, adopting/improving measures that conserve soil and water resources is crucial. This review aims to provide an update on soil and water conservation (SWC) in terms of farmer practices and research actions and explore how SWC technologies and practices represent a pathway to build or re-establish soil health and enhance sustainable agriculture in Africa. It also aims to increase knowledge on best-fit SWC approaches. Soil conservation, which includes measures of controlling soil erosion and maintaining or improving soil fertility, is inseparable from water conservation. On agricultural lands, the two are typically co-addressed. Increasing plant biomass production through improved water, crop and soil management practices, and managing this biomass judiciously, have direct and indirect impacts on conserving soils and water resources, particularly in drylands. This study focuses on rainfed agricultural systems. We discuss the barriers and challenges to scaling up best-bet SWC technological and management options. Moreover, we show that options, such as Conservation Agriculture (CA), Agroforestry (AF), as well as integrated soil fertility management (ISFM) and field-scale rainwater harvesting (RWH), remain promising for the preservation and improvement of soil health in Africa’s farmlands and improving the resilience of agrosystems to climate change and variability as well as droughts.

Improving soil water holding capacity (WHC) through conservation agriculture (CA)-practices, i.e., minimum mechanical soil disturbance, crop diversification, and soil mulch cover/crop residue retention, could buffer soil resilience against climate change. CA-practices could increase soil organic carbon (SOC) and alter pore size distribution (PSD); thus, they could improve soil WHC. This paper aims to review to what extent CA-practices can influence soil WHC and water-availability through SOC build-up and the change of the PSD. In general, the sequestered SOC due to the adoption of CA does not translate into a significant increase in soil WHC, because the increase in SOC is limited to the top 5–10 cm, which limits the capacity of SOC to increase the WHC of the whole soil profile. The effect of CA-practices on PSD had a slight effect on soil WHC, because long-term adoption of CA-practices increases macro- and bio-porosity at the expense of the water-holding pores. However, a positive effect of CA-practices on water-saving and availability has been widely reported. Researchers attributed this positive effect to the increase in water infiltration and reduction in evaporation from the soil surface (due to mulching crop residue). In conclusion, the benefits of CA in the SOC and soil WHC requires considering the whole soil profile, not only the top soil layer. The positive effect of CA on water-saving is attributed to increasing water infiltration and reducing evaporation from the soil surface. CA-practices’ effects are more evident in arid and semi-arid regions; therefore, arable-lands in Sub-Sahara Africa, Australia, and South-Asia are expected to benefit more. This review enhances our understanding of the role of SOC and its quantitative effect in increasing water availability and soil resilience to climate change.

This review aims to emphasize the important role that goats and dairy goats play for many small-scale rural families worldwide, as well as to introduce a proposal for categorizing the main dairy goat production systems (DGPSs), using a multifactorial approach but emphasizing rainfall and nutritional supplementation level, as the focal categorization factors. The main DGPSs were divided into two metasystems based on available resources, each consisting of three production subsystems. In the first metasystem, the three subsystems have limited water, biotic, and economic resources, whose main economic rationality is based on reducing risk rather than maximizing outputs. In contrast, the three subsystems of the second metasystem usually have increased biotic, economic, and water resources, whose main emphasis involves maximizing product yield rather than reducing risk. The first metasystem involves DGPSs with a very limited or null nutritional supplementation: (a) subsistence, (b) extensive, and (c) agro-silvopastoral. The second metasystem includes those DGPSs with different levels of nutritional supplementation: (d) semi-extensive, (e) semi-intensive, and (f) intensive. There are numerous significant global initiatives focused on scientific collaboration and sharing information regarding nutrition, reproductive, and genetic technologies related to the safety and nutraceutical quality of goat milk and products while contextualized in different DGPSs. Hence, such scenarios should create additional opportunities for researchers, producers, policymakers, and development workers to come together and align interests and needs and exchange knowledge on effective goat farmer support strategies, environmental management, and consumer education. Undoubtedly, it is essential to reevaluate the DGPSs in the world since millions of producers and their families—most of them poor and marginalized—need this species, society needs their products, most of the worldwide arid and semi-arid lands need their recovery, and all of us should encourage the fulfillment of the sustainable development goals.

Long-term cropping system experiments are one of the most reliable sources of information for informing sustainable agriculture and predicting future trends. When combined with crop modelling, expansion of findings on optimised management approaches is possible. In this study, results from a South African semi-arid region long-term (66 years) maize (Zea mays L.) trial are presented and combined with crop modelling to identify the impacts of fertilisation and residue management on yield and soil organic matter (SOM) levels. Simulated and observed results generally agreed well in calibration and testing exercises with APSIM. For the fertilised treatment, residue retention led to a 41% increase in average yield over the long term, and for unfertilised treatment the average yield increase was even higher at 59%. The greatest SOM decline of 46% was observed for the unfertilised plus residue removal treatment (over 66 years and considering a 60 cm soil depth). Fertilising and retaining residue reduced the SOM decline to 18%. Using only fertiliser without residue retention did not lead to a declining yield trend over the long-term for this soil. The study indicated that the APSIM model can be used to explore the ecological intensification of maize production in sub-Saharan Africa. Further attention is recommended, however, on testing the simulation of subsoil SOM dynamics. The results of this study give insight into soil fertility in low-input maize production systems and quantify the benefits of N fertiliser and residue retention guided by long-term measured data.

We present maize production in sub‐Saharan Africa as a case study in the exploration of how uncertainties in global climate change, as reflected in projections from a range of climate model ensembles, influence climate impact assessments for agriculture. The crop model AquaCrop‐OS (Food and Agriculture Organization of the United Nations) was modified to run on a 2° × 2° grid and coupled to 122 climate model projections from multi‐model ensembles for three emission scenarios (Coupled Model Intercomparison Project Phase 3 [CMIP3] SRES A1B and CMIP5 Representative Concentration Pathway [RCP] scenarios 4.5 and 8.5) as well as two “within‐model” ensembles (NCAR CCSM3 and ECHAM5/MPI‐OM) designed to capture internal variability (i.e., uncertainty due to chaos in the climate system). In spite of high uncertainty, most notably in the high‐producing semi‐arid zones, we observed robust regional and sub‐regional trends across all ensembles. In agreement with previous work, we project widespread yield losses in the Sahel region and Southern Africa, resilience in Central Africa, and sub‐regional increases in East Africa and at the southern tip of the continent. Spatial patterns of yield losses corresponded with spatial patterns of aridity increases, which were explicitly evaluated. Internal variability was a major source of uncertainty in both within‐model and between‐model ensembles and explained the majority of the spatial distribution of uncertainty in yield projections. Projected climate change impacts on maize production in different regions and nations ranged from near‐zero or positive (upper quartile estimates) to substantially negative (lower quartile estimates), highlighting a need for risk management strategies that are adaptive and robust to uncertainty. Key Points We estimate the influence of global climate model uncertainty on projected maize yield changes in sub‐Saharan Africa due to climate change Five different GCM ensembles all project yield losses in the Sahel region and Southern Africa and sub‐regional increases in East Africa Irreducible internal variability is a major cause of uncertainty in crop model projections even out to 2090

Addressing the challenge of food and nutrition insecurity in Sub‐Saharan Africa (SSA) will require innovative agriculture production systems that support multiple objectives. In recent years, several high‐yielding, and nutrient‐dense varieties of cowpea ( Vigna unguiculata (L.) Walp), pearl millet ( Pennisetum glaucum (L.) R. Br.), and sorghum ( Sorghum bicolor (L.) Moench) have been developed purposely as dual‐purpose (DP) varieties in SSA to meet human nutrition and livestock feed needs. This review synthesized published data on DP varieties from cowpea, pearl millet, and sorghum. Findings showed that DP crops and varieties were largely grown by smallholder farmers in a variety of soil and climatic conditions with production systems characterized by large gaps between attainable and actual crop yields which varied significantly among regions. While the grain and fodder yield of traditional varieties (TV) of cowpea averaged 700 kg ha −1 and 860 kg ha −1 , respectively, the reported grain yield of DP varieties was 1100 kg ha −1 and 2150 kg ha −1 for fodder. The average grain yield of TV millet varieties was 750 kg ha −1 and 2500 kg ha −1 for fodder. Similarly, average grain yield for DP millet varieties was 2000 kg ha −1 and 4200 kg ha −1 fodder. Dual‐purpose sorghum varieties yielded greater grain (>3000 kg ha −1 ) and fodder (3500 kg ha −1 ) compared to TV. Little data were obtained on the nutritive qualities of cowpea, millet, and sorghum DP varieties. However, DP millet varieties were reported to be more digestible than TV varieties. Furthermore, adoption of DP varieties improves fertilizer use efficiency, profitability, environmental sustainability, and resilience of the whole farm system compared to TV. Considering fertilizer's high prices, availability, and quality in semi‐arid countries in addition to farmer poverty level, economic evaluation and environmental impact assessment are critical before wide dissemination.

Sorghum (Sorghum bicolor (L.) Moench) is the main food staple for millions of people in Sub-Saharan Africa (SSA) and Asia. Sorghum is relatively drought tolerant and cultivated in arid and semi-arid regions under rain-fed production. However, severe drought stress often leads to crop loss and declined productivity. The development and deployment of high-yielding and drought-adapted genotypes is a cost-effective strategy for sustainable sorghum production globally. The objective of this study was to determine drought tolerance and genotype-by-environment interaction (GEI) effects on grain yields of a population of African sorghum genotypes to identify high-yielding and drought-adapted genotypes for direct production and also for use in breeding programs. Two hundred and twenty-five sorghum genotypes were evaluated under non-stressed (NS), pre-anthesis drought stress (PreADS), and post-anthesis drought stress (PoADS) conditions under field and greenhouse environments using a 15 × 15 alpha lattice design in two replicates. The three water regimes and two environments resulted in six testing environments. Data were collected on grain yield and drought tolerance parameters, and additive main effect and multiplicative interaction (AMMI) analysis were computed. The mean grain yield under NS, PreADS, and PoADS were 3.70, 1.76, and 2.58 t/ha, in that order. The best genotypes adapted to non-stressed environments were G09, and G109, whereas G114 and G56 were suitable for non-stressed and stressed conditions. G72 and G75 displayed the best performance in PreADS conditions only, whereas genotypes G210 and G12 were identified as high performers under PoADS only. The AMMI analysis revealed that genotype (G), environment (E), and GEI were significant (p < 0.05), which accounted for 38.7, 44.6, and 16.6% of the total explained variation in grain yield. AMMI 4 was the best-fitting model for grain yield. Based on AMMI 4 and the Best Linear Unbiased Estimates (BLUPs) calculations, genotypes G119 and G127 with a grain yield of 5.6 t/ha and 6.3 t/ha were selected as being suitable for non-stressed conditions. Genotypes G8 and G71 with BLUPs of 2.5 t/ha and 2.6 t/ha were best-suited for pre-anthesis drought stress conditions, whereas genotypes G115 and G120 with BLUPs of 4.2 t/ha and 4.3 t/ha are recommended for post-anthesis drought-prone environments, respectively. The identified sorghum genotypes are recommended for production in dry agro-ecologies of sub-Saharan Africa characterized by pre-and-post anthesis drought stress. In addition, the identified genotypes are valuable genetic resources to develop novel drought-tolerance material.