Catálogo de publicaciones - libros

Over the last decade, international concerns about climate change have stimulated broad investment in the pursuit of agriculture that is more climate-smart. These concerns are particularly pressing in Africa, where most farmers remain severely impoverished and dependent on rain-fed production systems. This volume collates some of the latest research from agricultural scientists working to speed up the development and adoption of more climate-smart farming systems in eastern and southern Africa. These 25 papers highlight ongoing efforts to better characterise climate risks, develop and disseminate climate-smart varieties and farm management practices, and integrate these technologies into well-functioning value chains. The papers emphasise the additional research efforts needed to improve the understanding and response to climate risk. The expert authors also make suggestions for strengthening the responsiveness of agricultural research and extension systems to future climate changes.

This paper offers an overview of how climate change is already affecting farmers across eastern and southern Africa, and how it will continue to affect them in the future. The rising temperatures and increased rainfall variability associated with climate change are undermining the livelihoods and food security of Africa’s farmers, most of whom work at a subsistence level and also face problems of poverty, inadequate infrastructure and poor governance. To address these problems, governments and development organizations have promoted climate-smart agriculture (CSA). These projects, however, have been constrained by inadequate data and predictions regarding future climate change. In particular, farmers in Africa need better projections of the climate hazards for specific regions. Historical weather data at the local level contains many gaps, and the continuing collection of such data could be much improved. Strengthening the database of observed weather is critical to understanding the changes that have occurred already, to project future changes, and to plan appropriately to address them. Once collected and analyzed, climate data must be communicated in ways that help decision-makers understand climate impacts. Good tools are available—such as ClimateWizard.org and Servir ClimateServ—but practitioners at the local level must have the access and training to use them. Even in places where projections are uncertain, steps can be taken now to implement CSA practices and make farmers more resilient in the face of climate change.

Climate change influences the occurrence and transmission of a wide range of livestock diseases through multiple pathways. Diseases caused by pathogens that spent part of their life cycle outside the host (e.g. in vectors or the environment) are more sensitive in this regard, compared to those caused by obligate pathogens. In this chapter, we use two well-studied vector-borne diseases—Rift Valley fever (RVF) and tick-borne diseases (TBDs)—as case studies to describe direct pathways through which climate change influences infectious disease-risk in East and southern Africa. The first case study demonstrates that changes in the distribution and frequency of above-normal precipitation increases the frequency of RVF epidemics. The second case study suggests that an increase in temperature would cause shifts in the spatial distribution of TBDs, with cooler and wetter areas expected to experience heightened risk with climate change. These diseases already cause severe losses in agricultural productivity, food security and socio-economic development wherever they occur, and an increase in their incidence or geographical coverage would intensify these losses. We further illustrate some of the control measures that can be used to manage these diseases and recommend that more research should be done to better understand the impacts of climate change on livestock diseases as well as on the effectiveness of the available intervention measures.

In developing and least developed countries (LDCs) such as Angola, where household income and the food security of rural communities is heavily dependent on rain-fed subsistence agriculture, there is a risk that climate change will undermine the potential contributions of the agriculture sector toward national objectives for sustainable development and food security. Furthermore, climate change is likely to alter the spatial variation in crop suitability, thus shifting the dynamics of food production at the district, provincial, national and regional levels. Decision-makers have at their disposal very little agronomic and climate information downscaled and interpreted for the local level, and this poses obstacles to the creation of long-term strategies for climate-resilient agricultural development. To provide this type of information, this study assessed the projected spatial changes in suitability of Angola’s region for production of two staple crops (maize and cassava), in response to future temperature and precipitation changes projected by 29 general circulation models (GCMs). The projected changes to crop suitability indices were calculated for six provinces using the Food and Agriculture Organization’s (FAO’s) EcoCrop analytical tool, and were analysed both in terms of changes in absolute crop suitability as well as changes in spatial distribution of crop-suitable areas. Those changes were aggregated to the province level to support improved integration of information on future suitability of staple crops in each of the six studied provinces. The increased availability and quality of information will support improved decision-making on specific crops, cultivars and farming practices to be promoted as part of a strategy for climate-resilient agricultural and socio-economic development in Angola.

Although climate change is likely to affect a wide variety of sectors in Zimbabwe, the risk to agriculture stands out most since agriculture is the mainstay of the country’s economy. In addition, there is little information available on how to help smallholder farming systems and livelihoods respond to these risks. To determine the effects on crop production of expected changes in precipitation patterns and projected increases in carbon dioxide (CO) and temperature, we used two process-based crop models—the Decision Support System for Agrotechnology Transfer (DSSAT) model and the Agricultural Production Systems Simulator (APSIM) model. The models were calibrated and validated to assess the effects of single and combined climatic factors on grain and stover yield performance of maize and groundnut, across three soil types. The two models generally agree on the effects that different climatic factors have on both maize and groundnuts, however, the magnitude of the effects varied. For example, reductions on maize grain yields are more pronounced in the APSIM model while the DSSAT model shows more pronounced reduction of maize stover yields. Both models show yield benefits under elevated CO concentration for groundnuts negating the effects of increased temperatures when evaluating the combined effects of the climatic factors. However, yield increases for both groundnut grain and stover are more pronounced in the DSSAT model. The key finding is that soils play an important role in determining outputs of crop-climate interactions: they can buffer or aggravate climatic impacts.

To address climate change (CC) in eastern and southern Africa (ESA) will require accelerated development and dissemination of crop varieties with climate-smart (CS) traits over the coming decades. However, investment in crop improvement and rates of variety turnover are currently extremely low in the region. Smallholder farmers, who generate the bulk of agricultural output in ESA, continue to cultivate old crop varieties that lack CS traits such as drought tolerance and resistance to new and emerging pests and diseases. The emergence of the private seed sector in ESA provides a unique opportunity to complement established public crop improvement programmes, and accelerate development and dissemination of CS crop varieties through scalable, certified seed systems. This chapter will discuss; the growth of the private seed sector since the seed industry in ESA was deregulated, the importance of public-private partnerships in driving genetic gains for CS traits, and the importance of developing a favourable regional regulatory environment that incentivises the private sector to rapidly scale out CS crop varieties (and withdraw obsolete varieties).

Climate change projections suggest increased frequency of drought in many parts of sub-Saharan Africa (SSA). The replacement of old varieties of maize with new drought-tolerant (DT) varieties will be crucial to respond to the future risk of drought, as it already is today. The first group of locally developed maize hybrids in Ethiopia—BH140, BH660 and BH540—were commercialised between 1988 and 1995, but were not selected for drought tolerance. Among these, BH660 remained the most popular and widely grown maize variety in the Ethiopian maize belt between 2000 and 2010, accounting for nearly 50% of maize area under improved seed. A new DT hybrid, BH661, with better agronomic performances under optimum and random drought than BH660, was identified and released in 2011. In 2016, 9000 tonnes of certified seed—enough to plant 360,000 ha—was produced and marketed. The concerted effort of breeders and seed producers as well as governmental and non-governmental extension workers drove the development, release and rapid adoption of BH661 contributing to food and income security of more than 300,000 households by mitigating the effects of climate change in Ethiopia. The success of BH661 is a valuable and timely case study for breeders, seed companies, extension agents, regulatory bodies and policy-makers striving to develop and disseminate new DT varieties in sub-Saharan Africa.

Changing climates in eastern and southern Africa will require farmers to adjust which crop varieties they grow in order to adapt to changing patterns of weather, pests and diseases. Delivering more suitable, climate-smart crop varieties requires well-functioning seed systems in which actors work in harmony across the supply chain. Although a great deal of previous development funding has been used to breed new varieties and to encourage farmers to adopt them, the availability of early-generation seed (EGS) continues to be limited by bottlenecks in the supply chain. These problems are particularly significant for non-hybrid varieties and less-commercialized food crops developed by public-sector institutions. This study uses two contrasting case studies from Kenya to illustrate the importance of making improved bean seed varieties available to farmers. The first case study documents a successful instance of EGS transfer, whereas the second highlights the types of barriers that can prevent successful variety adoption. Improved coordination among system actors is necessary to reduce the barriers surrounding EGS provision and production, and thereby strengthen climate-adaptive and adaptable seed systems.

Root, tuber and banana (RTB) crops are key to food security, nutrition and income for approximately 300 million poor people in the humid tropics of sub-Saharan Africa (SSA). Climate change and limited access to quality seed due to underdeveloped seed systems pose challenges which could unravel the benefits of RTB crops. Here, we present measures taken to address these challenges based on two case studies in Kenya and Mozambique. The Mozambique case study analyses the introduction of drought-resistant orange-fleshed sweetpotato varieties to address household food security and nutrition insecurity while strengthening resilience to climatic shocks. The study in Kenya focusses on the development of seed systems to address the chronic shortage of quality potato seed, which has led to over 50% yield loss. Given the need for strict quality control to manage the high risk of seed degeneration in vegetatively propagated crops, developing seed systems that deliver climate-smart varieties requires a multi-disciplinary approach to ensure that the scientific, technical, socio-economic and gender aspects are considered to ensure sustainability of interventions.

Supporting the diversification of African agricultural systems by the further integration of nutritious, perennial ‘new and orphan crops’ (NOC) is seen as an important means to address malnutrition in Africa. The approach may be of particular relevance in the context of climate change, with the diversification of food systems possibly supporting more resilient food provision in the face of more variable weather patterns. Here, we relate how perennial NOC can support dietary diversity at a subnational level within a seasonal context based on crop portfolios. We also explore the resilience of the production of perennial crops, based on year-on-year crop yield data for eastern and southern African countries provided by the Food and Agriculture Organization Corporate Statistical Database (FAOSTAT). These analyses support the role of perennial NOC in creating resilient food systems and indicate a potential for compensatory annual–perennial crop combinations, although further research is needed on this point. Making use of FAOSTAT country-level trend data, we also relate constraints and potential opportunities for perennial food crop production. We then explain how NOC are currently being promoted in the region, with specific reference to the work of the African Orphan Crops Consortium and its breeder-training programme. We discuss the challenges faced in delivering perennial NOC planting material to farmers, which are exacerbated by climate change, and the measures that are being taken to overhaul delivery systems.