Types of Research
In this brief we analyze patterns of intercropping and differences between intercropped and monocropped plots among smallholder farmers in Tanzania using data from the 2008/2009 wave of the Tanzania National Panel Survey (TZNPS), part of the Living Standards Measurement Study – Integrated Surveys on Agriculture (LSMS-ISA). Intercropping is a planting strategy in which farmers cultivate at least two crops simultaneously on the same plot of land. In this brief we define intercropped plots as those for which respondents answered “yes” to the question “Was cultivation intercropped?” We define “intercropping households” as those households that intercropped at least one plot at any point during the year in comparison to households that did not intercrop any plots. The analysis reveals few significant, consistent productivity benefits to intercropping as currently practiced. Intercropped plots are not systematically more productive (in terms of value produced) than monocropped plots. The most commonly cited reason for intercropping was to provide a substitute crop in the case of crop failure. This suggests that food and income security are primary concerns for smallholder farmers in Tanzania. A separate appendix includes the details for our analyses.
Local crop diversity and crop cultivation patterns among smallholder farmers have implications for two important elements of the design of agricultural interventions in developing countries. First, crop cultivation patterns may aid in targeting by helping to identify geographic areas where improved seed and other productivity enhancing technologies will be most easily applicable. Second, these patterns may help to identify potential unintended consequences of crop interventions focused on a single crop (e.g. maize). This report analyzes the distribution of crop diversity and crop cultivation patterns, and factors that can lead to changes in these patterns among smallholder farmers in Tanzania with a focus on regional patterns of crop cultivation and changes in these patterns over time, the factors that affect crop diversity and changes in crop diversity, and the level of substitutability between crops grown by smallholder farmers. All analysis is based on the Tanzania National Panel Survey (TNPS) datasets from 2008 and 2010. The paper is structured as follows. Section I provides a description of regional patterns of crop cultivation and crop diversity between the two years of the panel. Section II presents background on the theoretical factors affecting crop choice, and presents our findings on the results of a multivariate analysis on the factors contributing to crop diversity. Finally, Section 3 provides a preliminary analysis of the level of substitutability between cereal crop of importance in Tanzania (maize, rice and sorghum/millet) and also between these cereal crops and non-cereal crops.
Whiteflies are vectors for viral diseases such as cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), which can reduce yields substantially. The flies can also cause direct damage, more common on disease-resistant cassava varieties than on local cultivars, by feeding on the crop and causing root yield reductions. In this report we provide background on whitefly damage to cassava as well as evidence on the effectiveness of four control strategies: breeding for host plant resistance, intercropping and other planting strategies, insecticides and Insecticide Resistance Management (IRM), and biological control through parasitoids, fungus, and predators. Though we group information by strategy, most researchers report that controlling whiteflies and the viruses for which it is a vector requires a multifaceted approach.
Rice is the most important food crop of the developing world and is grown on over 155 million ha worldwide. Food security of the poor, especially in Asia, depends critically on rice availability at an affordable price. In this brief we examine the environmental constraints to, and impacts of, smallholder rice production systems in South Asia (SA) and Sub-Saharan Africa (SSA), noting where the analysis applies to only one of these regions. We highlight crop-environment interactions at three stages of the rice value chain: pre-production (e.g., land clearing), production (e.g., water and other input use), and post-production (e.g., waste disposal). At each stage we emphasize environmental constraints on production (e.g., poor soil quality, water scarcity, crop pests) and also environmental impacts of crop production (e.g., soil erosion, water depletion, pest resistance). We then highlight best or good practices for minimizing negative environmental impacts in smallholder rice production systems. Evidence on environmental issues in smallholder rice production is uneven. Far more research is available for Asian rice production systems, as compared to African rice systems. And with the possible exception of the evidence on water limits to increasing productivity, conclusions on the strength of published findings on crop-environment interactions in rice depends on one’s weighting of economic versus ecological perspectives, physical science versus social science, academic versus grey literature, and quantity versus quality of methods and findings.
This paper is the third in EPAR’s series on Higher Education in Africa. Our research tasks in this phase build on Phase I, in which we sought to identify measurable rates of return on tertiary agricultural education in Africa and describe the current state of African higher agricultural education (HAE), and Phase II, in which we identified countries’ experiences with national higher education capacity building through partnership building, cross-border opportunities such as ‘twinning,’ and various retention and diaspora engagement strategies. In this phase we discuss successful regional education models, particularly in Sub-Saharan Africa. We have organized our findings and analysis into three sections.The first section organizes the literature under categories of regional higher education models or ‘hubs’ and discusses measurement of the regional impact of higher education. The second section provides bibliometric data identifying academically productive countries and universities in Sub-Saharan Africa.The final section provides a list of regional higher education models identified in the literature and through a web-based review of existing higher education networks and hubs. We also include a list of challenges and responses to regional coordination.
This literature review examines the environmental constraints to, and impacts of, wheat production systems in South Asia (SA) and Sub-Saharan Africa (SSA). The review highlights crop-environment interactions at three stages of the wheat value chain: pre-production (e.g., land availability), production (e.g., heat, water, and soil), and post-production (e.g. storage, crop residues, and transport). At each stage we emphasize environmental constraints on production (e.g., poor soil quality, water scarcity, crop pests, etc.) and also environmental impacts of crop production (e.g., soil degradation, water depletion and pollution, greenhouse gas emissions, etc.). We then highlight published best practices for overcoming environmental constraints and minimizing environmental impacts in wheat production systems. We find that wheat is a significant crop that will need to increase production to meet increasing demand. Most land suitable for wheat production is already under cultivation. Improved production methods are needed to address the demand and avert environmental impacts of producing wheat. It should not be assumed that improved varieties alone will be able to realistically address growing demands for wheat. Improved variety seeds should be combined with best practices of improved crop management techniques: optimal planting time, zero tillage, fertilizer management, intercropping, crop residue incorporation, and improved storage techniques.
This brief present our analysis of sorghum and millet cultivation in Tanzania using data from the 2008/2009 wave of the Tanzania National Panel Survey (TZNPS), part of the Living Standards Measurement Study – Integrated Surveys on Agriculture (LSMS-ISA). In the 2007-2008 long and short rainy seasons, 13% of Tanzanian farming households cultivated sorghum and 6% cultivated millet, making these crops some of the least frequently cultivated priority crops in Tanzania. As a result, detailed analysis and determining statistical significance was limited by the low number of observations, particularly of millet. While sorghum and millet are often grouped together, our results suggest that in Tanzania there were differences among the households that cultivated these distinct crops. A separate appendix includes additional detail on our analyses.
Consumer attitudes are a key component in private sector market segmentation. Knowledge about consumers’ tastes can lead to better product design and more effective communication with target markets. Similarly, evidence suggests that farmers’ attitudes influence whether they adopt productivity-increasing technologies. Using consumer insights from the private sector, agricultural intervention programs can use market research, product development, and communication strategies to better understand farmers as consumers and best target interventions. This brief provides an overview of how farmers' attitudes affect their willingness to adopt new technology, and how knowledge of farmer attitudes can improve program design and implementation.
This report provides a genderal overview of the sweet potato value chain in Ethiopia. The first section describes trends in sweet potato production and consumption since the early 1990s. The second section describes the uses and importance of sweet potatoes in Ethiopia. The final section discuss major issues in production, post-production, and marketing. The literature available on sweet potetoes in Ethiopia was quite limited and draws on the wider literature on sweet potatoes in East Africa where needed. We find that Ethiopia ranks fifteenth in the world in terms of sweet potato production. Production has been rising quickly since 2008, following a period of slow decline in the early 2000s. Yields have also been rising slowly since 2008, but are below their peak from 2001. Sweet potato roots are consumed domestically, mostly by poor rural households. The vines also provide an important source of feed for livestock during the dry season. Major constraints to sweet potato production in Ethiopia include a lack of quality planting materials, pests and disease, and underdeveloped markets.
Uganda is the biggest sweet potato producer in Africa in terms of area harvested and production, although Burundi, Rwanda and Madagascar have significantly higher yields. Sweet potato is a major crop in Uganda, ranking third in cultivated area following plantains and cassava. Sweet potato ranks fourth in gross agricultural production value. The Government of Uganda has recognized sweet potatoes as an important crop for the country and a research priority, especially through establishing the National Agricultural Research Organization potato center. This report provides a general overview of the sweet potato value chain in Uganda. The first section describes trends in sweet potato production and consumption since 1996. The second section describes the varieties grown and their uses. The final section summarizes current practices and constraints in production, processing, and marketing.