Evans School Policy Analysis & Research Group (EPAR)

The purpose of this literature review is to examine research and decision-making tools that model the impacts of agricultural interventions. We begin with a short explanation of what model features are being described. We then review decision-support tools and user-end modeling tools (menu-driven tools with an interface designed for easy use), as well as academic and professional research models for assessing the potential impacts of agricultural interventions. This review also includes decision tools and models for analyzing agricultural and environmental policies outside of technology impacts in Sub-Saharan Africa and South Asia. The other tools mentioned here, for example a tool that considers nutritional intervention impacts, are included to help provide a broader understanding of the structure and availability of user-end, decision-making tools. In the final section of this brief, we review the most complex models used more in academic research than for in-field decision-making.

Ecosystem services are the benefits people obtain from ecosystems, such as provisioning of fresh water, food, feed, fiber, biodiversity, energy, and nutrient cycling. Agricultural production can substantially affect the functioning of ecosystems, both positively and negatively. The purpose of this report is to provide an overview of the impacts of agricultural technologies and practices on ecosystem services such as soil fertility, water, biodiversity, air, and climate. The report describes the environmental impacts of different aspects of intensive cropping practices and of inputs associated with intensification. We further explore these impacts by examining intensive rice systems and industrial crop processing. Although this report focuses on the impacts of agricultural practices on the environment, many of the practices also have implications for plant, animal, and human health. Farmers and others who come in contact with air, water, and soils polluted by chemical fertilizers and pesticides may face negative health consequences, for instance. By impacting components of the ecosystem, these practices affect the health of plants and animals living within the ecosystem. We find that the unintended environmental consequences of intensive agricultural practices and inputs are varied and potentially severe. In some cases, sustaining or increasing agricultural productivity depends upon reducing impacts to the environment, such as maintaining productive soils by avoiding salinization from irrigation water. However, in other cases, eliminating negative environmental impacts may involve unacceptable trade-offs with food provision or other development goals. Determining the appropriate balance of costs and benefits from intensive agricultural practices is a location-specific exercise requiring knowledge of natural, economic, and social conditions. 

Over the past several decades, donors, multilateral organizations and governments have invested substantial resources in developing and disseminating improved varieties of sorghum and millet in Sub-Saharan Africa (SSA). Researchers believe that sorghum and millet have the ability to improve food security and mitigate the influence of climate change on food production for some of the most vulnerable populations. As a result, agricultural scientists have focused on developing improved cultivars to increase the relative benefits of these two crops and disseminate this technology to a larger number of farmers. This report provides an overview of the development and dissemination of improved sorghum and millet cultivars, factors that influence the adoption of improved cultivars among farmers in SSA, and examples of interventions designed to encourage adoption in SSA. We find that while national governments and international research institutes have successfully developed a number of improved sorghum and millet cultivars, adoption rates in SSA (particularly in West and Central Africa) are low. The literature suggests that overall efforts have increased adoption rates, but at varying costs.

Though not indigenous to Sub-Saharan Africa (SSA), cassava plays, to varying degrees, five major roles in African development: famine-reserve crop, rural food staple, cash crop for urban consumption, livestock feed, and industrial raw material. Cassava production in SSA was historically a significant staple crop for smallholder farmers and continues to be the second most important food crop in Africa (after maize) in terms of calories consumed. Subsistence crops such as cassava are often considered women’s crops with the standard explanation that women are responsible for feeding the family and thus prefer to grow crops for the household. This brief reviews the role that women play in cassava production, and considers ways to better address gender issues from planting through post-harvest production. We find that the potential gains to cassava production made possible through improved technology will not be fully realized without the participation of women farmers and without women farmers having access to credit, markets, and extension services. Additionally, evidence from SSA suggests that labor for harvesting and processing, rather than labor for weeding, has become the key labor constraint for cassava, and addressing this concern may be more important than further yield increases for raising production levels.