Evans School Policy Analysis & Research Group (EPAR)

Common estimates of agricultural productivity rely upon crude measures of crop yield, typically defined as the weight harvested of a crop divided by the area harvested. But this common yield measure poorly reflects performance among farm systems combining multiple crops in one area (e.g., intercropping), and also ignores the possibility that farmers might lose crop area between planting and harvest (e.g., partial crop failure). Drawing on detailed plot-level data from the LSMS-ISA in Tanzania, Nigeria, and Ethiopia, we show how various yield measurement decisions affect estimates of smallholder yields for a variety of crops. We consider the effect of measuring production by plot area, area planted, and area harvested, of trimming the top 1% and 2% of values, and of considering different groups of farmers according to total area planted. 

This presentation summarizes the biotic (insects, viruses, fungi, bacteria, weeds, and post-harvest pests) and abiotic (drought and soil nutrients) stresses that may be addressed or countered in order to improve crop yield in Sub-Saharan Africa and South Asia. Data is sourced from FAOSTAT, GAEZ, a series of academic papers by Waddington & Dixon, and IMPACT model estimates. Slides compare area harvested, yield, and yield gap percentage with total calories per year, the 2005 value of production, and projected growth between 2005-2030. 

This report combines analyses from four previous EPAR briefs on the effects of climate change on maize, rice, wheat, sorghum, and millet production in Sub-Saharan Africa (SSA). In addition, this brief presents new analysis of the projected impact of climate changes in SSA. We include comparisons of the importance of each crop, of their vulnerability to climate change, and of the research and policy resources dedicated to each. Especially with respect to climatic susceptibility, these rankings provide a comparative summary based upon the analysis conducted in the four previous EPAR briefs, statistical analyses of historical yield and climate data, and future climate model predictions. According to the indicators analyzed, our research suggests that maize leads the cereal crops in terms of importance within SSA and in terms of research and policy attention. Our analysis of climate conditions and the crop’s physical requirements suggests that many maize-growing areas are likely to move outside the range of ideal temperature and precipitation conditions for maize production. Rice is the third most important crop in terms of consumption dependency, fourth in terms of production, but second only to maize in terms of research funding and FTEs. Sorghum and millet rank second and third in production importance and second and fifth in consumption importance, but rank below maize and rice in terms of FTE researchers. Their role is complicated by the fact that they are often considered inferior goods; SSA consumers often substitute away from sorghum and millet consumption if they are able to do so. Wheat is the least-produced crop of the five, and the second to last in terms of consumption importance. However, it still ranks above millet in terms of FTE researchers.

Ecological farming and conventional farming are two approaches to producing food. The term “ecological farming” describes a range of agricultural systems that seek to provide food and environmental and social benefits by using natural processes and local resources rather than off-farm, purchased inputs (commonly referred to as “external inputs”). Recent debate about the merits of ecological farming over conventional methods has centered on each system’s ability to increase production in the context of numerous and varied biophysical and social constraints. A review of the literature suggests that ecological farming can offer some benefits to smallholder farmers, but that specific approaches must be tailored to local climate and soil conditions and availability of labor, training, and organic inputs.