Types of Research
- (-) Remove 2008 filter 2008
- (-) Remove Sub-Saharan Africa filter Sub-Saharan Africa
- (-) Remove Agricultural Productivity, Yield, & Constraints filter Agricultural Productivity, Yield, & Constraints
- (-) Remove 2015 filter 2015
This brief reviews the evidence of realized yield gains by smallholder farmers attributable to the use of high-quality seed and/or improved seed varieties. Our analysis suggests that in most cases, use of improved varieties and/or quality seed is associated with modest yield increases. In the sample of 395 trials reviewed, positive yield changes accompanied the use of improved variety or quality seed, on average, in 10 out of 12 crops, with rice and cassava as the two exceptions.
Cassava production is prone to many constraints throughout the production cycle, including biotic, abiotic, and management constraints. This brief reviews the literature on the production impacts of two key cassava stressors: cassava bacterial blight (CBB) and postharvest physiological deterioration (PPD). We summarize available estimates of the frequency and magnitude of these constraints relative to other drivers of cassava production losses that affect smallholder farmers in Sub-Saharan Africa (SSA), review the control strategies proposed in the literature, report on the views of several experts in the field, and identify research gaps where relatively little appears to be known about CBB or PPD yield impacts or best practices for CBB or PPD management.
As our understanding of the impacts of hidden hunger on human nutrition grows, understanding the link between fertilizer use and human nutrition becomes increasingly important. This report presents an analysis of both grey and peer-reviewed literature on the effects of fertilizer use on nutritional quality of food, particularly the staples of maize, rice, wheat, cassava and legumes. We find that some nutrient deficiencies, such as zinc, can be effectively addressed through fertilizer use while others, such as iron deficiency, are more difficult to address. Promising breakthroughs with fortified and complete fertilizers present the opportunity to correct multiple deficiencies. Current fertilizer products exist that, when applied with the proper agronomic methods, can have a significant effect on nutrition in the developing world. However, it is important to recognize that there are many factors in the developing world that have the potential to inhibit the benefits of fertilizer for human nutrition. Two significant factors are poor farmers’ difficulty in procuring the correct product and the relative sophistication required to apply fertilizers at the correct amounts and time to achieve desired results. In addition, researchers have not focused on fertilizer and nutrition studies until recently, particularly micronutrient fertilizer studies, and few studies specifically study the impacts of fertilizer on human nutrition. More research needs to be done to understand the most effective combinations and techniques, and to understand whether these methods truly increase the amount of nutrients bioavailable to humans.