Evans School Policy Analysis & Research Group (EPAR)

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 report investigates the potential environmental and socio-economic benefits and costs of glyphosate resistant cassava.  Glyphosate resistant crops (also referred to as glyphosate tolerant) have been rapidly adopted by a number of crop producers because they simplify and/or reduce the cost of weed management. Glyphosate resistant crops also provide external environmental benefits by promoting reduced tillage agriculture, decreasing erosion and increasing soil health. However, glyphosate resistant crops also have some environmental costs, potentially leading to increased use of herbicides and environmental contamination. Because transgenic glyphosate resistant cassava is not currently in use, literature on its potential environmental and socioeconomic costs and benefits is limited. Therefore, this report draws on the literature for glyphosate resistant crops that are in current use, including maize, soybeans, sugar beets and canola (rapeseed). We find that socioeconomic and environmental impacts of glyphosate resistant crops differ by crop-type, agroecological conditions, production systems and local regulatory structure. Therefore, some benefits and costs associated with other glyphosate resistant crops may not be applicable to glyphosate resistant cassava. 

This brief presents a comparative analysis of men and women and of male- and female-headed households 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). We compare farm activity, productivity, input use, and sales as well as labor allocations by gender of the respondent and of the household head. In households designated “female-headed” a woman was the decision maker in the household, took part in the economy, control and welfare of the household, and was recognized by others in the household as the head. For questions regarding household labor (both non-farm and farm), the gender of the individual laborer is recorded, and we use this to illustrate the responsibilities of male and female household members. An appendix provides the details for our analyses.

This literature review examines the environmental impacts of water buffalo in pastoral and mixed farming systems in Sub-Saharan Africa, South Asia, and South America). The environmental impacts of water buffalo are less widely studied than those of the other livestock species included in this series; typically, the environmental impacts of water buffalo are incorporated into discussions of cattle without more detailed impacts being broken down by bovine type. In Asia and India, where the majority of buffalo are raised, buffalo are typically kept in small herds of only a few animals, which may minimize the local impacts of their grazing on vegetation, soil erosion and water pollution. Some aspects of buffalo feeding and life cycle patterns, as observed in the Amazon, may cause their greenhouse gas emissions to differ from those of cattle: buffalo can fatten on a wider range of grasses, reach market size in a shorter time, transition better from dry to wet seasons, and are more resistant to bovine diseases. While buffalo grazing and trampling can lead to land degradation, buffalo can contribute to nutrient and resource cycling in farming systems because their manure is considered good fertilizer and they can remove and utilize biomass grown on agricultural plots. Mitigation strategies vary by category of environmental impact, but largely suggest improved productivity to reduce land conversion, modified management systems (e.g., biodiversity, water use and consumption, farm and pastures, and waste), and the reduction of livestock numbers altogether.