Evans School Policy Analysis & Research Group (EPAR)

This literature review examines the environmental impacts of cattle in pastoral and mixed farming systems in Sub-Saharan Africa and South Asia. Cattle are frequently cited as having the most severe overall environmental impacts among livestock species due to: methane and nitrous oxide released from digestion and manure; land use and conversion; desertification; inefficient ratio of weight of feed and water consumed to weight of meat and dairy produced; conflicts between livestock herders and wildlife; the large volume of wastewater produced in meat and hide processing; and overgrazing of riparian areas. However, cattle have also been found to provide several environmental benefits such as keeping wildlife corridors open, preventing the spread of noxious weeds, and promoting the growth of local vegetative species. 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, grain and other feed, and waste), and the reduction of livestock numbers altogether. 

This literature review examines the environmental impacts of chickens in pastoral and mixed farming systems in Sub-Saharan Africa and South Asia. Compared to ruminant species (cattle, water buffalo, and goats), chickens produce lower carbon dioxide, methane, and nitrous oxide emissions, are a less significant driver of human expansion into natural habitat or of overgrazing, have lower impacts on the water cycle, and cause less destruction of natural habitats. Poultry’s major impacts on land degradation result from the production of their grain-intensive feed. Chicken production also poses a threat to avian biodiversity, as chickens are susceptible to viruses and act as vectors of disease transmission to avian wildlife. Chicken manure is widely viewed as a valuable fertilizer in developing countries, although transportation costs limit manure sales in local markets and the high nitrogen-phosphorous ratio can impact certain soils and water. Mitigation strategies vary by category of environmental impact, but largely suggest modified management systems (e.g., biodiversity, health, livestock feed efficiency, and waste).

The Government of Kenya (GoK) has historically encouraged its farmers to use fertilizer by financing infrastructure and supporting fertilizer markets.  From 1974 to 1984, the GoK provided a fertilizer importation monopoly to one firm, the Kenya Farmers Association.  However, the GoK saw that this monopoly impeded fertilizer market development by prohibiting competing firms from entering the market and, in the latter half of the 1980s, encouraged other firms to enter the highly regulated fertilizer market. This report examines the state of fertilizer use in Kenya by reviewing and summarizing literature on recent fertilizer price increases, Kenya’s fertilizer usage trends and approaches, market forces, and the impact of government and non-government programs. We find that most studies of Kenya’s fertilizer market find it to be well functioning and generally competitive, and conclude that market reform has stimulated fertilizer use mainly by improving farmers’ access to the input through the expansion of private retail networks. Overall fertilizer consumption in Kenya has increased steadily since 1980, and fertilizer use among smallholders is among the highest in Sub-Saharan Africa. Yet fertilizer consumption is still limited, especially on cereal crops, and in areas where agroecological conditions create greater risks and lower returns to fertilizer use.