Soil Fertility and Poverty in Developing Countries

In poor, semi-subsistence agricultural settings, soil fertility is a critical input to agricultural production and therefore to human welfare. The importance of soil health is magnified in such settings because poor farming families use fewer agricultural inputs than do farmers in wealthy countries; they also face higher levels of risk and have fewer financial tools to smooth away the impact of a bad year. For instance, while almost 100% of U.S. farmland devoted to corn receives inorganic fertilizer (USDA, 2018), only about a third of sub-Saharan African farmers appear to apply inorganic fertilizer, and those that apply nutrients do so at much lower levels than do American farmers (Sheahan and Barrett, 2017). Input rates tend to be higher in South Asia than in sub-Saharan Africa, but risk is still high; only 4% of Indian households are covered by crop insurance (Rajeev et al., 2016) versus 86% in the United States (Isabel, 2018). The implications of crop failure are so dire that unexpectedly high temperatures drive suicides in rural India (Carleton, 2017). African farmers are similarly at the mercy of rainfall and temperature patterns; less than 2% of farms are irrigated in most African countries (Sheahan and Barrett, 2017). Malagasy farmers in Madagascar are vulnerable to recursive pests and diseases due to the insufficient resources for risk-coping (Harvey et al., 2014).