Peeing out of poverty? Human fertilizer and the productivity of farming households.

In many parts of the world, soils poor in nutrients are farmed with little addition of fertilizer, further depleting the farmland. The very same farmers often face poor sanitary solutions. So-called ecological sanitation aims at providing sanitation and at recycling nutrients as fertilizer. This human fertilizer may act as a substitute for artificial fertilizers (improving the household budget) or as a complement (improving soil quality, increasing agricultural yields). We collected demographic, economic and farming data from 618 households in southern Mali, of which 155 benefitted from an ecological sanitation investment program. We do not find any support for human fertilizer being used complementary, although the effect on yields varies over crops. Instead, we find that beneficiary households substitute artificial fertilizer with human fertilizer at 10 to 15 per cent of the average household use of artificial fertilizers. While our results imply small economic incentives at the household level for investing in ecological sanitation, we do not account for health effects at the household or community level.