Scaling up the impact of rainwater harvesting techniques on small-scale farming in Niger

Abdul Latif Jameel Poverty Action Lab (J-PAL) affiliate researchers Jenny Aker and Kelsey Jack evaluated the challenges of adopting rainwater harvesting techniques on semi-arid small-scale farm regions in Niger. The study was led by the Agricultural Technology Adoption Initiative (ATAI), co-led by J-PAL and the Center for Effective Global Action at University of California, Berkeley (CEGA), and in partnership with Niger's Ministry of Environment.

The study took place in the Sahel region of Sub-Saharan Africa, where nearly 80% of farmland is degraded. Researchers tested the barriers to utilising a rainwater harvesting technique known as demi-lunes, which captures rainwater over a period of two to three days while mitigating soil runoff and improving nutrient availability in the soil. In Niger's Zinder region, small-scale farmers to not make use of the practice, which can improve crop yields. The study sought to determine whether the cost of implementing the technology (around USD 80 per hectare) or lack of technical information prevented the use of demi-lunes. Researchers conducted a randomised evaluation which included a half-day, in-person technical training for the theory and practice of demi-lune construction and application. The study also provided conditional and unconditional cash transfers for the construction of the systems.

The study found that in villages that received the training course, use of demi-lunes increased by 90 percentage points compared to the villages that did not receive the intervention. Meanwhile, the supplementation of either conditional or unconditional cash transfers had limited additional impact on the farmers' use of the technique. The promising results from the evaluation have helped researchers garner funds from J-PAL's King Climate Action Initiative (K-CAI) and USAID-DIV for further evaluation of training content and format and monitoring methods across a larger group of farmers in the Maradi and Zinder regions of eastern Niger. The scale-up will involve introducing an additional rainwater harvesting technique known as zai, testing the impact of remote sensing as a monitoring method as opposed to in-person monitoring, and expanding the training to all agricultural households in the studied villages. The scale-up will cover 400 villages, impacting nearly 6,000 households.