The impact of rainwater harvesting and fertilizer micro-dosing on farm and household sustainability in rural Tanzania

Food insecurity and poverty are of major concern for farmers in Tanzania, and the technologies rainwater harvesting coupled with fertilizer micro-dosing promise to aid in easing these burdens, particularly in a water-limited context. In this study, I performed an ex-post assessment of the impact of these two innovations in the sustainability of households and farms, in two contrasting regions of Tanzania semi-arid Dodoma and semi-humid Morogoro, to see if they would be relevant to promote in the country. The method used accounts for households’ and farms’ characteristics, estimates sustainability indicators, and uses a difference-in-differences propensity score matching (PSM) estimator. The results indicate contrary to expectations, that the households in the semi-arid region of Dodoma are not benefiting from the adoption of the innovations, neither in food security nor in economic sustainability and even exacerbated the frequency of water conflicts by 7%. On the opposite, in the semi-humid region of Morogoro, these two innovations enhanced households’ environmental sustainability and food security by increasing these indices by 3% and 10% respectively. Using aggregated indicators to assess the impact of rainwater harvesting and fertilizer micro-dosing on economic, social and environmental aspects, was relevant to show that these technologies have limited benefits on the sustainability of farmers’ households in Tanzania, thus need to be complemented by policies that promote households’ characteristics associated with better food security and economic results, such as training for higher levels of education, greater land security, and promoting the cultivation of cash-crops.