Misperceived Quality: Fertilizer in Tanzania

Fertilizer use remains below recommended rates in most of Sub-Saharan Africa, contributing to poor crop yields and poverty. Farmers voice suspicion that available fertilizer is often adulterated, but these concerns are not backed by reliable evidence. In fact, an insight from industry but absent from academic literature is that profitable fertilizer adulteration is difficult. We surveyed all fertilizer sellers in Morogoro Region, Tanzania and tested 633 samples of their fertilizer. We also conducted a willingness-to-pay assessment with farmers. We find that fertilizers meet nutrient standards but that belief of rampant product adulteration persists among farmers. We find evidence of a quality inference problem in the market: 25% of fertilizer has deteriorated in observable ways and farmers rely on these observable attributes to (incorrectly) assess unobservable nutrient quality. We show that this misperception likely reduces technology adoption beyond the effect of nutrient quality being unobservable.