Availability of organic nutrient sources and their effects on yield and nutrient recovery of tef [Eragrostis tef (Zucc.) Trotter] and on soil properties

Inadequate nutrient and organic‐matter supply constitutes the principal cause for declining soil fertility and productivity in much of sub‐Saharan Africa (SSA). In a survey in Gare Arera, the central Ethiopian highland, farmyard manure (FYM) and compost enriched with ash were identified as underutilized organic nutrient sources. Mustard meal, a by‐product of mustard‐seed oil production, is also locally available. On‐farm experiments were carried out on two major soil types (Nitisol and Vertisol) to study effects of the organic fertilizers, synthetic fertilizer (urea + triple superphosphate) and an unfertilized control on the yield and yield components of tef Eragrostis tef (Zucc) Trotter] and selected soil properties. Application of organic fertilizers at an N rate equivalent to that of urea produced grain yields of 82% and 99% of that produced with urea on Nitisol and Vertisol, respectively. The apparent N recovery from urea, mustard meal, FYM, and compost was, respectively, 31%, 25%, 16%, and 28% on Nitisol and 23%, 17%, 26%, and 21% on Vertisol. The mean agronomic efficiency for the organic and synthetic fertilizers on Nitisol was 20 and 24 kg grain (kg N)^–1 applied, respectively, whereas on the Vertisol, it was 13 kg grain (kg N)^–1 for both. On Vertisol, tef was most responsive to FYM and on Nitisol, it was most responsive to compost. Soil N and P contents increased due to organic‐fertilizer application. The results showed that compost enriched with ash is a good choice on Nitisol while FYM works well on Vertisol. Mustard meal can be applied on both soils.