Sowing and irrigation strategies for improving rainfed tef (Eragrostis tef (Zucc.) Trotter) production in the water scarce Tigray region, Ethiopia

• Water stress late in season is most limiting factor for tef production in Tigray.
• Combined water and fertility stress on tef production is well simulated by AquaCrop.
• Early sowing is effective field management strategy to improve tef productivity.
• One-time irrigation application combats water stress late in season of rainfed tef.

Field experiments conducted under rainfed agriculture for three consecutive years (2008–2010) revealed that water stress at the late season is the most limiting factor for the productivity of tef (Eragrostis tef (Zucc.) Trotter) in Tigray, Ethiopia. Early sowing and one irrigation application late in the growing season, were evaluated with the AquaCrop model as management strategies to improve productivity. Simulations were run for three dominant soil types, under different soil fertility levels, and for four different locations in the region each with 19 years of historical climatic data. Advancing the sowing date, two to three weeks earlier than the commonly practiced by the farmers, resulted in stable yields and reduced the risks on yield failure by 72 to 100%. Moderate to high yields could only be achieved when the recommended fertilizer dose was applied. The yields became moderate but remained stable, by applying only 50% of the recommended dose, which is an affordable soil fertility management practice for the farmers. Considering the limited capacity of most farmers for irrigation, a very limited irrigation with only rainwater harvested during the growing cycle, was assessed as a strategy to further boost the productivity of tef in the region. Depending on the soil fertility level, one irrigation application of only 45 mm around flowering, increased the yield by 50–168% for late sowing and 16–75% for early sowing. In conclusions, this study revealed that optimal timing for sowing and one-time irrigation applied only during water sensitive growth stage are good strategies to improve the productivity of rainfed crops in a drought-prone areas.