International Journal of Agricultural Science Research Vol. 4(3), pp. 039-048, March 2015 ISSN 2327-3321 ©2015 Academe Research Journals

Full Length Research Paper

Assessing impacts of climate change on tef (Eragrostis tef) productivity in Debrezeit area, Ethiopia

Araya A.¹*, Atkilt Girma¹, Tsedale Demelash², Lucieta Guerreiro Martorano³, Hailay Haileselassie¹ and Amanuel Zenebe Abraha²,

¹Mekelle University, College of Dryland Agriculture and Natural Resources, P. O. Box: 231, Mekelle, Ethiopia.

²Mekelle University, Institute of Climate and Society, P. O. Box: 231, Mekelle, Ethiopia.

³Embrapa Eastern Amazon, Belem, Para, Brazil.

*Corresponding author. E-mail: arayaalemie@gmail.com. Tel: +251914722576.

Accepted 11 February, 2015

Abstract

Tef is one of the major staple food crops in Ethiopia. Tef productivity in semi arid areas has been limited by climate variability. Drought and other extreme climatic events are expected to increase under the future climate. However, the impact of climate change on tef yield has not been adequately documented. The objective of this study was thus to assess the impacts of climate change on tef productivity. Climate outputs from five General Circulation Models (GCMs) ("ACCESS1-0", "bcc-csm1-1",  "CCSM4", "GFDL-ESM2M", and "HadGEM2-ES") with two Representative Concentration Pathway (RCP4.5 and RCP8.5) scenarios over three time periods: near (2010 – 2039), mid (2040 – 2069) and end term (2070 – 2099) periods were used as data input in a calibrated AquaCrop model for simulating future tef yield under three sowing dates: early (July 18), normal (July 28) and late (August 19). Results of the model simulation showed that tef yield under climate change varied substantially with sowing date, time period, RCPs and GCMs. Median yields increased and decreased by up to 10% and 39% for early and late sowing, respectively during the end term period whereas it reduced by up to 4% and 50% for early and late sowing, respectively during the near term period. The main reason for the slight increase in yield with early sowing was due to efficient use of rainwater over the growing period; relatively conducive early seedling establishment and better synchronization of the crop growing cycle with the rainy period. Contrarily, late sowing showed an overall significant yield reduction which could be attributed to poor synchronization of the rainy period with the growing cycle of the crop (especially exposure to long dry period after the reproductive period). Simulated yield for the end term period was also relatively higher compared to the mid and near term period. This could be due to the increased positive impacts of CO₂ as a result of increased CO₂ concentration towards the end term period. Among the climatic factors, rainfall distribution and amount will have the greatest impact on tef yield under future time period. Early sowing should be considered as an adaptation strategy for tef under future climate.

Key words: Climate change, tef, Debrezeit, sowing date.