Climate change impact on wheat and maize growth in Ethiopia: A multi-model uncertainty analysis

Abstract

Ethiopia’s economy is dominated by agriculture which is mainly rain-fed and subsistence. Climate change is expected to have an adverse impact particularly on crop production. Previous studies have shown large discrepancies in the magnitude and sometimes in the direction of the impact on crop production. We assessed the impact of climate change on growth and yield of maize and wheat in Ethiopia using a multi-crop model ensemble. The multi-model ensemble (n = 48) was set up using the agroecosystem modelling framework Expert-N. The framework is modular which facilitates combining different submodels for plant growth and soil processes. The multi-model ensemble was driven by climate change projections representing the mid of the century (2021–2050) from ten contrasting climate models downscaled to finer resolution. The contributions of different sources of uncertainty in crop yield prediction were quantified. The sensitivity of crop yield to elevated CO2, increased temperature, changes in precipitations and N fertilizer were also assessed. Our results indicate that grain yields were very sensitive to changes in [CO2], temperature and N fertilizer amounts where the responses were higher for wheat than maize. The response to change in precipitation was weak, which we attribute to the high water holding capacity of the soils due to high organic carbon contents at the study sites. This may provide the sufficient buffering capacity for extended time periods with low amounts of precipitation. Under the changing climate, wheat productivity will be a major challenge with a 36 to 40% reduction in grain yield by 2050 while the impact on maize was modest. A major part of the uncertainty in the projected impact could be attributed to differences in the crop growth models. A considerable fraction of the uncertainty could also be traced back to different soil water dynamics modeling approaches in the model ensemble, which is often ignored. Uncertainties varied among the studied crop species and cultivars as well. The study highlights significant impacts of climate change on wheat yield in Ethiopia whereby differences in crop growth models causes the large part of the uncertainties.

Determining optimum plant density and nitrogen rate using field experiment and model simulation

“…61%, 0.92, 0.85 and 1.41 days, 1.31%, 0.99 and 0.91, respectively (Table3). Similarly, a close agreement was observed between the simulated and observed anthesis and maturity dates(Araya et al 2019;Rettie et al 2022). The model simulated anthesis and maturity dates with RMSE and nRMSE lower than 2 and d values greater than 0.85, respectively, for wheat in Ethiopia.…”

Crop production in northwestern Ethiopian highlands under changing climate

“…The decadal trend finding suggested that tef and barley yields were growing, whereas wheat and faba bean yields were dropping in Farta district (Figure 12). Climate variable both negative and positive relationships with crop yields reported by many scholars (Abera et al, 2018; Alaminie et al, 2021; Ginbo, 2022; Rettie et al, 2022; Wakjira et al, 2021). The result revealed that there was a nonsignificant negligible negative and weak positive correlation between tef yield with the annual rainfall (−0.229) and minimum temperature (0.348), respectively, in Yilmana Densa district (Table 9).…”

“…Changes in land and water regimes will have an effect on agricultural productivity as a result of the changing consensus of climate elements such as temperature and precipitation. The agricultural dependency GDP and low adaptive capacity of the African countries' climate change are severely affecting them (FEWS NET, 2022;Mahrous, 2019;Samuel et al, 2021;Thomas et al, 2019).…”

“…Like other African countries, Ethiopia's agricultural economy is impacted by climate change. Droughts and floods are two climatic factors that have a bigger effect on agricultural productivity in Ethiopia (Thomas et al, 2019). Climate change will be adversely affected cereal crop production in the future than in the past in Ethiopia.…”

Climate Change and Sweet Potato Production; Empirical Insights from Ebonyi State, Nigeria

“…Based on economic theories on food demand and supply gap, which posit a greater demand on food commodities against low supplies, calls for immediate actions and policies to sustain food production and security in the state are increasingly relevant. However, this study differs from previous studies on cereal crops such as rice, wheat, maize, sorghum, and tuber crops such as cassava, yam, cocoyam, (Boansi, 2017;Wang et al 2018;Asfew &Bedemo, 2022;Rettie et al, 2022;Mariem et al, 2021) because it focuses on sweet potatoes. Sweet potatoes are one of Nigeria's under-exploited and forgotten food crops which contributes significantly to Nigeria's gross domestic product, as the country is the major producer in Africa and second largest producer in the world.…”