Abstract:
Potato (Solanum tuberosum L.) has become increasingly important food crop in developing countries. The impact of climate factors and potato crop growth/yield in changing climate is poorly understood in Ethiopia. Thus, this study mainly aimed to assess the impact of current and future climate on potato crop growth and yield using field experiment and model simulation during belg 2020. The experiments were conducted at Gircha Highland Fruits and vegetables Research Center Chencha district. Potato canopy cover and plant height were measured with high temporal resolution (twice per week) and yield parameters were assessed. Weather observations were obtained from an automatic weather station operational in the center. Future projected data for three models were obtained from the CORDEX database under RCP4.5 and RCP8.5 scenarios. Weather variables' influence on potato crop growth and yield during growing season was evaluated using statistical and mathematical data analysis approaches. Model sensitivity experiments were also conducted to further study the impact of weather variables on potato yield, to test optimum planting date and to analyze the significant weather variable (s) that affect potato yield. The highest plant height, canopy cover, tuber number, and yield were observed in the first two planting dates, while fourth planting date shows the least. Canopy cover and plant height were strongly correlated with Temperature sum (Tsum) and Cumulative incoming solar radiation (CISR). Observation and model sensitivity experiment shows that rainfall and SW↓ have positive effects on tuber number. Yet, increased rainfall decreases yield while yield increases with SW↓. Tuber DMC and CISR showed a positive correlation. Validation of the DSSAT SUBSTOR-Potato model revealed a good agreement between simulated and observed yield (R2=0.89 and RMSE=8.3 t∙ha-1). The first two weeks of February were the best period to plant potato in the area during belg 2020. The future climate in the region is projected to be warmer (1.1℃/decade) and rainfall change (±0.9 mm/year), ultimately resulted in yield decline (6.3 t.ha-1.decade-1). This adverse climate change effect should be investigated further using multi-crop models, and adaptation techniques such as adjusting planting dates may be required to assure food security in the area.
