Measuring the trends of growth and variability in agricultural production is important to understand how outputs change over time. Ethiopia is the largest producer of coffee in Africa and the fifth in the world. Despite the abundant opportunities and continuous efforts made to enhance its production, it is often said that the productivity of Ethiopian coffee remains far below its potential. Yet, empirical data on the status of coffee production over time in Ethiopia is scant. We, thus, analyzed the trend, instability, and decomposition of coffee production in Ethiopia for three periods, i.e., the entire period (1993-2019), the pre-Agricultural Growth Program period (1993-2010), and the Agricultural Growth Program period (2011-2019). In all three periods, harvested area and production showed an increasing trend while productivity showed a cyclical decreasing trend. The compound growth rates of harvested area (8.14%) and production (6.68%) in the 1993-2019 period were positive and significant at 1% level, whereas that of productivity (-0.45%) was not significant. Similarly, the compound growth rates of harvested area and production during pre-AGP (6.02 and 6.06%) and AGP (6.43 and 3.57%) were positive, but only significant during AGP, and that of productivity in both pre-AGP and AGP (0.19 and -1.6%) were not significant. Productivity was, however, more stable than harvested area and production during the entire and pre-AGP periods, while harvested area and production were more stable in AGP than in the other two periods. Besides, the harvested area effect on production differentials was substantial in all three periods, while productivity and productivity-harvested area interaction effects declined production during the entire and AGP periods. Overall, the results demonstrate that to enhance and sustain coffee production in Ethiopia, using improved varieties and agronomic practices can be a better option than expanding the cultivation area since land is scarce and fixed in supply.

衡量农业生产的增长和变异趋势对于了解产出如何随时间变化非常重要。埃塞俄比亚是非洲最大的咖啡生产国，也是世界第五大咖啡生产国。尽管有很多机会并不断努力提高产量，但人们常说埃塞俄比亚咖啡的生产力仍远低于其潜力。然而，关于埃塞俄比亚咖啡生产状况随时间推移的经验数据很少。因此，我们分析了三个时期埃塞俄比亚咖啡生产的趋势、不稳定性和分解，即整个时期（1993-2019）、前农业增长计划时期（1993-2010）和农业增长计划期间（2011-2019 年）。在这三个时期，收获面积和产量呈增加趋势，而生产力则呈周期性下降趋势。1993-2019年收获面积（8.14%）和产量（6.68%）的复合增长率在1%的水平上为正且显着，而生产力（-0.45%）的复合增长率则不显着。同样，AGP前（6.02和6.06％）和AGP（6.43和3.57％）期间收获面积和产量的复合增长率为正，但仅在AGP期间显着，而AGP前和AGP的生产力复合增长率（ 0.19 和 -1.6%）不显着。然而，在整个和 AGP 之前的时期，生产力比收获面积和产量更稳定，而 AGP 的收获面积和产量比其他两个时期更稳定。除了，在所有三个时期，收获面积对产量差异的影响都很大，而生产力和生产力与收获面积的相互作用效应在整个和 AGP 时期都降低了产量。总体而言，结果表明，为了提高和维持埃塞俄比亚的咖啡产量，使用改良品种和农艺做法可能是比扩大种植面积更好的选择，因为土地稀缺且供应固定。