Abstract
Raising crop yield per unit land area remains a key to eliminating food shortages given limited land resources. However, Africa still falls far behind other continents in crop yield and there is major variation across regions within Africa. This paper analyzed regional yield gaps and yield convergence in Africa for four major crops: maize, millets, sorghum, and cassava. The club convergence test was employed to test whether yields are converging in Africa. Our results found no evidence of population convergence as a whole for any of the crops. However, we found that crop yields are converging into several clubs or groups of countries, implying successful technology diffusion and use within, but not between, specific regions. Furthermore, we predicted the attainable output for the four crops based on club convergence using the highest actual yield in each club as the attainable yield for all countries in the same club, and found that the gap between actual output and attainable output is narrowing gradually. Nevertheless, actual output could still increase by 70% if all countries reached the yield frontier, which we defined as the highest actual yield in each club. We suggest that policies aiming to end hunger in Africa should focus on eliminating barriers to technology diffusion and use of agricultural support mechanisms between countries, particularly those in the same club.
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Notes
If there is no convergence for the whole sample, it can be that countries converge into several different steady state levels, which are named as convergence clubs (Phillips and Sul 2007).
The ranking is based only on the last fraction rather than whole period, that is because the yields in the last fraction are more similar to the long-run steady-state level. Therefore, regions with higher yields in the last fraction are more likely to be in the core group. Using the last third or half to rank the yield of all countries can significantly reduce the number of steps needed for identifying convergent clubs according to the simulation by Phillips and Sul (2007). Using different fractions for ranking will get the same results, but starting with the last fraction can shorten the time used for the convergence test.
Output gap is defined as “The gap between attainable and actual output”.
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Tian, X., Yu, X. Crop yield gap and yield convergence in African countries. Food Sec. 11, 1305–1319 (2019). https://doi.org/10.1007/s12571-019-00972-5
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DOI: https://doi.org/10.1007/s12571-019-00972-5