Assessing the impact of climate variability on maize yields in the different regions of Ghana—A machine learning perspective

Empirical evaluation The descriptive statistics of maize yield are shown in Table 3. From the Table, the yield of maize ranged from 0.33 MT/Ha in 1992 in the Upper West Region to a maximum of 5.57 mt/ ha in 2019 in the Greater Accra Region. The average yield of maize varied across all the regions. The highest (2.01 MT/Ha) and lowest (1.17 mt/ha) average maize yields were detected in the Eastern and Greater-Accra regions, respectively. This indicates that the production of maize was more stable in the Eastern Region than in the Greater Accra Region. To compare the variability of maize yield in all the Regions in Ghana, the coefficient of variation (CVar) is employed. From the coefficient of variation as shown in Table 3, Around the mean maize yield of 1.17 mt/ha, the Greater Accra region has the largest coefficient of variation (CVar), at 77%. This implies that the yield of maize in this region is subject to significant variability over time. In comparison to other regions, the yield of maize in the Greater Accra region exhibits a more annual uneven performance. The Western region, on the other hand, exhibits the lowest coef- ficient of variation (CVar), which is 8% around the mean yield of 1.40 mt/ha. This suggests that compared to other regions, maize output in the Western Region is more consistent and has lesser variability over time. This means that a more dependable and predictable production pattern is shown by the constancy of maize yield in this region. Although there is a lot of variability in the Greater Accra region, it is vital to remember that

its mean yield (1.17 mt/ha) is lower than that of all the regions in Ghana (see Table 3). This indicates that, on average, the Greater Accra region produces less maize than the other nine (9) regions. Low average yield and high variability indicates that there may be difficulties or variables affecting maize cultivation in the Greater Accra region that cause both low average yield and high yield variability. Therefore, future research should analyze the variables affect- ing maize yield in this region (Greater Accra Region). Analysis of the climate variables. Climate variables are essential for understanding and appreciating the dynamics of climate patterns and environmental conditions in different regions. Analyses of climate variables such as average temperature, maximum temperature, minimum temperature, precipitation, and CO2 levels, provide vital insights into the changes and trends that influence Ghana’s maize yield. We can quantify the central tendency and rela- tive variability of these climate variables using key statistical measures such as the coefficient of variation and mean. The extent of fluctuations in temperature, precipitation, and carbon diox- ide levels is analyzed by looking at the coefficient of variation and mean as shown in Table 4. Table 4 shows the mean and coefficient of variation for each climate variable across Ghana’s regions. Table 3. Descriptive statistics of the maize yield for each of the regions in Ghana. Region Count Min Max Mean CVar (%) Ashanti 28.00 1.13 3.02 1.57 26.0 Northern 28.00 0.60 1.97 1.34 26.0

Eastern 28.00 1.36 2.98 2.01 22.0 Volta 28.00 0.99 2.36 1.65 18.0 Central 28.00 0.80 2.82 1.73 30.0 Upper East 28.00 0.50 2.98 1.36 37.0 Upper West 28.00 0.33 2.69 1.53 29.0 Brong Ahafo 28.00 1.41 2.45 1.88 12.0 Greater Accra 28.00 0.62 5.57 1.17 77.0 Western 28.00 1.03 1.55 1.40 8.0 https://doi.org/10.1371/journal.pone.0305762.t003 PLOS ONE Impact of climate variability on maize yields in Ghana PLOS ONE | https://doi.org/10.1371/journal.pone.0305762 June 25, 2024 11 / 24