Economic evaluation and intercropping indices of maize-common bean system under variable fertilization in Southwestern Ethiopia.

Maize-common bean intercropping is considered one of the strategies to increase productivity per unit area of land and improve the use of limited resources. Despite its widespread practice in southwestern Ethiopia, limited empirical evidence exists on its economic profitability. Therefore, the research was conducted to determine the profitability and economic performance of intercropping systems by using standard existing indices under two farmyard manure conditions (with and without), two planting patterns (1:1 and 1:2 maize: common bean rows), and four nitrogen (N) rates (0, 46, 92, and 138 kg N ha⁻¹), laid out as a factorial randomized complete block design with three replications. The results showed that the MAI, MRR, and yield increase (65,388.2 ETB ha⁻¹, 362%, and 16%, respectively) were obtained from the treatment FYM + 1:2 pattern + 138 kg N ha⁻¹, while the MRR (475%) was obtained from FYM + 1:1 + 46 kg N ha⁻¹. Also, maize showed higher Aggressivity, CR, and AYL values than common bean, indicating a stronger competitive ability as a result of increased N rate, with opposite trends for common bean, and IA of common bean was negative across most treatments. Aggressivity was also negative except at the 1:2 pattern at 0 kg N ha⁻¹, which indicates low competition from maize when no fertilizer was applied. However, FYM + 1:2 pattern + 138 kg N ha⁻¹ achieved the highest land-use efficiency and monetary advantage. Nevertheless, partial budget analysis indicated that FYM + 1:1 pattern + 46 kg N ha⁻¹ generated the most acceptable marginal rate of return (475%) and a net benefit of 59,250.43 Ethiopian Birr (ETB) ha⁻¹ under the study conditions. Therefore, this treatment is recommended for the study area due to its more attractive return on variable costs for farmers.