Sweet potato production efficiency in Nigeria: Application of data envelopment analysis

This study examined Sweet Potato (SwP) production efficiency in Nigeria. A multi-stage sampling technique was employed in selecting 93 SwP farms in February, 2016. Data on farm and farmers' characteristics, input and output quantities and prices, constraints to SwP production among others were collected using pre-tested, well-structured questionnaire. The data were analysed with descriptive statistics, Data Envelopment Analysis (DEA) and Tobit regression. The results of the analysis revealed that the mean Technical Efficiency (TE), Allocative Efficiency (AE), Economic Efficiency (EE) under Constant Return to Scale (CRS) assumption were 0.685, 0.445 and 0.301 respectively. On the other hand, the TE, AE and EE under Variable Return to Scale (VRS) assumption were 0.783, 0.604 and 0.467 respectively. The Scale Efficiency (SE) was found to be 0.877. The results indicate that access to credit increased TE of farms by 3.5%. Regular training of SwP farmers increased their AE by 10.5% and EE by 16.6%. Access to credit by farmers decreased SE of farms under CRS and VRS by 1.9% respectively. Labour shortage, poor access to improved technology and infestation by insect pests were the three most important constraints limiting SwP production in the study area. Therefore, improving the efficiency of SwP production will require policies that will see to regular training of farmers by extension agents and other stakeholders and enhancement of rural farmers' access to credit.