Comparison of Manual and Manual-cum-Mechanical Energy Uses in Groundnut Production in a Semi-arid Environment

A study was conducted to evaluate and compare the inputs of manual energy only and manual-cum-mechanical energy in the production of groundnuts (Arachis hypogaea) in a semi arid region of Nigeria. Two groups of randomly selected farms were considered, each consisting of five small-scale farms. One group was made of farms on which only manual energy was used (FME) in the production process. The second group, denoted as FMME, had both manual and mechanical energy inputs. To evaluate the energies invested, the following constants were used: (i) Manual energy of an adult male – 0.75 MJh-1 (10% less for a female adult); (ii) diesel fuel energy value – 47.78 MJL-1, (iii) energy for manufacture, transport and repair (MTR) of machinery – 100.7 MJkg-1. Results show that the maximum, minimum and mean energy inputs for the FME group were 1271.1, 617.5 and 1047.8 MJha-1 respectively. For the FMME category, the corresponding values were 2899.1, 1396.1 and 2285 MJha-1 respectively. The two groups of farms were comparable in two respects. In both, land clearing had the least energy requirements (4% and 1% of the mean total energy inputs of FME and FMME respectively). Also, weeding had the most energy requirement (45% and 52% of the mean total energy inputs were expended in weeding the FME and FMME farms respectively). For the FMME group, most of the energy expended was manual. Only 19% of the mean total input came from the mechanical source, which was rather too low from the mechanisation point of view. Ideally, mechanical energy should replace or significantly supplement manual energy in all operations, as it did in harrowing, the only mechanised operation for the FMME group where manual energy of the tractor operator was only 0.2% of the mean energy needed for tilling the land. The mean quantities of groundnuts (in shells) harvested from the FME and FMME groups were 598 and 655 kgha-1 respectively, while the mean values of the energies invested to produce a unit quantity of the crop in the two categories were 1.75 and 3.49 MJkg-1ha-1 respectively. It is recommended that further studies be conducted in order to relate yields with the types and intensities of energy invested in producing the crop.