Energy Requirement for Manual Cassava Harvesting on Coarse Textured Soils in Ibadan, Nigeria

Most cassava farmers in Africa rely solely on manual means of harvesting root and tuber crops due to low level of mechanization. Evaluating the energy required in harvesting cassava and soil properties could guide farmers’ decision on stress-free harvesting options and practices. Experiments were conducted at the University of Ibadan (UI) and the International Institute of Tropical Agriculture (IITA) to establish the relationship between energy required in harvesting cassava and soil physical properties. The experiments were laid out in a randomized complete block design with four replications. Salter suspended scale model 235 was used to take energy measurements, while data collected were subjected to analysis of variance at α = 0.05. Mean yields from the two locations showed that variety TMS 97/0162 had the highest tuber mass (50,450 kg ha-1) followed by varieties TMS 30572, TMS 98/0505 and TMS 98/0510 (32,200–26,500 kg ha-1) and least by TMS 99/2123 (8,000 kg ha-1). There was a positive relationship between cassava yield and work done (R2= 0.21) at both locations, suggesting that yield affects the energy requirement in cassava harvesting. Soil moisture content showed a negative relationship with work done (R2= 0.52 and 0.24 at UI and IITA, respectively), indicating that increase in soil water reduces the force of harvesting. Also, soil bulk density had a negative relationship with work done (R2= 0.19 and 0.06 at UI and IITA, respectively). Energy required for harvesting cassava planted on coarse-textured soils could be reduced under high soil moisture content and bulk density conditions.