Effects of Stem Moisture Content, Length of Lever Arm, Region of Cut and Cutting Attempts on the Cutting Efficiency ofa Push-Type Cassava Stem Cutter and Harvester

Abstract

Cassava harvesting is viewed as the most arduous operation in its production chain, involving three main sequential operations from stem cutting, soil loosening and then uprooting of the tubers. A semi-mechanised cassava stem cutter and harvester was developed to aid mitigate the drudgery involved in cassava harvesting. The machine was designed to carry out three main operations which include stem cutting, soil loosening and tuber harvesting. A precise knowledge of agronomic, physical and mechanical properties of the stem and factors affecting cassava harvesting most especially stem cutting plays a vital role in an attempt to overcome the existing challenges associated with the harvesting. The effects of stem girth, region of cut, cutting attempts and stem moisture content on cutting efficiency was investigated. The result of the experiment revealed that the cutting efficiency ranged from 3 to 99.5%. The highest cutting efficiency of 99.5% was obtained from combination of stem moisture content of 85%, length of lever arm from fulcrum of 65 cm, region of cut above ground level of 30 cm and number of cutting attempts 3. The lowest cutting efficiency of 3% was obtained from combination of stem moisture content of 45%, length of lever arm from fulcrum of 65 cm, region of cut above ground level of 30 cm and number of cutting attempts 3. The optimization process produced solutions whose desirability equals to 1 and the selected (most desirable) condition was found to be: stem moisture content (75%), length of lever arm from fulcrum (70 cm), region of cut above ground level (40 cm) and cutting attempts (4), with cutting efficiency and desirability of 99.5% and 0.959 respectively. These findings are vital knowledge necessary in the development of cassava stem cutting and harvesting equipment.