Performance evaluation of prototype mechanical cassava harvester in three agro-ecological zones in Ghana
Large-scale cassava harvesting, especially during the dry season, is a major constraint to its industrial demand and commercial production. Manual harvesting is slow and associated with drudgery and high root damage in the dry season. Research on mechanisation of cassava production is very low especially in the area of harvesting, and currently there exists no known functional mechanical cassava harvesters in Ghana. The main objective of the study was to test and evaluate mechanical cassava harvesting techniques in different agro-ecological zones in Ghana. Performance of two prototype mechanical harvesters (TEK MCH 2 and 6) was evaluated against manual harvesting methods for field capacity, efficiency and root damage using two cassava varieties, namely ‘Afisiafi’ and ‘Bankyehemaa’, on ridged and flat landforms. Results from field trials showed prototype harvesters weighing 268 – 310 kg can achieve optimum performance on ridged landforms. When harvested mechanically, tuber damage ranges from 16 per cent to 27 per cent for both ‘Afisiafi’ and ‘Bankyehemaa’. The mechanical harvester works best on dry fields with moisture content from one per cent to 17 per cent db containing minimum trash or weeds, and develops average drafts of 10.86 kN whilst penetrating depths from 13 to 40 cm. Optimum mechanical harvesting performance was achieved at tractor speeds of 5 – 8 km h-1, fuel consumption of 15 – 19 litres ha-1, and a field capacity of 2 h ha-1. After mechanical harvesting, the field is left ploughed with savings on fuel, time and production costs. It is, however, recommended to test the harvesters for wear and durability in major agro-ecological zones and through a wide range of soil moisture regimes in Ghana to support nationwide adoption.