Performance evaluation of the TEK mechanical cassava harvester in three selected locations of Ghana
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Date
2011-06-15
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Abstract
Cassava (Manihot esculenta Crantz) is the world‟s third most important crop and an essential source of food and income throughout the tropics providing livelihood for over 500 million farmers and countless processors and traders. In Ghana, cassava contributes 22% of Agricultural Gross Domestic Product (AGDP) and is an emerging profitable industry crop. Large–scale cassava harvesting especially during the dry season is the greatest constraint to meeting its industrial demand through commercial production. Manual harvesting is slow and associated with drudgery and high root damage in the dry season. A mechanical harvester is needed to break the labour bottleneck associated with cassava harvesting. Research on mechanization of cassava production, however is very low especially in the area of harvesting and currently there exists no known mechanical cassava harvesters in Ghana. The main objective of this study was to test and evaluate mechanical cassava harvesters for three (3) agro-ecological zones in Ghana. Performance of six (6) prototype mechanical harvesters (TEK MCH 1 to 6) was evaluated against various manual harvesting methods for five (5) cassava varieties on ridged and flat landforms. Results from field trials of the harvesters showed that the best performance was achieved on ridged landforms, which have better tuber yields and spread both across and along the ridge. „Nkabom’ cassava variety on ridges gave the lowest average tuber damage of 9.91% when harvested mechanically. The mechanical harvesters worked best on ridged fields with minimal trash or weeds and relatively dry soils with moisture content from 1.0 – 16.0 % d.b, penetration resistance between 1.0 MPa and 3.99 MPa with bulk density from 1.56 - 1.68 g/cm3 and drafts of up to 12.3 kN, requiring a minimum tractor engine power of 40.4 kW (54 hp) with penetration depth from 20.7 cm to 30.1 cm. The best harvesting performance was achieved at tractor speeds of 4 - 7 km/h giving a field capacity of 1.55 - 2.96 h/ha. After mechanical harvesting, the field is left ploughed with savings on fuel, time and cost for the next season. It is however recommended to test the harvesters in other agro-ecological zones under a wide range of soil moisture regimes in Ghana to promote nationwide adoption.
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A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirements for the award of the Degree of Master of Science in Agricultural Machinery Engineering