Mechanical Cassava Harvesting as Influenced by Seedbed Preparation and Cassava Variety

Abstract

<abstract><title><italic>Abstract. </italic></title> 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 its industrial demand and 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 labor 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 assess the response of five different cassava varieties to mechanical harvesting on ridged and flat landforms. Results from field trials using the tek mechanical cassava harvester showed that best performance was achieved on ridged landforms, which have better tuber yields and root tuber orientation. Among all the cassava varieties, “Nkabom” was generally found to more easily lend itself to mechanical harvesting due to its bunchy nature. The tek mechanical harvester worked best on fields with minimal trash or weeds and relatively dry soils with moisture content from 12%-16% d.b. and requires drafts of up to 10.33 kN with penetration depth from 23 to 29 cm. Best harvesting performance was achieved at a tractor speed of 5 km/h giving a field capacity of 1.9 to 2.5 h/ha. After mechanical harvesting, the field is left plowed with savings on fuel, time and cost. However, it is recommended to field evaluate the harvester in all agro-ecological zones and through a wide range of soil moisture regimes in Ghana to determine suitable areas for mechanical harvesting and to promote nationwide adoption.