Development and Performance Evaluation of an Abrasive Wear Testing Equipment for Tillage Tools

The wear of tillage tools is a major source of economic constraints to local farmers. Estimating wear in the field is time consuming and expensive. Abrasive wear testing machines developed in advanced countries are not available in Ghana. This makes the study of wear related problems at laboratory levels difficult in the country and most third world research laboratories. The main objective of this study was to develop and evaluate equipment for testing the abrasive wear of tillage tools in the laboratory. The equipment consists of a circular soil bin, support frame, power transmission system and arm-subassemblies. The equipment was evaluated using a caststeel ploughshare in soils from KNUST (Anwomaso Research Farm, 69% sand), Wenchi (67% sand), Ho (73% sand), Mampong (68% sand) and Akatsi (83% sand), all in Ghana. The wear experiment was arranged in a completely randomized design with the soils from the five sites as the treatment. Each treatment was replicated five times. The wear rate of soils from Akatsi and Ho showed increasing trend with increasing moisture content while that of Wenchi and Mampong showed a reverse trend up to 13% and 15% moisture content, respectively. The soil from Akatsi produced the highest wear of 4.11g. The wear in the soils from Ho, Mampong, Wenchi and KNUST were 3.16g, 2.90g, 2.88g and 1.36g, respectively with the least wear from the KNUST soil. This confirms the long held belief that the wear rate of tillage tools is directly related to the sand content of the soil. The abrasive wear characteristics of the soils showed strong correlation between mass loss and dimensional loss of the ploughshare.Keywords: Abrasive wear, tillage tool, sand fraction, moisture conten

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