Technical and Economical Comparison of Onion Diggers with and Without Sifting Mechanism

Attaching a side-mounted furrower diggers makes it possible to use a rear-mounted machines for digging onion bulbs in broadcast planted farms, avoiding wheeling damages. For this purpose, two types of onion diggers, with and without sifting mechanism have been developed. To compare these machines from technical and economical point of view, an experiment was conducted based on randomized complete block design in Faridan region of Isfahan province, Iran. Results showed that the rod type digger due to inconsistent working depth causes the product weight loss of 2.32%, which is non economical. The product weight losses were 0.15% and 0.16% in blade type digger and sieve chain type digger, respectively, which are negligible compared to that of rod digger. The required labour force for collecting the crop dug by blade type digger was 15% higher than that of chain type digger. The higher labour force in this machine was due to more time and accuracy needed for collecting of bulbs. The 15% saving in labour cost in chain type digger obtained in exchange with a higher purchase price which was three fold compared to that of blade type digger. The economical breakeven points for chain type digger and blade type digger were 5.27 and 1.76 hectares, respectively. In general, the chain type digger proved to be more recommendable for larger farms if high power tractors were available. However, the blade type digger with lower price, simple structure and lower maintenance cost can be a more appropriate option for small farm holders.