Chamomile harvesters: A review

The large-scale production of chamomile (Matricaria recutita L.) in developed countries can be realized only by the mechanization of the harvest process. Based on literature sources and patent databases, the current status of picking principles was analyzed and systematized in this study. Taking into account the practical use of chamomile harvesting principles, it can be concluded that linearly moved picking combs with additional stalk cutting, rotating picking combs with central and outside discharge of flowers, and rotating pin drums are used most widely. Taking into account the flower quality and picking efficiency, rotating picking drums with comb sections achieve the best results. The most important reason for quality losses was the load on the flowers due to wiper blades for reducing the stem length. The limitation of the picking efficiency was caused mostly by the defined maximum drum rotation speed to ensure the discharge of picked flowers from the combs. The maximum drum rotation speed was a result of the ratio of gravity and centrifugal forces on flower heads for a given drum diameter. For improving chamomile harvesters, the authors preferred an increase of the ground speed instead of a higher working width to achieve a higher productivity. However, due to the increased ground speed. the rotation speed of the picking drum has to be increased simultaneously to reduce the feeding depth for single comb strokes. To develop a new chamomile harvester for commercial use, further scientific investigations are necessary to perfect the picking principle in detail and incorporate solutions for the conveying, storage and discharge of flowers. (C) 2011 Elsevier B.V. All rights reserved.