Constantinos A. Tsatsarelis

A yield mapping system for hand-harvested fruits based on RFID and GPS location technologies: field testing

It is proposed that radio frequency identification (RFID) technology be used to overcome the limitations of existing yield mapping systems for manual fresh fruit harvesting. Two methods are proposed for matching bins—containing harvested fruits—with corresponding pairs of trees. In the first method, a long-range RFID reader and a DGPS are mounted on an orchard tractor and passive low-cost RFID tags are attached to the bins. In the second method, the DGPS is not used and RFID tags are attached to individual trees as well as bins. An experimental evaluation of the accuracy and reliability of both methods was performed in an orchard. The first method failed in half of the trials because the tree canopies interfered with the GPS signal. The RFID reader miss ratio for the detection of the bins was 0.32% for both methods. However, the attachment of RFID tags on suitable tree branches (to achieve 100% detection), in the second method, is not a well-defined procedure; some trial is demanded to determine the best positions and orientations of the tree tags in order for the RFID reader to successfully detect them. The first method seems more promising if robust tractor location under foliage can be achieved.

Energetics of baled alfalfa hay production in northern Greece

Abstract An energetic analysis of baled alfalfa hay production in northern Greece is presented. A total sequestered energy of 116 000 MJ ha −1 for the total production life (4 years) and the establishment was calculated. The most energy demanding operation was irrigation and the major input fuel and electric energy of the pumping system. Alfalfa hay yield was 45 900 kg ha −1 throughout the 4 year production period, i.e. 11 475 kg ha −1 per year, which corresponded to a total energy output of 725 000 MJ ha −1 . A mean energy efficiency of 6.25, satisfactory for the production and irrigation system used, and productivity of 0.396 kg MJ −1 was found. The interesting variation of the energy inputs, outputs, energy efficiency, productivity and intensity through the four production years are presented and discussed.