Various methods for reimbursing pickers have been employed worldwide, with most fruit growers now paying a piece-rate to small picking teams for bins (e.g. for pome fruit) or for buckets (e.g. for sweet cherries, blueberries).  Regardless, paying piece-rate is beset with inaccuracies that cause significant financial losses. Our tests in commercial sweet cherry and apple orchards revealed variability of 25 – 30% of final weight among bins and buckets. For example, in sweet cherry orchards a range of more than 50 kg in bin weights (mean bin weight~=200 kg) and 3 kg in bucket weight (mean bucket weight~=10 kg) were recorded during these trials. These discrepancies can cause significant economic losses. A cherry grower found that pickers were overpaid $16,663 in 2010 and 2011 because of the variability in bucket weights (M. Omeg, The Dallas, OR, USA, personal communication). Additionally, a blueberry grower in Prosser, WA (USA) estimated that pickers were overpaid $20,000 in one week (2013). There is no accurate system for calculating labor efficiency or reimbursing pickers individually.

In this paper, a portable Labor Management System (LMS) for paying fruit pickers individually and accurately is presented. This system utilizes a digital hanging-weight scale (S-type load cell) and a computational unit (CU). The CU consists of: (i) a microcontroller (arduino mega), (ii) a RFID reader; (iii) a thermal printer; (iv) a GPS module; (v) a wireless transceiver (Xbee pro); (vi) a display unit (LCD); (vii) real-time clock (RTC); and (viii) a memory card (sd card). Low-cost passive RFID wristbands, which contain unique ID numbers, are worn by pickers.  A hanging-weight system was developed in order to be self-levelling, an important factor for open field environments (e.g. sloped orchards). Each picker places their bucket(s) on the suspended platform and initiates the weighing system with their RFID-wristband by passing it before the reader. The LMS immediately calculates the weight of fruit, associates it with the picker ID, and prints a receipt that outlines the picker’s ID, date, time, bucket(s) weight, and accumulated weight (total weight). Additionally, all data are stored locally to an sd card and transmitted wirelessly to the cloud.

This portable LMS was field-tested for accuracy and reliability during commercial harvest of sweet cherries (Prunus avium L.) and blueberries (Vaccinium corymbosum) in the Pacific Northwest, USA. Using the LMS the overall accuracy of payroll was improved, by providing the ability to reimburse pickers individually, based on the actual weight of fruit they harvested. The economic benefits of paying for actual weight of harvested fruit will be discussed as well as the potential for this system to generate accurate yield maps and provide “in-field” traceability.