Mature green fresh market tomatoes have been machine harvested on a commercial scale in California since 1978. The harvesting and handling process results in some damage to the fruit, and the incidence of puncture injury is a function of the percentage of fruits which retain their stems. This paper reports on a study to identify concepts for mechanically stemming the tomato fruits, concepts which, preferably, might be incorporated in the harvesting machine, so that machine productivity could be increased while maintaining or possibly reducing the size of crew required in the field. Parallel rollers were used to study fruit stem orientation and stemming of mature green fresh market tomatoes. Stemming efficiencies of more than 95% were achieved by using a padded, tri-roller assembly with a fruit constraining bracket.
The primary objective of the investigation was to evaluate the effects of induced perturbations in air temperature on the development of the tomato plant, while correlating a plant feature for use with machine vision non-contact sensing technologies, and allow for eventual integration into a non-invasive plant-based environmental control system. Real-time information of plant growth responses to steady-state and changing air temperature regimes were measured (i.e. dry weight). There was a positive correlation of the profile machine vision images with dry weight. Therefore, machine vision could be used for plant developmental predictions and development of a control system for maintaining plant schedules. © 1998 Society of Automotive Engineers, Inc.
To compliment the current subirrigation systems used for production of potted plants, a nutrient-flow wick culture (NFW) system was developed and compared with other subirrigation systems, such as an ebb and flow culture (EBB) system and a nutrient-stagnant wick culture (NSW) system in relation to their system characteristics and plant growth. Kalanchoe (Kalanchoe blossfeldiana cv. New Alter) was cultivated in a 6 cm pot for 10 weeks in each subirrigation system. The water-absorption pattern of the medium, water content of the medium, water loss, algal growth, salt-buildup and plant growth under various culture systems were observed. The water contents of medium under the NFW and EBB systems showed fluctuations from 30 to 40% and from 50 to 60% (by volume), respectively, whereas the water content under the NSW system gradually increased to over 40% without fluctuation. Relative to other systems, the water loss in the NFW system was 50-70% due to the reduction in the evaporation from the surfaces of the trough and medium. Algae appeared in the NSW system because the nutrient solution was always stagnant in the trough, while it was not observed under the NFW system. The dissolved oxygen in the nutrient solution was the highest during the irrigation period and the salinity in the medium was the lowest in the NFW system. With regard to system characteristics, the NFW system was simple, water-saving and efficient. In addition, the growth of kalanchoes in the NFW system was similar to those in the NSW and EBB systems at an irrigation frequency of five times a day. © 2005 Elsevier B.V. All rights reserved.
A closed loop transportation and elevation system for greenhouse crop production benches was designed and tested. Its purpose was to improve access to tomato plants in production. The system met two major design criteria: (1) benches could be elevated, and (2) benches could be interchanged between any two rows within a greenhouse bay. The system consisted of aluminum transportable benches, a pipe track system, transfer-elevation device (TED), and two rear transfer mechanisms (RTM). The centralized work station within the bench transport system, provided the possibility of performing labor studies to evaluate the system/labor interactive performance of the overall production process. The relative comparison of the operation times required for each operation for an elevated versus a non-elevated bench was evaluated and a measure of the relative bench transport time was determined.
Comparison of three evapotranspiration models for a greenhouse cooling strategy with natural ventilation and variable high pressure fogging. Villarreal-Guerrerero, F., M. Kacira, E. Fitz-Rodriguez, R. Linker, Ch. Kubota, G. A. Giacomelli, R. Linker, A. Arbel. 2011. Comparison of three evapotranspiration models for a greenhouse cooling strategy with natural ventilation and variable high pressure fogging.