Gene A Giacomelli

Abstract:

Floor heating is a promising technique to heat greenhouses using low quality energy. The large thermal inertia of floor heating systems requires some form of predictive control. To analyze the effectiveness of feedforward logic, first a prediction model has been developed and then an experiment using a controlled-environment chamber has been conducted. Basic control logic has been established and verified for controlling air temperature by energy input only to the floor. The combination of feedforward and feedback control should be the next step.

Abstract:

Transplanting tests with commercially grown seedling plugs were conducted using a Sliding-Needles with Sensor (SNS) gripper operated by a SCARA type robot. A total of 11 plug trays, with 600 cells each, were tested. Many mechanical and horticultural factors were found to affect the percentage of successful transplanting, which were analyzed to understand their influence on the effectiveness of the gripper. The mechanical factors were 1) the angles of gripper needles; 2) plug extraction acceleration; and 3) the sensor sensitivity. The horticultural factors included 1) empty cells on the plug trays; 2) plant species; 3) root connections; 4) adhesion between roots and cell walls; 5) root zone moisture; and 6) the number of seedlings in one cell.

Abstract:

An overview of the design considerations and the operational characteristics for production of tomato in a greenhouse in a semi-arid region is provided. The integration of the automation, culture and environment requires an understanding of the production needs of the crop, and the specialized weather conditions of the Arizona climate. The demand on the plant imposed by the greenhouse climate, including air temperature and humidity, or atmospheric vapor pressure deficit (VPD), leaf temperature, and solar radiation must be balanced with the water availability within the plant root zone, as affected by the electrical conductivity of the nutrient solution and the irrigation frequency. The crop production system requires that nutrient delivery be automated to provide a consistent availability of nutrient formulation and concentration in proportion to the general daily fluctuating water demand. An automatic means to determine water demand that will vary the irrigation frequency and the nutrient concentration is important to provide the desired stress for crop production. The climate control includes monitoring and feedback mechanisms to firstly, minimize the potentially harsh diurnal fluctuating desert conditions of low air humidity, high solar radiation, and water quality with high salts, and then, to secondly, alter the plant microclimate to match the stage of plant growth and its production condition. The greenhouse structure should be of sufficient height for buffer volume needed to offset the large daily environmental fluctuations. The structure system must also offer air exchange capacity, shading, and evaporative cooling to help maintain the desired air temperature and relative humidity for crop production. Experiences and research studies within each of these areas of production system, climate control and greenhouse structure will be presented, including: production of greenhouse tomatoes within a high-wire, continuous production system; modulating plant vegetative or reproductive tendency with a combination of root zone and aerial microclimates; improving fruit market quality; and greenhouse structure design variations for improved cooling and reduced water utilization.

Abstract:

The Controlled Environment Agriculture (CEA) technologies are helping in producing vegetables in the icy areas of Antarctica. The CEA-based hydroponic crop production processes used the abundant frozen fresh water, as an alternative food growth chamber to produce vegetables. University of Arizona and Sadler Machine Company, under the Controlled Environment Agriculture Program (UA-CEAC) designed and built the new South Pole Food Growth Chamber (SPFGC) under the direction of the National Science Foundation, which manages the US Antarctic Program. Antarctica provides an unique application for CEA technologies, which can grow plants anywhere, any time, with planning and resources.

Abstract:

One critical factor for crop energy conversion for plant growth is photosynthetically active radiation (PAR) received by the plant. While it is important to know their total solar radiation transmission characteristics in the design of greenhouse for thermal environment management, it is also essential to understand their PAR transmission capability, especially over the winter period for high-latitude regions. This paper presents the results of PAR transmission of four different greenhouse glazings, measured at both the glazing and crop canopy levels. The glazings studied were single glass, double glass, twin-walled acrylic and air-inflated double polyethylene. The first three materials were tested at a commercial rose greenhouse range (gable type) in Connecticut and the double polyethylene greenhouse (bow type) was located at Cook College, Rutgers University. Also reported is the comparison between total solar radiation transmission and PAR transmission in the double polyethylene greenhouse. The glazing level PAR transmission showed mainly the effects of glazing materials, sky clearness and solar angle of incidence, whereas PAR received at the canopy level was strongly influenced by the greenhouse geometric configuration and internal structures. It was found that air-inflated double polyethylene transmitted a higher percentage when measured in the total solar radiation range than in the PAR range. © 1987.