Use of Reflective PAR Mulches to Enhance Winter-time Greenhouse Strawberry Production

摘要

Photosynthethically-active-radiation (PAR) has long been used by horticultural specialists and crop modelers to characterize the quantity and quality of light conducive to plant growth and development The spatial distribution of light within a double-polyethylene glazed plastic Quonset greenhouse can be quite variable and diffuse throughout the photoperiod, especially at low sun angles in the northern regions of the United States. Previous literature has reported 10-35% increase in canopy lighting using reflective plastics under various plants. A study was undertaken to evaluate the productivity of fourteen strawberry cultivars in a campus Quonset house during the winter months. Modified field of view LiCOR~(TM) PAR reflectance sensors, full hemispherical PAR incident sensors, and infrared thermocouple sensors (IRT/c) were mounted over gravel and five different color plastic backgrounds. PAR and mulch temperatures were recorded for several months using a wireless LabVIEWTh/Lbased sensor network within the greenhouse. Weather and the greenhouse environment were also monitored. The use of background reflective plastics or so-called reflective mulches to increase PAR and to capture heat within cap-mats was also studied. It was experimentally found that several of these cultivars will bear significant fruit and could be economically productive during winter.