Submitted to: Ag Research Reports - Project Summary Reports
Publication Type: Research Technical Update
Publication Acceptance Date: August 3, 2009
Publication Date: January 15, 2010
Citation: Wang, D. "Design of a Field Raised-Bed Trough System using soilless Substrate for Strawberry Production in California". pp. 123-133.In 2009 Annual Production Research Report, California Strawberry Commission, Watsonville, CA. Interpretive Summary: Strawberry growers in California produce the most berry fruits in the U.S. However, the high yield and fruit quality depend on pre-plant fumigation for controlling soilborne pests and pathogens. Continued use of soil fumigation is subject to environmental regulations to protect air, water, and soil quality. There is a strong need for developing a fumigant-free production system for open field production of strawberries. Field trials were carried out at the Monterey Bay Academy (MBA) and a Santa Maria field site to test the feasibility of growing strawberries using raised-bed troughs filled with non soil based substrate materials. Different ratios of peat, perlite, coir, rice hull, and a redwood soil conditioner were used as the substrate media to fill the troughs. Two inverted triangular troughs per bed were used at the MBA site and two inverted half moon shaped troughs were used for the Santa Maria site. Field trials also include a clear and a green mulch variation in all substrate treatments. Plant canopy development and yield were measured during the 2009 season. Because of the much reduced rhizosphere for water and nutrient retention, autonomous irrigation and fertigation systems were designed, installed, and operated to deliver water/nutrient on demand. Each of these water management systems consisted of a weather station, an electrically-control flow monitoring and control system, a water and nutrient delivery and sensing network, and a computer program written for each site to operate autonomously to irrigate respective field plots. Efforts were also made to measure substrate water content and temperature under both mulch covers. Disease assessment was made at the termination of field trials. Preliminary data clearly showed that the irrigation systems worked as expected where multiple irrigations per day were accomplished and the cumulative amount of water application tracked closely with the seasonal evapotranspiration. Substrate water content and temperature also reflected each irrigation event or mulch colors. For the “Ventana” variety which was the only one that was completed at the time of this reporting, comparable fruit yield was obtained between different substrate media, except in peat where lower weight was measured. The data indicated a strong potential for commercially growing strawberries using non soil based substrate materials in raised-bed troughs.
Technical Abstract: There are a number of approaches for producing strawberry fruit on a commercial scale without fumigants. One possible approach is to grow strawberries using raised-bed troughs filled with non soil based substrate media. Field trials were conducted using peat, perlite, coir, rice hull, and a redwood soil conditioner as the growth media in commercial strawberry fields. Two types of troughs were use: inverted triangular troughs and inverted half moon-shaped troughs. A completely automated irrigation system was put together for delivering water to strawberry plants located in the troughs. Other measurements included substrate water content, temperature, plant canopy size, and fungal pathogen ratings. Results showed that reasonable yield and fruit quality were obtained in strawberries harvested from these artificial media filled troughs. Water management was more sensitive because of reduced root zone volume. Nutrient deficiency was observed in one field site where slow release fertilizer was likely depleted before the termination of the experiments. The next phase will focus on different rates of fertility and more combinations of substrate media.