Temperature control, fertilization management and long-day treatments are commonly implemented to achieve optimal growth control in strawberry (Fragaria ϫ ananassa Duch.). Control of these parameters has typically relied on visual evaluation of plants by producers. For advanced production control, it is necessary to continuously monitor growth and amounts of light received. In this study, we quantified the height of strawberry plants, and leaf area receiving direct sunlight in different leaf layers over time using Kinect, a depth sensor. Data from the sensor enabled evaluation of temporal changes in plant height and of the differences in the stratification of strawberry plants grown in greenhouses at two different low nighttime temperatures. The amount of light received by different layers of the entire plant community could be estimated from sensor measurements, and was directly correlated with yield and dry weight. Our results demonstrate that a depth sensor like Kinect can quantify essential information on strawberry growth and amounts of light received. Further improving the accuracy of measurement by sensors could lead to the development of effective cultivation management methods based on the amount of photosynthesis and growth of plants.

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The Great East Japan Earthquake heavily damaged horticultural production in the Tohoku Pacific Ocean coastal region of Japan. In this paper, we will describe the reconstruction support for strawberry production in Miyagi Prefecture that was damaged by the disaster. We have been involved in supporting horticultural reconstruction efforts in this region since the earthquake struck in 2011. In 2012, the Japanese Government began a research project to support reconstruction of the affected agricultural area ("A Scheme to Revitalize Agriculture and Fisheries in Disaster Area through Deploying Highly Advanced Technology"). The horticultural research station for the project, located in Yamamoto-town (Miyagi Prefecture), is a Venlo-type greenhouse 0.72 ha in area. Yamamoto-town and nearby Watari-town, together represent a major strawberry production region in Tohoku. Therefore, technical support to reconstruct the strawberry greenhouse facilities was a high priority of the research project. Since inception of the project, we have provided technical information to growers and the local extension service, and we have cooperated with them to solve technical problems. Due to the amount of salt accumulated in the soil after being flooded by the earthquake-related tsunami, we determined that an elevated growing-bed system was the best option to resume strawberry production. Therefore, we designed and proposed an elevated growing-bed system consisting of individual growing containers and a crown-temperature control system; this system should prevent the spread of soilborne diseases from occurring frequently in connecting long beds. Separate containers also provide the drainage needed to keep the root zone (air and water contents) amenable for growing strawberries. The crown-temperature control system, established by the National Agriculture Research Organization (NARO), was added to increase yield and reduce fuel consumption. Large-scale, multi-span greenhouses were constructed by the local government (total 152 growers, 41 ha) and the first strawberry cultivation restarted in September 2013. In the research station greenhouse, we have continuously demonstrated or developed new technologies and provided information to the growers.