Application of the constant soil temperature layer for energy-saving control of the local environment of greenhouse crops. I. Local control of the ambient environment of strawberry

In a farmer’s strawberry greenhouse, seasonal changes in solar radiation and air conditions (temperature, and CO 2 concentration) and it the stable year-round production of strawberry was depressed by low temperature and low solar radiation in the cold season and by excessively high temperature in early formations the nighttime and inappropriate application of CO 2 enrichment the depression of stable production. a local environmental control system developed for strawberry on air circulation and heat exchange between the constant soil temperature layer the ambient air. system an underground air pipe (UAP) and perforated inter-row air ducts (IAD) connected the UAP; UAP year-round drawn into the UAP, and the air flowing through the UAP exchanged heat with the constant soil temperature layer and was dispersed to the ambient environment of the strawberry crops through the perforated IAD. In the nighttime during the cold season, air flowing through the system was heated by 8°C, and a heating effect of 3°C was observed in the ambient air. The proposed system of applying the constant soil temperature layer can be expected to reduce the nighttime heating load by 50% and enable energy-saving environmental control.