Effects of CO₂ Enrichment on Growth, Yield and Fruit Quality of Strawberry Grown with Rockwool

Abstract

This experiment was carried out to investigate the effects of CO₂ enrichment on growth, yield and fruit quality of strawberry (Fragaria×ananassa Duch. cv. Ai-Berry) grown with two types of rockwool (RW : slub and granule) . The growth and development of plants were hastened in flowering date, maturing days and harvesting date by CO₂ enrichment in both RW media. Between the RW media, the growth was more vigorous and yield was higher in granule compared to those in slub. CO₂ enrichment increased total yield by 50 and 30% in RW slub and granule, respectively. Soluble solid content and titratable acidity of fruits were also increased by the CO₂ enrichment. Although the leaf area of plants grown with CO₂ enrichment was larger compared to the control, the rate of water absorption was almost equal. The electric conductivity of nutrient solution was also markedly decreased by CO² enrichment. In midwinter, the CO₂ concentration in the control greenhouse was lower than outside especially on fine and cold days, and much lower than those in the usual soil cultured greenhouses. Because in greenhouses for soilless culture where no organic substance is applied, only a small amount of CO₂ can be expected to be supplied from the soil, CO₂ enrichment may be necessary when strawberry plants are grown without soil.