Effects of CO₂ Enrichment on the Absorption of Water and Mineral Nutrients in Strawberry Grown in NFT

Abstract

This experiment was carried out to investigate the effects of CO₂ enrichment (700-800 ppm in the day time) on the absorption of water and mineral nutrients in strawberry (Fragaria × ananassa Duch. cv. Nyoho) grown by nutrient film technique. The concentration of major elements in the nutrient solution were NO₃^- : 5, NH₄⁺ : 1, H₂PO₄^- : 1, K⁺ : 3, Ca²⁺ : 1, Mg²⁺: 1 mmol·L^-1. Vigorous growth and high yield were obtained by CO₂ enrichment. In control (ambient CO₂, 200-400 ppm), the uptake concentration (each mineral absorbed per unit volume of water absorbed, n/w) was almost equal to the concentration of the solution, throughout growing period. However, under CO₂ enriched condition, n/w and total uptake amount of minerals increased by 30-60% compared to control, especially, from November to February when the temperature and light intensity were low. The n/w of minerals were also 50-100% higher than the concentration of the nutrient solution. Total-N concentration in leaves was markedly decreased by CO₂ enrichment, while there was little difference in P, K, Ca and Mg. To keep the concentration of nutrients in the solution, the concentration of nutrients should be kept 50-100% higher than those previously reported, when strawberry plants are grown with CO₂ enrichment.