Elevated carbon dioxide and substrate composition affect growth, nutrient uptake, and water use efficiency in blueberry cultivation under greenhouse

Blueberries (Vaccinium corymbosum L.) are a valuable crop with growing demand due to their nutritional and health benefits. Optimizing their cultivation under controlled environmental conditions as the use of supplemental carbon dioxide (CO2), offers a promising avenue to enhance growth. However, the interaction between elevated CO2 levels and substrate composition on physiological parameters and nutrient dynamics in blueberry plants remains underexplored. Therefore, the objective of the present study was to investigate CO2 supplementation in the growth and production under controlled conditions in a greenhouse with different substrate composition. Physiological parameters, mineral composition, production, water use efficiency (WUE), nutrient use efficiency (NUE), and nitrite and nitrate concentration were determined in plants grown in 3 substrates with different physical-chemical characteristics. Results showed that CO2 (1000 ppm) positively influenced the growth and production of blueberry. The plants grown in the S2 (100% coconut fiber) or S3 (90% coconut fiber and 10% perlite) under elevated CO2 presented higher the photosynthetic rates. This result in relation to S1 (70% coconut fiber and 30% peat) attributed to the composition of the substrate. However, S1 or S3 presented higher WUE and NUE under elevated CO2, increase water use and carbon assimilation. Elevated CO2 did not increase macronutrients and micronutrients concentration in leaf and fruit. However, plants grown in S2 have a low nitrogen absorption and adaptation to assimilate. Therefore, the results indicate that the addition of perlite in S3 followed by peat in S1 were more suitable than S2 under elevated CO2, since the plants were able to absorb nitrogen and water more effectively providing higher yield in the S3.