Effect of nitrogen rate and water replacement level on leaf biomass production and leaf nitrogen concentration of ten pot-grown blueberry cultivars

Soilless blueberry (Vaccinium corymbosum L.) production is an alternative system that is increasing worldwide in surface area. There is little scientific information available as yet on the agronomic management of this cultivation system. The objective of the present study was to evaluate four N rates (0%, 100%, 200%, and 300% of the reference rate) and three water replacement level (70%, 100%, 130%) on leaf biomass production and leaf N concentration previous to winter fall (May and August 2021) in 10 pot-grown blueberry cultivars (Blue Ribbon, Duke, Camelia, Cargo, Last Call, Legacy, Ochlockonee, Suzie Blue, Ventura, and Victoria). An experiment was conducted in south-central Chile (36 degrees 55' S) with first-year plants. During the first growing season, results showed interactions between cultivars, N rates, and water replacement levels; there was a synergistic effect between N rates and water replacement levels on leaf biomass production in 'Duke', 'Camelia', 'Ochlockonee' and 'Suzie Blue'. Overall, the highest leaf biomass production in most cultivars was obtained with an N rate ranging from 33.2 to 53.1 g plant(-1) season(-1) (100% and 200% N rates, respectively) and 100% and 130% water replacement levels. Water consumption during the season fluctuated between 93.79 a 136.23 L season(-1). The highest leaf N concentration in most of the blueberry cultivars was obtained with N rates ranging from 33.2 to 53.1 g plant(-1) season(-1) and 70% and 100% water replacement levels. Therefore, agronomic management recommendations for N fertilization and water replacement levels in blueberries produced with this growing system cannot be generalized.