Leaching of Nitrogen from Container Plants Grown under Controlled Fertigation Regimes

One-year-old Weigela and Campanula liners were transplanted into containers and grown outdoors for one season. Nutrient solutions with high conductivity (EC: 2.0 dS/m), intermediate conductivity (EC: 1.25 dS/m) or low conductivity (EC: 0.95 dS/m) were applied at each irrigation. The nitrogen concentrations of the solutions were 220, 110 and 55 g N/m3, respectively. Fertigation frequency was controlled by the use of tensiometers placed in the growing medium. Growth and the amount of N leached from the containers and the N content of the shoot were measured. The respective amounts of N leached from Weigela were 40, 6 or 3 kg N/ha, whereas in Campanula 88, 45 or 17 kg N/ha was leached. The recovery of nitrogen applied was between 53% to 73% in Weigela and 41% to 56% in Campanula. The amount of non-recovered nitrogen was substantially higher in treatments 1.25 dS/m and 0.95 dS/m than in 2.0 dS/m. Fresh and dry weights of both plant species and the number of flowers in Campanula were reduced when the plants were grown at low conductivity.