EFFECT OF VARYING LEVEL OF NITROGEN AND POTASSIUM CONCENTRATION IN THE NUTRIENT SOLUTION ON THE YIELD AND LEAF COMPOSITION OF DRIP-FERTIGATED TOMATOES
The effects of nitrogen (N) and potassium (K) concentrations of the nutrient solution on yield and leaf composition of greenhouse-grown and drip-fertigated tomatoes (F-144 cv) were investigated in a 2-year study. Four levels of nitrogen (0, 125, 250 and 375 mg N/l) and potassium (0, 150, 300 and 450 mg K/l) were tested. Also, 50 mg Mg/l and 2.5 mg Fe/l were applied to all replicates. Nutrient solutions were applied with irrigation water via the trickle irrigation system throughout the growing season. The highest yield (166.5 tons/ha) was obtained from levels of 250 mg N/l and 300 mg K/l levels. Increasing nitrogen up to 250 mg N/l increased total fruit number, but potassium had no effect. The average fruit weight was decreased where increasing nitrogen and potassium levels increased soil salinity of the root-zone (above 2.5 dS/m). The nutrient content of the leaves was significantly affected by nitrogen and potassium levels. N, K, Mg and Fe contents in leaves increased significantly with increasing nitrogen level up to 250 mg N/l, whereas P, Zn, Mn and Cu were reduced. Increasing potassium level led to increase in K, but a decrease in Mg and Ca contents of the leaves. While N, P and K contents of the leaves decreased in time, Ca and Fe increased.
These results show that 250 mg N/l and 300 mg K/l in nutrient solution were sufficient to obtain the highest marketable yield for greenhouse-grown drip-fertigated tomatoes. Above these levels there was no additional advantages in terms of yield and leaf nutrient content.
Güler, S. and Güzel, N. (1999). EFFECT OF VARYING LEVEL OF NITROGEN AND POTASSIUM CONCENTRATION IN THE NUTRIENT SOLUTION ON THE YIELD AND LEAF COMPOSITION OF DRIP-FERTIGATED TOMATOES. Acta Hortic. 506, 81-86
Lycopersicon esculentum, drip irrigation, leaf nutrient content