Quality of water used for drip irrigation and fertigation of horticultural plants

In the years 1997-2008, 131 water samples were analysed. The concentration of N-NH₄, N-NO₃, P, K, Ca, Mg, Na, Cl, S-SO₄, Fe, Mn, Zn, Cu, B, and HCO₃ - was measured. In addition, the pH value and the electrolytic conductivity (EC) were determined and the sodium adsorption ratio (SAR) was calculated. The assessment of water was done on the basis of the classifications of water for the irrigation of greenhouse crops grown in soil or traditional media. According to guide values, water samples had to have high concentration of ions, especially HCO₃, Mg, Na and K. The questioned quality in about one half of the water indicates that the limits proposed by different researchers are too restrictive. The criteria to be met by water admissible for irrigation and fertigation should take into consideration the regional differences in water characteristics. The adaptation of recommendations elaborated on the basis of analyses originating from other geographical and geological regions can lead to the elimination of waters possessing favourable quality parameters. For irrigation of field and greenhouse crops, the following concentrations of components in water might be recommended as safe ones: 30 mg N-NO₃, 100 mg K, 150 mg Ca, 50 mg Mg, 100 mg Na, 100 mg Cl and 100 mg S-SO₄ in 1 dm³. For soilless culture fertigation in an open system, the maximum ion concentrations in water cannot exceed the recommended ones in the nutrient solution for the given plant. Also, the EC value should be taken into consideration.