THE EFFECT OF SLOWLY ACTING FERTILIZERS ON THE YIELD AND QUALITY OF MATURE STRAWBERRY FRUITS

Abstract

Effect of slowly acting fertilizers on the formation of yield and quality of mature fruits was investigated in the pot experiment with strawberry (variety Darselect). Experiment was established in year 2011 within the areal of Slovak Agricultural University in Nitra and consisted of 6 treatments with the same rate of nitrogen (1.65 g per pot) applied through different fertilizers. The 1st treatment: unfertilized control, 2nd treatment: quickly soluble fertilizer Duslofert Extra (DE), 3rd treatment: slowly acting fertilizer Duslocote (DC), 4th treatment: Duslocote with microelements, 5th treatment: mixture of DE (20%) and DC (80%), 6th treatment: application of urea-formaldehyde condensate. The highest yield of mature strawberry fruits (643,35 g/pot) was harvested from treatment 4 fertilized by Duslocote with microelements. Content of nitrates in fruits fluctuated from 56 to 65 mg.kg^-1 of fresh matter. Significantly lower content of NO₃^- (37,5 mg.kg^-1) was found out in treatment fertilized by urea-formaldehyde condensate. With vitamin C as well as with sugar content the best results were achieved in treatment fertilized by mixture DE+DC; and were statistically significant in comparison to other fertilizer treatments.