THE EFFECTS OF ORGANIC FERTILIZERS ON PERFORMANCE OF 'TOPAZ' APPLE IN ORGANIC GROWING SYSTEMS

The trial was conducted over two years in a ‘Topaz’/M9 orchard (4000 trees/ha) using a randomized block design comprised of five fertilization treatments: 400 kg/ha Compo Guano (11% N), 880 kg/ha Maltaflor Special (5% N), 880 kg/ha Agrovit (5% N), 550 kg/ha Biosol (8% N) and an unfertilized control, and two types of orchard floor management: tree row clean-cultivated and grass within the tree row mowed. The treatments began in the third year after orchard establishment. Trunk cross sectional area (TCSA), the number of flower clusters per tree, fruit set, yield and average fruit weight were determined. The tree growth (TCSA increment) was significantly higher following treatments with Maltaflor Special and Agrovit than with Biosol. The cumulative yield per tree was higher following application of Agrovit than Biosol or Maltaflor Special, but no treatments significantly increased cumulative yield compared with the control. No significant differences were found for growth, yield and external fruit quality parameters for the other fertilizers and vegetation management methods, compared with the control.