EFFECTS OF DIFFERENT CHEMICAL FERTILIZERS ON THE YIELD AND QUALITY OF SOME STRAWBERRY CULTIVARS GROWN IN A GLASSHOUSE

This study was designed to determine the effects of different chemical fertilizers on the yield and quality of some strawberry cultivars such as Douglas, Chandler, 216 (Doritt) and Oso Grande which are popular in California, Israel and Spain. Four different chemical fertilizers including Urea, Fetrilon (13 % Fe), Sheffer (S 5-3-7) and Bayfolon (enriched with amino acid 11-8-6) were used in different doses. Experiment was designed as 4 replicates. Fertilizers were administered 0.5-1 gram pure nitrogen per plant during growing season from January to early May, twice a week. Totally 40 applications were made. Pure nitrogen necessary for every application was calculated according to the fertilizers and doses and given from the soil. Honey and bumble bees alone and together were used for pollination. Phenological observations and pomological analyses were done according to the cultivars, fertilizers and doses. The highest yield was obtained from Douglas and it was followed by Oso Grande. Although all the fertilizers and their doses have given satisfactory results in yield/plant depending on cultivars, due to the economical reasons urea is recommended. Better shaped fruits were obtained in cultivars pollinated with both bumble and honey bees.