Onion yield and yield contributing characters as affected by organic fertilizers

Two-year field study was performed with the aim to investigate the effect of organic fertilizers (fully decomposed farmyard manure and bacterial fertilizer) on yield, bulb weight and number of bulbs per plot in five onion cultivars. The applied bacterial fertilizer included Bacillus megaterium, Bacillus licheniformis, Bacillus suptilis, Azotobacter chrocoocum, Azotobacter vinelandi and Derxia sp. NPK fertilized and unfertilized plots were included in the trial as controls. Yields from unfertilized, plots treated with manure and bacterial fertilizer were 24.3%, 25.3% and 48.8% of yield measured for NPK control (100.0%), respectively. Since farmyard manure did not provide significant increase in yield, bulb weight and number of bulbs per plot in comparison to unfertilized control, its application is not recommended for onion. Bacterial fertilizer may be used for organically grown onion. However, significant differences in yield and bulb weight that have been found among the cultivars imply the importance of genotypes screening. Cultivar Zlatno gnezdo responded well to bacterial amendment and it could be recommended to organic producers and exploited in breeding programs.