ABSTRACT
Field experiments were carried out on Kohlrabi (Brassica oleracea var. gongylodes) ‘Purple Vienna cv.’ at
the Experimental Farm of the Faculty of Agriculture, Moshtohor, Benha University, Egypt, during the winter
seasons of 2009 and 2010 under drip irrigation system. This study aimed to investigate the effect of organic
manure and/or mineral N-fertilizer with or without biofertilizer inoculation on growth, yield and quality of
kohlrabi knobs. Results show that using 50% mineral-N + 50% organic-N combined with biofertilizer, improved
plant growth, yield and knob quality compared to other N-fertilizer systems. Inoculation of kohlrabi transplants
with biofertilizer gave good results in this respect. Therefore, this treatment gave the best growth and increased
total yield with the best knob quality as compared with uninoculated one. The highest content of nitrate in knobs
(803.84 mg kg-1 DW) was recorded by using 100% mineral-N treatment (average in both seasons). Whereas,
adding 100% organic-N recorded the lowest content of nitrate in knobs (387.75 mg kg-1 DW) average of both
seasons. It is worthy to mention that nitrate concentration in tested kohlrabi knobs is still in the safe border for
human consumption. Finally, kohlrabi plant contains good amounts of antioxidants substances positioned to be
at the forefront of salad plants.