EFFECT OF DIFFERENT VERMICOMPOST RATES AND POT VOLUME ON PRODUCING CELERY AND RED CABBAGE UNDER URBAN HORTICULTURE CONDITIONS

Urban horticulture has become one of the most important constitute actions to address poverty and fight against hunger, especially in the mega cities like Cairo, which suffering from limited availability of agricultural land as well as used in mitigating greenhouse gases (GHG's) and climate change mitigation and adaptation measures. The use of green roof technique via soilless culture systems and vermicomposting improve the efficiency of urban horticulture under the expected climate change conditions. The study was carried out during two successive winter seasons of 2014/2015 and 2015/2016 under green roof system condition at the Central Laboratory for Agricultural Climate, Agricultural Research Center, Egypt. The study aimed to optimize the use of local substrates (sand and rice husk) and provide vermicomposting technique for recycling the urban organic wastes through investigate different vermicompost rates (10, 20 and 30%) as a substrate amendment mixed with sand: rice husk (1:1 V/V) compared to peat moss : perlite (1:1 V/V) (control)  combined with three different volume of pots (4, 6, and 8 L) on vegetative growth, yield and quality of celery and red cabbage. Physical and chemical properties of substrates, vegetative growth, yield characteristics and N, P and K contents of celery and red cabbage were determined. The physical and chemical properties of different substrate mixtures were affected by vermicompost implement rate. The obtained results indicated that increasing pot volume from 4 to 8 L of substrate led to increase the vegetative and yield of celery and red cabbage in reverse to the economic efficiency. The medium pot volume of substrate gave the highest economic yield of celery and red cabbage compared to the other volumes. Increasing the rate of vermicompost from 10 to 20% led to increase the vegetative and yield characteristics of celery and red cabbage while increasing up to 30% had a negative impact. Increasing the vermicompost rate from 10 to 30% led to increase the N, P and K contents of celery and red cabbage compared to the control treatment while increasing the pot volume from 4 to 8 L/plant decreased N, P and K contents of celery and red cabbage. The best vegetative growth and yield of celery were given by using sand + rice husk + vermicompost (40: 40: 20 V/V) in pot volume 8 L for producing more healthy, economically and environmentally food. The economic results had a different view point, pot volume 4 L/plant combined with vermicompost rate 10% followed in ascending order by 20% and  pot volume 8 L/ plant combined with vermicompost rate 10% followed by 20% for celery and red cabbage, respectively. While the lowest economic use was given by 8 L/plant combined with peat + perlite substrate (control) in both of celery and red cabbage.