1 journal of Biological chemistry & Environmental Sciences 9(1):385-404, 2014 FULVIC ACID AND BIOFERTLIZATION AS A TOOL FOR PROMOTING GROWTH OF DATE PALM PLANTS DURING ACCLIMATIZATION STAGE Abeer, H.I.Abd-El Kareim 1 , El-Sayed, G.A.M. 2 and Afifi, M.M.I 2 1- Central Laboratory of Date Palm for Res. and Development, (ARC) Giza, Egypt. 2- Soils, Water and Environment Res. Inst. ARC, Giza, Egypt. ABSTRACT Date palm plants should be slowly acclimatized to ex vitro conditions. Soil application date palm Phoexix dactylifera cv. Malakabi plants by fulvic acid at three concentrations (20, 40 and 80 ml/l) or combined with Arbuscular mycorrhizal fungi (AMF) at 3g/pot and N 2- fixers mixed cultures (Azospirillum brasilense at 20ml/l and Bacillus polymyxa at 20ml/l) were studied. Addition of AMF once in the beginning of the experiment and addition of fulvic acid and N 2- fixers were once every 10 days in the first 6 months and once every 5 days in the second 6 months to enhance plant growth during acclimatization stage. Plants received NPK (2g/l) were used as control treatment. The results cleared that enhancing fulvic acid with AMF and N 2 fixers mixed cultures significantly increased vegetative growth (plant height, stem base diameter and total number of leaves/plant), beside increased the biological activity in the date palm rhizosphere (total counts of bacteria, fungi, actinomycetes, Mycorrhizal colonization percentage, nitrogenase and dehydrogenase activities). The studied treatments succeeded to increase the physiological parameters (chlorophyll a and b, carotene and leaf NPK content). However, decrease of soil NPK content, was determined. There was an increment in date palm plants growth by increasing the concentration of fulvic acid from 20 to 80ml/l. Pronounced treatment was achieved by using fulvic acid at 80ml/l combined with N 2 - fixers and AMF. INTRODUCION The date palm (Phoenix dactylifera L.) is one of the oldest fruit trees in the Arabian Peninsula. It has played an important role in day-to-day life of the people of this region for the last 7000 years (Ahmed et al., 1995). Date palm plants grow at a relatively slow rate in vitro and require a rather long acclimatization and growing period (ex vitro) of about 15-24 months to be