The Effect of Humic and Fulvic Acids as Bio-Fertilizers on the Growth of Pistacia vera Seedlings under Alkaline Conditions

Introduction: Pistachio (Pistacia vera), as an important agricultural product, normally faces different problems in Iran. Alkalinity is one of the main factors that has detrimental effects on pistachio growth and its production by reducing availability and solubility of essential elements. Using some fertilizers and chelating agents improves the availability and solubility of nutritional elements in the rhizosphere and thereby improves the growth ofplants. Materials and Methods: The current research investigated the effect of two bio-fertilizers (humic and fulvic acids) on the growth of pistachio seedlings grown in semi-hydroponic cultures containing either Fe-EDDHA or FeSO4. The pH of culture mediums was adjusted to 6.5, 7.5 and 8.5. Results: The results indicated that using humic substances (humic and fulvic acids) can increase pistachio dry weight under alkalinity conditions. These findings were remarkable, especially in the presence of Fe-EDDHA versus FeSO4. Conclusion: Humic substances (as bio-stimulants), especially in the presence of EDDHA, can reduce or compensate some detrimental effects of alkalinity and thereby improve plant growth.