Reduction Of Urea Transformation In Soil Using Aqueous Extracted Leaves Of Neem (Azadirachta indica) And Olive (Olea europaea L)

摘要

The aim of this study was to evaluate the relative performance of two plant leaf extracts, namely neem (Azadirachta indica) and olive (Olea europaea L) in regulating nitrogen transformations, inhibiting nitrification, improving nitrogen recovery in the soil-plant systems and alleviating negative environmental impacts through two experiments. In the first one, the soil was treated with three levels of either neem or olive leaves extract (1,3 and 5 mL/100 g soil), all treatments were incubated for 40 days under controlled condition. Greenhouse (pot) experiment was the second one. Vegetable plant radish was grown for 45 days in soil fertilized with 75% or 100% of the recommended nitrogen as urea either combined or not with biofertilizer (Azotobacter chroococcoum) at a rate of 47.6 L/ ha in addition to control (not treated). In general, under incubation experiment, the level of nitrate in soil treated with leaves extracts surpassed with a different magnitude than untreated. However, there was no obvious in the inhibition rate under different leaves extracts treatment, in addition, the level of nitrification inhibition under incubation condition surpassed that of the greenhouse experiment. Results of the greenhouse experiment revealed that plant extracts minimize nitrate content in plant tissue, without a negative effect on soil biological activity. In addition, positive significant responses existed for radish weight.