الفهرس 
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Abstract
The present work aimed to study the influence of three gradual rates of nitrogenous fertilizer (ammonium nitrate; NH4NO3) and humic acid (potassium humate) at four doses and their interactions on vegetative growth and chemical constituents of Calotropis procera plant. Two pot experiments were conducted at a private farm at Tezment village – Bani Sweif Governorate during the two successive seasons of 2015 and 2016. A split-plot in randomized complete block design with three replicates. Ammonium nitrate (33% N) at the rates of (1 gm. (control), 2 and 4 gm /plant). Potassium humate at rates of (0, 4, 8 and 12 gm. /plant) were applied to the soil for three times at monthly intervals.
The obtained results showed that all morphological characteristics i.e. plant height, stem diameter, number of branches and leaves, leaf area per plant, plant fresh and dry weight, root fresh and dry weight were increased by the application of different rates of ammonium nitrate and potassium humate fertilizer or their combinations. Also treated plants with ammonium nitrate and potassium humate fertilizers showed a significant increase in chlorophyll a, b, carotenoids, total carbohydrates (%), N%- P%¬- K% and total alkaloids content of Calotropis procera leaves as compared with untreated plant. While total phenolic content and total flavonoids content were decreased with fertilization by different rates of ammonium nitrate and potassium humate.