Effect of vesicular-arbuscular mycorrhizal fungus and humic acid application on the growth of Parkinsonia aculeata L. seedlings

The study is aimed at investigating the influence of mycorrhizal fungus and humic acid (HA) on the growthof Parkinsonia aculeata L. seedlings. The experiments were carried out during the period from July, 1st, 2017to March, 1st 2018. The inoculation with mycorrhiza was applied to the seedlings at age of 2 months. Twotypes of soils were used in this study as follows: a) a mixture of sand, peat and perlite at the ratio of 1:1:1, byvolume, and b) clayey soil. Humic acid (HA) was applied just after seed sowing at the rate of 1g/L (200 mlpots). The obtained results showed that there were significant differences between the two soil types tested.However, the seedlings grown in clayey soil displayed the highest shoot height (SH) (47.44cm), the highestshoot dry weight (SDW) (2.40g), the highest total dry weight (TDW) (3.59g) and the highest shoot/ root ratio(SRR) (2.26). The inoculation with VAM has brought about the highest SH (34.66cm), SDW (1.76g), TDW(1.76g), P% (1.81) and N% (2.73) in the leaves. However, the highest TDW was obtained in the inoculatedseedlings treated with HA acid and grown on clayey soil (4.498g). The highest P% was obtained in theinoculated seedlings of P. aculeata grown on clayey soil and untreated with HA (3.94 P%). Therefore, it isrecommended to inoculate the seedlings with VAM to achieve the highest growth and performance as animportant nursery practice in afforestation and windbreaks program and in poor soils as well.