Effect of Salinity stress and Herban mineral fertilizer on the morphological traits of bitter olive (Melia azedarach L.)

Salinity stress is one of the most important factors limiting the growth and expansion of plants on the planet. In the world, an area of about 800 million hectares, in Iran about 44 million hectares and in Golestan province more than 75000 hectares of its lands are affected by salinity and has poor vegetation, sparse and exclusively salinity-resistant species. The use of salinity stress-resistant tree species and increasing their yield by adding the required nutrients from different sources to the soil can be effective in establishing vegetation and optimal use of saline soils.

For this purpose, the present study was performed on one-year-old bitter olive seedlings (Melia azedarach) in a factorial experiment with two-factor as a completely randomized design. Salinity stress with irrigation water once every five days in five levels including 0, 5, 10, 15 and 20ds/m and fertilization in four levels including 0, 50, 75 and 100 g of Herbban mineral fertilizer it was applied for each seedling with five replications for 120 days. In order to reduce the adverse effects of displacement and repair of damaged roots, fertilization was performed 50 days before salinity stress. During the period of salinity stress, the rate of vitality quality and survival percentage were measured every five days and at the end of the period, 15 vegetative traits were measured. Data analysis of variance was performed using SPSS software and Duncan test was used to compare the means. Rank data were also analyzed by Kruskal and Ellis tests.

The results showed that salinity stress caused a significant decrease in vitality quality, survival, longitudinal growth, leaf area, number of leaves, average individual leaf area, specific leaf area, leaf fresh weight, leaf dry weight, fresh weight Root and leaf specific gravity increased at 5% probability level. The effect of fertilization caused a significant increase in longitudinal growth and a significant decrease in leaf specific gravity. The highest vitality quality and survival were observed in conditions without salinity stress and fertilizer application. The lowest vitality quality and survival were obtained at 20ds/m and 100 g of fertilizer. Significant increase in longitudinal growth and significant decrease in leaf specific gravity were the only significant effects of fertilization. Comparison of means did not show any difference between the mentioned traits at the control level and 5ds/m. The highest survival percentage at the end of the period at the levels of 10 and 15 ds/m were equal to 100 and 75%, respectively.

Therefore, according to the results, bitter olive easily tolerates salinity of 5ds/m and if suitable fertilizers are used with short stabilization time and high absorption percentage, it can be grown in areas with salinity of 10-15ds/m acted with different goals.