The Effect of vermicompost on salt tolerance of bean seedlings (Phaseolus vulgaris L.)

In the recent years, increasing production of waste as a result of population growth, increased food consumption, industrial development and urbanization growth, is regarded as a serious challenge. Vermicompost, as an end product of urban waste recycling with proper physicochemical features, can play an effective role in plant growth and development and also in reducing harmful effects of various environmental stresses on plants. For this purpose, a study with the aim of investigating the effects of vermicompost and salinity interactions on morphological traits of bean (Phaseolus vulgaris L. cv. Light Red Kidney) seedlings was performed. The experiment was conducted based on a randomized complete block design, including five different volumetric ratios of vermicompost and sand (0:100; 10:90; 25:75; 50:50 and 75:25), and four levels of salinity (30, 60, 90 and 120 mmol l-1 NaCl), equal to 2.75, 5.50, 8.25 and 11 deciSiemens per meter (dS/m) respectively, along with control (0.00), in three replications. Seeds were cultured in plastic pots and sampling of seedlings was done after 28 days. The results showed that in an environment without stress, vermicompost had significant effect (p ≤ 0.05) on the stem length, internodes number, area and dry weight of leaves, diameter, dry weight and total roots length, while having no significant effect on stem dry weight. The interaction between salinity and vermicompost has significant effect on the stem length, internodes number, the area and dry weight of leaves and dry weight of roots but no significant effect was observed on the stem dry weight, diameter and total roots length. Thus, in the low levels of salinity, all ratios of vermicompost and in high levels of salinity, high ratios of vermicompost can limit the negative effects of salinity on bean seedlings.