Effect of Vermicompost Supplemented by Foliar Application of Silicate on Marjoram Plants Grown in Saline Soil

Abstract

This study aimed to reduce the negative effects of soil salinity on marjoram plants by adding vermicompost to the saline soil complemented by foliar application of silicate (Si +2 ) to their leaves. To achieve this purpose in field, the experiment was arranged as a factorial experiment. (Two way) Based on randomized complete block design with four replications. The first factor was vermicompost which was added at four rates (0, 3, 4 and 5 ton fed -1 ). The second factor was silicon which was used at four rates (0, 2.5, 3.75 and 5 mM). Results revealed that the single application of either vermicompost or silicon reduced Na and proline concentration in plant shoot and enhanced plant growth, nutrient content, carbohydrate percentage and essential oil yield in plant shoots. This increase remained constant and not correlated with the rates of application. The combined application of vermicompost and foliar spraying of silicon resulted in noticeable increase in plant growth, nutrient content (N, P, K and Ca), carbohydrate percentage and essential oil yield in marjoram plants; the highest values of all parameters were recorded by using vermicompost at rate 3 or 4-ton fed -1 coupled with spraying 3.75 mM of silicon solution on plant leaves. These results proved that amendment of saline soil by adding vermicompost and spraying silicon solution on plant leaves directly is a good strategy for the reclamation of saline soil and mitigation of salt stress within plant tissues.