EFFECTS OF VERMICOMPOST APPLICATION ON SOIL AGGREGATION AND CERTAIN PHYSICAL PROPERTIES

Application of organic waste on agricultural land as a soil conditioner and fertilizing material has lately gained much attention. This study was conducted to determine the effects of vermicompost applications (0.5%, 1%, 2% and 4% w/w) on physical characteristics of soils with different textures (sandy loam, loam and clay), under laboratory conditions. The results indicated that in the higher soil aggregate fraction (>12.7 mm) aggregate fraction was limited at the three soils. Vermicompost applications in all three soils significantly increased organic matter content. When compared with control, the increasing rates in organic matter content were 14.0%, 23.8%, 42.0% and 90.2% for 0.5%, 1%, 2% and 4% vermicompost application doses, respectively. Vermicompost applications increased the wet aggregate stability and decreased the dispersion ratio of all the experimental soils in all aggregate size fractions. Overall, wet aggregate stability increased from 26.9% to 52.2% with the application rate of 4%. Correlation coefficient between organic matter content and wet aggregate stability was found as 0.918**. The lowest mean bulk density and the highest mean total porosity occurred when the most vermicompost was added. In all the soils studied, the highest permeability coefficients were gained with the application dose of 2%. As a result of increase in wet aggregate stability and decrease in bulk density, air permeability increased, and penetration resistance decreased significantly. The results obtained in this study have clearly indicated that the vermicompost application is an effective way to improve soil physical characteristics. Copyright (C) 2015 John Wiley & Sons, Ltd.