Influence of vermicompost application on soil consistency limits and soil compactibility


Abstract: Soil organic matter (SOM) is a composite indicator of soil quality. Recycling of organic wastes is one of the environmentally compatible and economically viable options to increase and/or maintain SOM content. Our study was conducted to evaluate the effects of vermicompost (0%, 0.5%, 1%, 2%, and 4% w/w) on the consistency limits and the Proctor compaction test parameters of three texturally different soils (sandy loam, loam, and clay) from similar climatic conditions and cropping management practices. Results showed that vermicompost increased the optimum moisture content (OMC) with an associated decrease in maximum dry soil bulk density (MBD). The increase in OMC at 4% vermicompost was 64.2%, 42.4%, and 33.9% for sandy loam, loam, and clay, respectively, when compared to the control. Similarly, the rate of decrease in MBD at 4% vermicompost was 8.9%, 10.9%, and 10.4% for sandy loam, loam, and clay, respectively, than that of the control. Vermicompost increased the moisture contents of both liquid (LL) and plastic (PL) limits at OMC, in which the MBD occurred. While the OMC at control was 53% of LL and 75% of PL, these values were found as 55%, 56%, 56%, and 57% of LL and as 75%, 80%, 80%, and 76% of PL for 0.5%, 1%, 2%, and 4% vermicompost rates, respectively. Our results indicate that vermicompost could be applied to minimize physical degradation and compaction caused by the adverse effects of frequent tillage at higher soil moisture contents. The electrical conductivity of vermicompost used in this study was high and it requires careful and controlled use in terms of soil salinity when applied in high doses.

Keywords: Vermicompost, Atterberg limits, Proctor compaction test, soil mechanical properties, soil friability, workability

Full Text: PDF