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 environmentallycompatible and economically viable options to increase and/or maintain SOM content. Our study was conducted to evaluate the effectsof vermicompost (0%, 0.5%, 1%, 2%, and 4% w/w) on the consistency limits and the Proctor compaction test parameters of threetexturally different soils (sandy loam, loam, and clay) from similar climatic conditions and cropping management practices. Resultsshowed that vermicompost increased the optimum moisture content (OMC) with an associated decrease in maximum dry soil bulkdensity (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 resultsindicate that vermicompost could be applied to minimize physical degradation and compaction caused by the adverse effects of frequenttillage at higher soil moisture contents. The electrical conductivity of vermicompost used in this study was high and it requires carefuland controlled use in terms of soil salinity when applied in high doses.