Effects of diatomite on soil consistency limits and soil compactibility

A number of organic and inorganic soil amendments are added to soil for improving its physical, chemical, and mechanical characteristics, which promote plant growth. Use of diatomite as a soil amendment is new and its effects on soil mechanical properties has not been studied. The Atterberg limits and the Proctor compaction test parameters are related to agronomy with regard to compaction hazard for soils and tillage. This laboratory study was aimed to assess effects of diatomite with different rates of 0%, 10%, 20%, and 30% (v/v) on soil consistency limits and soil compactibility parameters in soils with different textures. The results of this study showed that diatomite application significantly enhanced soil mechanical properties and reduced soil compactibility. Diatomite applications in all experimental soils significantly (p < 0.05) increased liquid limit (LL) and plastic limit (PL) values. The effectiveness of diatomite on LL and PL was more pronounced in soils with low clay content. As compared with the control, the highest application dose of diatomite (30%) increased LL with the rates of 43.9%, and 33.8%, in sandy loam and loamy textured soils, respectively. But, the highest LL values were obtained from 10% diatomite application in clay-textured soil. On the average, diatomite application increased PL by 12.2%, 21.5%, and 27.0% with 10%, 20%, and 30% application rates, respectively, as compared to the control. Diatomite application decreased maximum dry bulk density (MBD), but increased optimum moisture content (OMC). In all the soils studied, the lowest MBD and the highest OMC were obtained from the highest application dose of diatomite. As compared with the control, the highest diatomite application dose (30%) decreased the MBD with the rates of 10.4%, 14.0%, and 9.0%, in sandy loam, loam and clay textured soils, but it increased the OMC values with the rates of 49.1%, 42.2%, and 38.5%. The results presented in this study clearly indicated that application of diatomite lead the soils more strength to mechanical forces, since increasing the water content at OMC over LL and PL may imply that soil is more easily tilled in higher moisture contents without any deformation which also provides higher workable range.

► Diatomite applications increased liquid and plastic limit values.
► Increase in diatomite decreased the maximum dry bulk density.
► Diatomite application increased optimum moisture content.
► Diatomite increased the water content in which the maximum compaction occurred.
► Application of diatomite will cause the soil more easily tilled.