Can a blend of amendments be an important component of a rehabilitation strategy for surface coal mined soils?

Abstract

Soil compaction impedes plant growth by negatively affecting water infiltration, soil aeration, access to soil water and nutrients, and consequently restricts root development. Previous studies to alleviate such problems in rehabilitated mine soils using a single amendment material did not provide a long lasting solution. The aim of the study was to quantify the role of different amendments in alleviating selected soil hydraulic properties. Five single amendment materials and three different blends of amendments were mixed thoroughly with degraded mine soil in a 1:3 (amendment:soil) ratio and packed in columns. Two additional unamended soils with different bulk densities were included as benchmarks. In general, the application of amendments reduced bulk density (BD) by 4-20%, enhanced infiltration rate by 15-70%, increased porosity by 5-35% and increased plant available water (PAW) by 9-33% compared with the unamended soils. Between amendments, the blends of amendments reduced BD by 9-16%, enhanced infiltration rate by 17-59%, increased porosity by 6-32%, and PAW by 4-28% compared with single amendments. The study showed that a blend of amendments have better soil restoration capacity through improving porosity, infiltration rate and plant available water. A blend of amendments therefore has the potential to be a sustainable and an important component of a rehabilitation strategy for surface coal mined soils.