Sand Mixing Improved Chloroform Fumigation Efficiency in the Determination of Microbial Biomass Carbon of Water-Saturated Soils

Sand mixing effects on chloroform fumigation–extraction (CFE) efficiency in the determination of soil microbial biomass carbon (MBC) of water-saturated soils were investigated in two soils with different soil organic C (SOC) contents. Sand mixing increased (P < 0.001) MBC by up to 20% and 107% for the soil with low and high SOC values, respectively, suggesting that the creation of water-empty macropores by sand mixing improved chloroform fumigation efficiency. This study demonstrates that sand mixing is a feasible measure to improve CFE efficiency for the determination of the MBC of water-saturated soils, particularly for soils with a high SOC.