Apr 20, 2017 · These results further indicate that the porosity of compost increased from 60.7 to 72.5% with the moisture content increasing from 25.6 to 32.1% (Fig. 5 “C”). The porosity is negatively correlated to bulk density ( R 2 = 0.93) and positively correlated to moisture content of compost ( R 2 = 0.60).