Dear Neeraj Pandey You used two different species for the degradation wastes but the trophic and habitat niche of both the earthworm are different.
Epigeic earthworms like (Eisenia fetida, Eudrrilus eugeniae, Eisenia andrei) feed decaying organic matter like plants leaves, decaying friuts and vegetables, paper waste etc. but endogeic species like llolobophora chlorotica, Apporectodea caliginosa, Apporectodea icterica etc. feed soil and obtain nutrients from these soil.
The habitat of both the species are also different the epigeic earthworms are like in the topsoil or upper most layer of the soil and they can not burrow while the endogeic earthworms are in the 10 to 20 inches deep soil by making horizontal burrows. so when you use the two different- different species of the earthworms to decompose the waste. Epigeic earthworms are alive in the organic waste while due too lack of the soil endogeic can not.
In this combined composting epigeic earthwormms shows hyperbolic curve and endogeic due to lack of soil die after some time.