Physical-Chemical Properties of Earthworm Casts in Different Earthworm Species

Abstract

Earthworms play important role in the soil ecosystem influencing soil properties regulating underlying ecosystem functions such as soil organic matter (SOM) decomposition and soil erosion and quantifying their influence on SOM cycling in tropical ecosystems. The casts produced enhance microbial activities in soil that promote nutrient cycling and help in aggregate formation and stability in soil. The aims of this paper are to study focuses on the dynamic of physical and chemical properties of earthworm casts in different species of earthworm and aging of earthworm. The oven-dried weight of casts has been quantified in laboratory. The soil parameters pH, electrical conductivity (EC), bulk density, porosity, organic matter and exchange capacity were analyzed. The results found that pH values of casts ranged from 6.36 to 8.18. Fresh casts were characterized by higher EC, Mg²⁺, Ca²⁺, K⁺, Na⁺ and organic matter than in old cast. The values were higher in earthworm casts of Khitarae (Pheretima peguana). The moisture contents were significantly higher in fresh casts (ranged 6.89% to 33.93%). The cast of Khikhu (Pheretima sp.) bulk density values was highest (1.19 g cm³). Exchangeable K⁺, Ca²⁺, and Mg²⁺ in earthworm casts were higher than bulk soil. Porosity was highest (69.52%) in fresh casts of Khitarae (P. peguana). In conclusion, the physical-chemical properties of earthworm casts were different between the earthworm species. The distribution and biodiversity of earthworm may play and importance role in soil fertility.