Earthworms: 'Soil and Ecosystem Engineers' – a Review

Abstract

Earthworms can alter the soil environment by changing soil properties. They have great potentiality to enhance soil physical properties like bulk density, infiltrability, hydraulic conductivity, porosity, aggregate stability. Due to this ability they are only species which plays significant role in pedoturbation. Similarly, their role in nutrient cycling and organic matter breakdown is of unique interest. Earthworm cast fortified with the microbial population. Increasing microbial activity in soil, increases the nutrient mineralization and release. Earthworm activity enhances root distribution so that immobile macro nutrients like phosphorous and other micronutrients, which are absorbed by plant through root interception, are easily available to the plants. Hence, earthworms play important role in bioturbation, they are considered as 'soil engineer.' However, their activity differs with the agroecosystems. Their population density is more in reduced tillage system than conventional tillage system, aerobic condition than anaerobic conditions, grasslands than forest. Low population of earthworm was found in dry land agroecosystems. But earthworm presence in extreme environment is not studied well yet. So, this paper was reviewed to explore the role of earthworm as soil and ecosystem engineer. This was already established fact but main aim of this paper is to collect the related information and conclude the future research prospects to strengthen the earthworm role as soil and ecosystem engineer.