Impacts of earthworms on soil components and dynamics. A review (original) (raw)
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Large-scale effects of earthworms on soil organic matter and nutrient dynamics
1998
A fter 30 years of unquestioned success, agriculture is now facing im-pOliant problems. In developed countries, huge increases in productivity have accompanied a severe depletion of "soil quality" in tenns of resistance to erosion, organic contents, and concentrations of heavy metals and pesticide residues. In developing countries, intensification has been less success-fuI due to socio-economicallimitations. Nonetheless, traditional practices do not conserve the quality of soils: stocks of organic matter are rapidly depleted and erosion pulls fine particles out of the surface horizons. In a context of increasing population pressure, this degradation of soils results in many social and environment problems .
A review of earthworm impact on soil function and ecosystem services
European Journal of Soil Science, 2013
Biodiversity is responsible for the provision of many ecosystem services; human well-being is based on these services, and consequently on biodiversity. In soil, earthworms represent the largest component of the animal biomass and are commonly termed ‘ecosystem engineers’. This review considers the contribution of earthworms to ecosystem services through pedogenesis, development of soil structure, water regulation, nutrient cycling, primary production, climate regulation, pollution remediation and cultural services. Although there has been much research into the role of earthworms in soil ecology, this review demonstrates substantial gaps in our knowledge related in particular to difficulties in identifying the effects of species, land use and climate. The review aims to assist people involved in all aspects of land management, including conservation, agriculture, mining or other industries, to obtain a broad knowledge of earthworms and ecosystem services.
Earthworm activities and the soil system
Biology and Fertility of Soils, 1988
nutrient resources, water and buffered climatic conditions that they need. According to the food resource they exploit and the general environmental conditions, earthworms can be grouped into different functional categories which differ essentially in morphology, size, pigmentation, distribution in the soil profile, ability to dig galleries and produce surface casts, demographic profiles and relationships with the soil microflora. Soil characteristics are both the determinant and the consequence of earthworm activities, since these animals greatly influence the functioning of the soil system. When present, they build and maintain the soil structure and take an active part in energy and nutrient cycling through the selective activation of both mineralization and humification processes. By their physical activities and resultant chemical effects, earthworms promote short and rapid cycles of nutrients and assimilable carbohydrates. Thus earthworms represent a key component in the biological strategies of nutrient cycling in soils and the structure of their communities gives a clear indication of the type of soil system that they inhabit.
EARTHWORM AS SOIL ECOSYSTEM ENGINEERS: A REVIEW
Earthworm and microorganisms are interdependent on each other. The interactions between them help to regulate the biogeochemical cycle of terrestrial life. A large diversity of fungi, bacteria, yeast, actinomycetes and protozoa are found to be present in the gut and cast of earthworms. Their number and species depend on their feed substrates obtained in soil. It has been studied that the microbial proliferation is more in the casts, due to the environment prevailing-rich nutrient supply and large surface area available for growth and reproduction of the microbes that lead to the enhanced microbial activity and humic acid contents in casts. Diversity of microorganisms is also found in vermicompost and vermiwash. This in turn depended on the raw material used for compost. A significant increase was noted in flora after composting. Within an ecological group, habitat was found to be a more important determinant of the gut wall associated community composition than the host species.
Role of Earthworms in Soil Fertility and Factors Affecting Their Population Dynamics: A Review
2015
Earthworms mix soil layers and incorporate organic matter into the soil. This mixing allows the dispersion of the organic matter through the soil and makes the nutrients held in it available to plants and improves the fertility of the soil. Earthworms when present improve the soil physical, chemical and biological properties and acts as soil conditioner. They do so by fragmentation, aeration, breakdown of organic matter in soil and release plant available nutrients and also due to secretion of plant growth hormones, their role in nitrogen fixation, carbon dynamics, and phosphorous dynamics. But their population in soil is threatened by a number of soil and environmental factors. Agricultural practices like heavy tillage operation and application of chemical fertilizers also contribute in the reduction of earthworms in soil. Change in land use due to increase in human population brings change in the system and make it unsuitable for the growth and development of earthworms. This revi...
Sustainability
Earthworms mix soil layers and bind the soil with organic matter. This combination allows organic matter to disperse through the soil and also allows plants to access the nutrients they retains and enhance the soil’s fertility. Earthworms improve the soil’s biological, chemical, and physical characteristics and serve as soil conditioners. They do so by dissolution, aeration, soil organic breakdown, the release of plant nutrients, and their role in the fastening of nitrogen due to plant growth hormone secretion. However, a variety of soil and environmental factors influence the soil population. Furthermore, it remains uncertain how soil worms modify soil microbial communities’ composition and how they impact the soil’s microbial process. By feeding on microorganisms or selecting and stimulating specific microbial groups, earthworms reduce microbes’ activity and abundance. Earthworms directly impact the plant’s growth and recycling of nutrients but are mainly mediated by indirect micr...