Evaluating soil degradation based on earthworm community
characteristics: A case study on loess soils
Abstract
Soil degradation restricts the development of agriculture and the degree
of soil degradation is related to land use type. Quick and efficient
evaluation of the degree of soil degradation is needed for the timeous
implementation of remedial measures to ensure soil sustainability.
Earthworm community characteristics are closely related to soil
management practices and soil quality and could be used for evaluation
purposes. In this Loess Plateau study, the degree of soil degradation
under nine different land use types (natural and planted woodland,
shrubbery, and grassland, plus cropland, orchard, and abandoned land)
was related to the earthworm community characteristics (density,
biomass, and the Shannon-Wiener, Species richness, and Pielou’s evenness
indices) using a soil degradation index calculated from soil
physicochemical properties determined for each land use type. The
earthworm community characteristics associated with a low degree of
degradation were significantly higher than those associated with a high
degradation degree. Compared to the artificially managed land use types,
earthworms in the natural ones showed higher biomass, density, and
diversity. The earthworm density, biomass, and Shannon-Weiner index were
significantly correlated with soil organic matter and total nitrogen
content. These findings indicate that earthworm community
characteristics can comprehensively characterise the physicochemical
properties and biological characteristics of soils under different land
use types. Linear correlations showed a significant relationship between
the soil degradation index and the earthworm community characteristics,
indicating that the latter could be used effectively to evaluate and
represent the degree of degradation of soils on the Loess Plateau over a
certain degradation range.