Linkages between biocrust development and water erosion and implications for erosion model implementation

Liqian Gao, Matthew A. Bowker, Hui Sun, Jun Zhao, Yunge Zhao

Research output: Contribution to journalArticle

Abstract

Biological soil crusts (biocrusts) are an important factor influencing water erosion on slopes, but they are not represented sufficiently in erosion models, which limits the reliability and accuracy of these models. Determining the predictor that can represent the effects of biocrusts on water erosion and the relationship between this predictor and water erosion is the key to solving this problem. Accordingly, we sampled 20 undisturbed biocrust samples from 10 slopes in the Loess Plateau region of China, representing a developmental sequence and used rainfall simulation to explore the effects of biocrust development on soil loss under water erosion. The results showed that the moss percentage cover was a better predictor than cyanobacterial or moss biomass to predict the resistance of biocrust covered soil to water erosion. As expected, there was a strong negative relationship between sediment concentration and moss cover. Effect of biocrust development on water erosion can be divided into two stages, based on a threshold moss cover of 35% beyond which water erosion was completely prevented. Where moss cover was below 35%, sediment concentration decreased logarithmically along with the increase of moss coverage. Biocrusts controlled water erosion through two tightly correlated mechanisms, decreasing erodibility (the K factor) and enhancing cover of the soil surface (the C factor). Increasing moss cover appears to induce a cascade of changes in soil organic matter, texture and organic carbon. All of these factors jointly control water erosion. Accounting for the effect of biocrusts in the Revised Universal Soil Loss Equation is essential, and we recommend that the most practical way of doing so is to ensure that the effect of biocrust cover, particularly moss cover, is more effectively and consistently taken into account when estimating the C factor. The results of this study will provide a scientific basis for the selection of parameters considering the biocrust effects in soil erosion models.

Original languageEnglish (US)
Article number113973
JournalGeoderma
Volume357
DOIs
StatePublished - Jan 1 2020

Fingerprint

soil erosion models
soil crusts
soil crust
water erosion
moss
mosses and liverworts
erosion
Revised Universal Soil Loss Equation
soil
sediments
erodibility
biological resistance
rainfall simulation
loess
sediment
soil erosion
soil organic matter
effect
plateaus
soil surface

Keywords

  • Biomass
  • Coverage
  • Cyanobacteria
  • Loess Plateau
  • Moss
  • Threshold

ASJC Scopus subject areas

  • Soil Science

Cite this

Linkages between biocrust development and water erosion and implications for erosion model implementation. / Gao, Liqian; Bowker, Matthew A.; Sun, Hui; Zhao, Jun; Zhao, Yunge.

In: Geoderma, Vol. 357, 113973, 01.01.2020.

Research output: Contribution to journalArticle

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abstract = "Biological soil crusts (biocrusts) are an important factor influencing water erosion on slopes, but they are not represented sufficiently in erosion models, which limits the reliability and accuracy of these models. Determining the predictor that can represent the effects of biocrusts on water erosion and the relationship between this predictor and water erosion is the key to solving this problem. Accordingly, we sampled 20 undisturbed biocrust samples from 10 slopes in the Loess Plateau region of China, representing a developmental sequence and used rainfall simulation to explore the effects of biocrust development on soil loss under water erosion. The results showed that the moss percentage cover was a better predictor than cyanobacterial or moss biomass to predict the resistance of biocrust covered soil to water erosion. As expected, there was a strong negative relationship between sediment concentration and moss cover. Effect of biocrust development on water erosion can be divided into two stages, based on a threshold moss cover of 35{\%} beyond which water erosion was completely prevented. Where moss cover was below 35{\%}, sediment concentration decreased logarithmically along with the increase of moss coverage. Biocrusts controlled water erosion through two tightly correlated mechanisms, decreasing erodibility (the K factor) and enhancing cover of the soil surface (the C factor). Increasing moss cover appears to induce a cascade of changes in soil organic matter, texture and organic carbon. All of these factors jointly control water erosion. Accounting for the effect of biocrusts in the Revised Universal Soil Loss Equation is essential, and we recommend that the most practical way of doing so is to ensure that the effect of biocrust cover, particularly moss cover, is more effectively and consistently taken into account when estimating the C factor. The results of this study will provide a scientific basis for the selection of parameters considering the biocrust effects in soil erosion models.",
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