@article{fdi:010054263,
  title = {{R}unoff generation fostered by physical and biological crusts in semi-arid sandy soils},
  author = {{M}alam {I}ssa, {O}umarou and {V}alentin, {C}hristian and {R}ajot, {J}ean-{L}ouis and {C}erdan, {O}. and {D}esprats, {J}.{F}. and {B}ouchet, {T}.},
  editor = {},
  language = {{ENG}},
  abstract = {{B}iological soil crusts occur extensively in semi-arid regions. {I}n the western part of {N}iger, they are associated with various types of physical soil crusts in fallows and in the "tiger bush ecosystem" (a landscape with a typical banded pattern consisting of densely vegetated bands of small trees and shrubs alternating with bare soil bands). {D}espite their widespread occurrence, not much research has been done regarding their role on runoff generation in the {S}ahelian environment. {T}he present study aims at: (i) highlighting the relative contribution of biological soil crusts in infiltration and runoff on crusted soil in respect with other soil factors; (ii) assessing the impact of underlying physical crusts associated with a wide range of microbial cover; and (iii) gathering the data required for an evaluation of the potential of microbial cover in water redistribution in an arid environment and for modelling purposes. {T}he study was based on runoff measurements performed in situ at the level of ten plots, 1 m(2) each, under two simulated rain-falls. {T}hose experiments were coupled with the visual characterization and image analysis of soil surface conditions as well as micromorphological examinations, using a light microscope, both on the field and at the laboratory. {V}isual estimation of crust cover was found consistent with the estimation based on the image analysis. {B}iological soil crusts capped the summit of pre-existing physical soil crusts, i.e. structural crusts, formed in situ by the impact of water drop and erosion crusts, resulting from water or wind erosion of structural crusts. {T}he percentage of microbial cover in the 1-m(2) plots range from 39 to 80% (55% in average) on structural crusts compared to 4 to 29% (17% in average) on erosion crusts. {R}unoff coefficient varied with both the level of microbial cover and the type of physical soil crust. {H}igher runoff coefficients were found where biological soil crusts had developed on erosion crusts as compared to structural crusts. {R}unoff coefficients recorded from erosion crusts increased with the level of microbial cover while negative correlations were found on structural crusts. {T}hey show that the clogging effect of microbial cover for the plasmic layer of erosion crusts is higher than that of the sand layer of structural crusts. {S}eparating biological soil crusts according to the types of the underlying physical crusts explain, therefore, the contradictory findings related to their role on infiltration and runoff generation. {T}hose data will help to evaluate the potential role of biological soil crusts in the modelling of water redistribution in the arid environment of the western part of {N}iger.},
  keywords = {{S}tructural crusts ; {E}rosion crusts ; {C}yanobacteria ; {S}imulated rainfall ; {S}ahel ; {N}iger ; {NIGER} ; {ZONE} {SAHELIENNE}},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {167-68},
  numero = {},
  pages = {22--29},
  ISSN = {0016-7061},
  year = {2011},
  DOI = {10.1016/j.geoderma.2011.09.013},
  URL = {https://www.documentation.ird.fr/hor/fdi:010054263},
}