@article{PAR00008841,
  title = {{L}and degradation impact on soil carbon losses through water erosion and {CO}2 emissions},
  author = {{M}c{H}unu, {C}. and {C}haplot, {V}incent},
  editor = {},
  language = {{ENG}},
  abstract = {{W}orldwide concerns with global change and its effects on our future environment require an improved understanding of the impact of land cover changes on the global {C} cycle. {O}vergrazing causes a reduction in plant cover with accepted consequences on soil infiltration and soil erosion, yet the impact on the loss of soil organic carbon ({SOC}) and its associated processes remain unaccounted for. {I}n this study performed in {S}outh {A}frica, our main objective was to evaluate the impact of plant cover reduction on (i) {SOC} erosion by water in both particulate ({POC}) and dissolved ({DOC}) forms, and (ii) soil {CO}2 emissions to the atmosphere. {T}he study performed under sandy-loam {A}crisols investigated three proportions of soil surface coverage by plants ({C}ov), from 100% ({C}ov100) for the "non-degraded" treatment to 25-50% ({C}ov50) and 0-5% ({C}ov5). {POC} and {DOC} losses were evaluated using an artificial rainfall of 30 mm h(-1) applied for a period of 30 min on bounded 1 x 1 m(2) microplots (n = 3 per treatment). {CO}2 emissions from undisturbed soil samples (n = 9) were evaluated continuously at the laboratory over a 6-month period. {A}t the "non-degraded" treatment of {C}ov100, plant-{C} inputs to the soil profile were 1950 +/- 180 g{C} m(-2) y(-1) and {SOC} stocks in the 0-0.02 m layer were 300.6 +/- 16.2 g{C} m(-2). {W}hile soil-{C} inputs by plants significantly ({P}<0.05 level) decreased by 38.5 +/- 3.5% at {C}ov50 and by 75.4 +/- 6.9% at {C}ov5, {SOC}, the losses by water erosion of 0.75 g{C} m(-2) at {C}ov100 increased from 66% at {C}ov50 (i.e. 3.76 +/- 1.8 g{C} m(-2)) to a staggering 213% at {C}ov5 (i.e. 7.08 +/- 2.9 g{C} m(-2)). {T}hese losses were for the most part in particulate form (from 88.0% for {C}ov100 to 98.7% for {C}ov5). {P}lant cover reduction significantly decreased both the cumulative {C}-{CO}2 emissions (by 68% at {C}ov50 and 69% at {C}ov5) and the mineralization rate of the soil organic matter (from 0.039 g{C}-{CO}2 g{C}(-1) at {C}ov100 to 0.031 g{C}-{CO}2 g{C}(-1) at {C}ov5). {T}hese results are expected to increase our understanding of the impact of land degradation on the global {C} cycle. {F}urther in-situ research studies, however, need to investigate whether or not grassland degradation induces net {C}-emissions to the atmosphere.},
  keywords = {{S}outh {A}frica ; {G}lobal {C} {C}ycle ; {W}ater erosion ; {L}and use change ; {P}articulate and dissolved {SOC} forms},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {177},
  numero = {},
  pages = {72--79},
  ISSN = {0016-7061},
  year = {2012},
  DOI = {10.1016/j.geoderma.2012.01.038},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00008841},
}