@article{fdi:010073185,
  title = {{G}rassland degradation significantly enhances soil {CO}2 emission},
  author = {{A}bdalla, {K}. and {M}utema, {M}. and {C}hivenge, {P}. and {E}verson, {C}. and {C}haplot, {V}incent},
  editor = {},
  language = {{ENG}},
  abstract = {{G}rassland degradation reduces net primary production and, subsequently, soil fertility and soil organic carbon stocks ({SOC}s); however, little is known about its impact on soil {CO}2 emissions, particularly the emissions relative to {SOC}s and biomass produced. {T}he main objective of this study, performed in {K}wa{Z}ulu-{N}atal province of {S}outh {A}frica, was to quantify the impact of grass basal cover, as main indicator of grassland degradation, on soil {CO}2 emissions. {T}he soil {CO}2 emissions were measured from three grass cover levels (non-degraded, with 100% grass cover, moderately degraded: 25 < grass cover < 50%; and highly degraded: 0 < grass cover < 5%) using a {LI}-{COR} 6400{XT}. {T}he measurements were done at three randomly selected positions in each grass cover level, from {J}anuary 2013 to {A}pril 2015. {A}t each position, measurements were done once during winter months and twice during summer months, resulting in a total of 1053 measurements for the entire study period. {T}he measured average gross soil {CO}2 emission was significantly higher (1.78 +/- 0.013 g {CO}2-{C} m(-2) day(-1)) in non-degraded than moderately (1.60 +/- 0.12 g {CO}2-{C} m(-2) day(-1)) and highly degraded grasslands (0.68 +/- 0.10 g {CO}2-{C} m(-2) day(-1)). {H}owever, when expressed relative to {SOC}s and aboveground biomass produced, the trends were opposite. {A}verage soil {CO}2 emission relative to {SOC}s was lowest in the non-degraded grassland (0.034 +/- 0.01 g {CO}2-{C} g(-1){C} day(-1)) and highest in the moderately degraded grassland (0.058 +/- 0.02 g {CO}2-{C} g(-1){C} day(-1)) with the highly degraded grassland being intermediate (0.04 +/- 0.00 g {CO}2 g(-1){C} day(-1)). {S}imilarly, soil {CO}2 emission relative to aboveground biomass produced was lowest in the non-degraded grassland at 0.15 +/- 0.02 kg {CO}2-{C} kg(-1) biomass year(-1), which was almost 5 fold lower than 0.73 +/- 0.01 kg {CO}2-{C} kg(-1) biomass year(-1) in the highly degraded grassland. {G}ross soil {CO}2 emission correlated significantly and positively with {SOC} (r = 0.83 and 0.82 for {SOC} content and stocks, respectively), {SON} (0.67 and 0.53 for content and stocks, respectively), {C}:{N} ration (0.62), and soil water content (0.75) but negatively with clay content (-0.89). {S}oil {CO}2 emission relative to {SOC}s correlated significantly and negatively with both {SOC} (-0.50 and -0.51 for content and stocks, respectively) and {SON} (-0.45 and -0.42 for content and stocks, respectively). {W}hile gross {CO}2 emissions decreased with grassland degradation, {CO}2 emission relative to both {SOC}s and aboveground biomass increased with grassland degradation. {T}hese results point to direct links between grassland degradation and global warming because {CO}2 is one of the key greenhouse gases. {T}herefore, strategies for rehabilitating degraded grasslands need to aim at reducing soil {CO}2 emission in order to mitigate climate change.},
  keywords = {{G}rassland management ; {S}oil respiration ; {C}arbon output ; {C}limate change ; {AFRIQUE} {DU} {SUD} ; {KWAZULU} {NATAL}},
  booktitle = {},
  journal = {{C}atena},
  volume = {167},
  numero = {},
  pages = {284--292},
  ISSN = {0341-8162},
  year = {2018},
  DOI = {10.1016/j.catena.2018.05.010},
  URL = {https://www.documentation.ird.fr/hor/fdi:010073185},
}