@article{fdi:010088951,
  title = {{D}eterminants of the accuracy of using carbon isotopes in estimating water use efficiency of selected cereal and legume crops : a global perspective},
  author = {{M}utanda, {M}. and {C}haplot, {V}incent and {S}himelis, {H}. and {S}hamuyarira, {K}. {W}. and {F}iglan, {S}.},
  editor = {},
  language = {{ENG}},
  abstract = {{F}ield assessments of crop water use efficiency ({WUE}) are resource-consuming since they require simultaneous assessment of the total amount of water assimilated by crops for biomass and/or grain production. {A}lternative methods exist, such as estimating the carbon isotopic ratio ({C}-13/{C}-12) of the crop's leaf, aboveground biomass, or grain samples. {T}here is limited information on the determinants of the accuracy of carbon isotopes in estimating water use efficiency between crop types and environments. {T}herefore, this study aimed to evaluate the extent to which the estimation of the {C}-13/{C}-12 ratio in crop parts constitutes an accurate proxy of {WUE}, globally. {D}ata on observed {WUE} ({WUE}obs) were collated involving 518 experiments conducted worldwide on major cereals and legumes and compared with {WUE} estimates ({WUE}est) from carbon isotopes. {T}he mean {WUE}obs among all experiments was 3.4 g {L}-1 and the mean absolute error ({MAE}) was 0.5 g {L}-1 or 14.7% of {WUE}obs, corresponding to accurate predictions at p < 0.05. {H}owever, the percentage mean absolute error of observed water use efficiency (%{MAE}) estimated from grains was 3.6 +/- 11.5%, which was lower than the %{MAE} from aboveground biomass collected at harvest (3 +/- 22.8%). {I}n addition, the %{MAE} increased from 1.1 +/- 5.1% for soybean, 1.6 +/- 7.2% for maize, 1.2 +/- 8.6% for rice, 1.8 +/- 12.1% for groundnut, 2.1 +/- 14.3% for cowpea, 2.3 +/- 16.2% for bush bean, 1.8 +/- 19.9% for wheat, 2.2 +/- 21.4% for barley to 6.3 +/- 39.3% for oat, with only the latter corresponding to significant errors. {WUE}est were, in all cases, unbiased but slightly overestimated from 0.8% (maize) to 15.4% (oat). {T}he accuracy in estimating {WUE} significantly decreased with the increase in soil clay content, with sand, showing a positive correlation of 0.3 with %{MAE}, but negatively correlated with the silt content (r = -0.4). {F}urthermore, a multivariate analysis pointed out a tendency for prediction errors and bias to increase with the decrease in {WUE}obs and air temperature. {U}sing carbon isotopes for estimating crop {WUE} thus appeared reliable for all crops and world environments, provided grain samples are considered. {T}he technique tended to perform better under high {WUE} conditions, such as those generally found in maize and soybean cropping systems. {T}he identified factors that affect the accuracy of using carbon isotopes in measuring {WUE} provide valuable insights for water resource management and sustainable crop production. {T}hese findings contribute to the ongoing discourse on water conservation strategies in agriculture, offering a basis for decision-making in crop improvement programs. {I}mplementing the recommended practices from this study can potentially improve yield gains and promote resilient and sustainable agricultural systems in the changing environmental circumstances. {F}urther research should investigate the mechanisms that cause low accuracy of the isotopic technique using aboveground biomass and under arid and cool environments.},
  keywords = {carbon isotopic ratio ; cereal crops ; estimated water use efficiency ; legume crops observed water use efficiency ; {MONDE}},
  booktitle = {},
  journal = {{F}ood and {E}nergy {S}ecurity},
  volume = {13},
  numero = {1},
  pages = {e522 [19 ]},
  ISSN = {2048-3694},
  year = {2024},
  DOI = {10.1002/fes3.522},
  URL = {https://www.documentation.ird.fr/hor/fdi:010088951},
}