@article{fdi:010070069,
  title = {{A} simple and alternative approach based on reference evapotranspiration and leaf area index for estimating tree transpiration in semi-arid regions},
  author = {{A}yyoub, {A}. and {E}r-{R}aki, {S}. and {K}habba, {S}. and {M}erlin, {O}livier and {E}zzahar, {J}. and {R}odriguez, {J}. {C}. and {B}ahlaoui, {A}. and {C}hehbouni, {A}bdelghani},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he present work aims to develop a simple approach relating normalized daily sap flow (liters per unit of leaf area) and daily reference evapotranspiration ({ET}0) (mm/day). {T}wo methods ({FAO}-{P}enman-{M}onteith ({FAO}-{PM}) and {H}argreaves-{S}amani ({HARG})) of the calculation of {ET} were tested in order to examine their impact on the established relationships. {T}he data sets used for developing this approach are taken over well irrigated orchards from three experimental sites (olive trees, cv. "{O}lea europaea {L}.", olive trees, cv. "{A}rbequino" and citrus trees cv. "{C}lementine {A}fourar") conducted in the {T}ensift region around {M}arrakech (center of {M}orocco) and one experimental site (pecan orchard, cv. "{C}arya illinoinensis, {W}angenh. {K}. {K}och") conducted in the {Y}aqui {V}alley, northwest of {M}exico). {T}he results showed that the normalized daily sap flow was linearly correlated with {ET}0 (mm per day) calculated by {FAO}-{PM} method. {T}he coefficient of determination ({R}-2) and the slope of this linear regression varied between 0.71 and 0.97 and between 0.30 and 0.35, respectively, depending on the type of orchards. {F}or {HARG} method, the relationship between both terms is also linear but with more discrepancy ({R}-2 = 0.7). {T}his was somehow expected since this method is known to underestimate {ET}0 values in the semi-arid areas. {A}fterward, the validation of the developed linear relationship was performed over an olive orchard ("{O}lea europaea {L}.") where the measurements of sap flow were available for another cropping season (2004). {T}he scatter plot between the normalized measured and estimated sap flow based on {FAO}-{PM} method reveals a very good agreement (slope =1, and {RMSE}= 0.14{L}/m(2) leaf area). {H}owever, for the estimation of normalized sap flow based on {HARG} method, the correlation is relatively more scattered (slope = 0.95, and {RMSE}= 0.35 {L}/m(2) leaf area). {A} further validation was performed using the measurements of evapotranspiration ({ET}) by eddy correlation system and the results showed that the correlation between normalized measured {ET} and estimated normalized sap flow is best when using {FAO}-{PM} method ({RMSE}= 0.33 {L}/m(2) leaf area) for estimating {ET}0 than when using {HARG} method ({RMSE}= 0.51 {L}/m(2) leaf area). {F}inally, the performance of the developed approach was compared to the traditional dual crop coefficient scheme for estimating plant transpiration. {C}ross-comparison of these two approaches with the measurements data gave satisfactory results with an average value of {RMSE} equal to about 0.37 mm/day for both approaches.},
  keywords = {{S}ap flow ; {R}eference evapotranspiration ; {T}ranspiration ; {L}eaf area index ; {T}ree orchards ; {S}emi-arid ; {MAROC} ; {MEXIQUE} ; {ZONE} {SEMIARIDE}},
  booktitle = {},
  journal = {{A}gricultural {W}ater {M}anagement},
  volume = {188},
  numero = {},
  pages = {61--68},
  ISSN = {0378-3774},
  year = {2017},
  DOI = {10.1016/j.agwat.2017.04.005},
  URL = {https://www.documentation.ird.fr/hor/fdi:010070069},
}