@article{fdi:010085916,
  title = {{M}odeling sorghum-cowpea intercropping for a site in the savannah zone of {M}ali : strengths and weaknesses of the {S}tics model},
  author = {{T}raore, {A}. and {F}alconnier, {G}. {N}. and {B}a, {A}. and {S}issoko, {F}. and {S}ultan, {B}enjamin and {A}ffholder, {F}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}ntercropping is a key entry point for sustainable intensification of cropping systems in sub-{S}aharan {A}frica where variable rainfall conditions prevail. {C}rop simulation models can complement field experiments to assess the agronomic and environmental performances of intercropping systems under diverse climatic conditions, including hypothetical future climate. {S}o far, crop models that can handle intercropping, such as {STICS}, have not often been extensively evaluated for tropical conditions and for species grown by farmers in sub-{S}aharan {A}frica. {T}he objective of this study was to evaluate the performance of the calibrated {STICS} model to simulate sorghum-cowpea intercropping systems in rainfed conditions in {W}est {A}frica. {W}e used data from field experiments conducted at the {N}'{T}arla {A}gronomic {S}tation in {M}ali in 2017 and 2018. {T}wo varieties of sorghum (local and improved) with contrasting photoperiod sensitivities were grown as sole crop and intercropped with cowpea, with additive design. {T}wo sowing dates and two levels of mineral fertilization were also investigated. {M}odel simulations were evaluated with observed data for phenology, leaf area index ({LAI}), aboveground biomass, grain yield and in-season soil moisture. {L}arge variations in aboveground biomass of sorghum and cowpea was observed in the experiment (i.e. 3.5 - 9.6 t/ha for sorghum and 0.4-2.5 t/ha for cowpea), owing to the treatments (i.e. sole vs intercrop, early vs late sowing, no fertilizer input vs fertilizer input). {S}uch variations were satisfactorily reproduced by the model, with {EF} of 0.81 in calibration and 0.58 in evaluation (with relative r{RMSE} of 23 % and 43 %) across crops. {S}orghum {AGB} simulations were more accurate (r{RMSE} of 21 % and {EF} of 0.54) than cowpea {AGB} simulations (r{RMSE} of 25 % and {EF} of -0.09). {T}he two main observed features of the intercropping system were well reproduced by the model. {F}irstly, cowpea and sorghum aboveground biomass decreased with intercropping compared with sole cropping, and the decrease in cowpea biomass was greater than the decrease in sorghum biomass. {S}econdly, despite a reduction in sorghum and cowpea yield, {L}and {E}quivalent {R}atio of the intercropping for aboveground biomass was always above one. {W}ith regard to grain yield, observed {LER} was above one only in the non-fertilized treatment. {T}he model failed at reproducing this behavior, probably because of insufficiently accurate calibration of the process leading to grain yield formation: r{RMSE} for grain yield was 49 % in calibration and 41 % in evaluation. {B}ased on these findings, we discuss avenues to improve model calibration and use the model to explore options for sustainable intensification in land constrained sub-{S}aharan {A}frica.},
  keywords = {{C}ompetition ; {S}owing date ; {V}arieties ; {F}ertilization ; {A}boveground biomass ; {MALI} ; {AFRIQUE} {SUBSAHARIENNE} ; {ZONE} {TROPICALE}},
  booktitle = {},
  journal = {{F}ield {C}rops {R}esearch},
  volume = {285},
  numero = {},
  pages = {108581 [16 ]},
  ISSN = {0378-4290},
  year = {2022},
  DOI = {10.1016/j.fcr.2022.108581},
  URL = {https://www.documentation.ird.fr/hor/fdi:010085916},
}