Journal Article Research Support, Non-U.S. Gov't South Africa Triticum aestivum Zea mays climate change crop model Comparative Study DSSAT Research Support, U.S. Gov't, Non-P.H.S. Sudáfrica agent-based model agricultural utility agriculture bias cambio climático carbon conservation area costo de oportunidad crop yield downscaling empirical evapotranspiration generalized additive model land cover mechanistic modelo de cultivo opportunity cost remote sensing utilidad agricultural