These new functions improve our knowledge concerning
the relationship between water stress and citrus yield and
therefore its implications for sustainable management of
available water resources. According to the results of the
present study, the new proposed model for explaining the
combined effect of deficit irrigation in several periods
would be an additive–multiplicative model, considering
that the effect of water stress in previous stages
determines the crop yield response when DI is applied
at the various stages. Our models indicate that the crop
water production function under DI programmes would
have a quasi-linear relation for water deficits below to
40% ETC