Yield, dry matter and water productivity simulation for surface and subsurface drip-irrigated bell pepper using the SALTMED model

SALTMED model performance was evaluated by comparing simulated and observed soil water content, dry matter (DM) yield, yield and water productivity (WP) data of field-grown bell pepper (Capsicum annuum L.) under Mediterranean climatic conditions irrigated with surface and subsurface drip systems. Simulation data were obtained from field experiments performed in 2016 and 2017. Treatments were full irrigation (I100), conventional deficit irrigation at 75 and 50% actual crop evapotranspiration (ETa; I75 and I50), regulated-deficit irrigation (RDI) and partial root-zone drying (PRD) at 50% ETa using surface (SfDI) and subsurface drip systems (SbDI) on a clay-loam soil, in a split-plot with four replications. Results showed that 56 and 29 mm less irrigation water was applied to SdDI100 in 2016 and 2017, respectively, than SfDI100; RDI used 27 and 77 mm less irrigation water than SfDI100 in experimental years, respectively. SbDI and SfDI performed similarly for bell pepper yield, DM and WP. However, the effect of irrigation treatments on yield, DM and WP was significant. I100 showed the highest yield (74.9 and 71.1 t/ha in 2016 and 2017, respectively), followed by RDI in 2016; I100, RDI and I75 produced greater yield than other treatments in 2017. PRD50 and I50 produced the least yield (49.8 and 45.9 t/ha in 2016 and 2017, respectively). SbPRD50 and SbI50 had the greatest WP value under SbDI in the experimental years. Results showed that the SALTMED model simulated yield, DM, soil water content and WP reasonably well (R-2 = 0.95, 0.97, 0.98 and 0.74, respectively).

Automated summary

The performance of the SALTMED model was evaluated by comparing simulated and observed data of soil water content, dry matter yield, yield, and water productivity of bell pepper under different irrigation systems. The results showed that the SALTMED model reasonably simulated the variables of interest.