Combined effect of technical, meteorological and agronomical factors on solid-set sprinkler irrigation: I. Irrigation performance and soil water recharge in alfalfa and maize

In this work, maize (Zea mays L.) and alfalfa (Medicago sativa L.) were irrigated in two adjoining plots with the same sprinkler solid-set system. Irrigation was evaluated between four sprinklers in the central position within each plot, above the canopy with pluviometers and in the soil with a FDR probe. Maize and alfalfa were simultaneously irrigated under the same operational and technical conditions during two seasons: in 2005, the solid-set irrigation system layout was rectangular, 15 m between sprinklers along the irrigation line and 15 m among lines (R15 × 15), and the seasonal irrigation applied according to the crop evapotranspiration (ETc); in 2006, the solid-set layout was R18 × 15 and the seasonal irrigation was around 30% lower than the ETc. The irrigation depth above the canopies (IDC) and the soil water recharge after irrigation (RW) were monitored using a 3 m × 3 m grid (25 points in 2005 and in 30 points in 2006). For maize, RW was assessed both in the lines of plants (CL) and between the lines (BCL).