Growth Dynamics, Yield, Economic Viability and Water Use Indicators of Forage Plants Under Different Irrigation Depths

The lack of water in semi-arid areas presents challenges for agriculture, making it necessary to adopt strategies that optimise the use of this water resource. This study evaluated the effects of irrigation level on the growth, productivity, economic viability and water use indicators of different forage species in the semi-arid region of Brazil. The study was carried out in two production cycles, with a bifactorial arrangement for pasture grasses (Buffel, Aruana and BRS Kurumi) and for silage (Sorghum and BRS Capia & ccedil;u) and a unifactorial arrangement for the protein source species (Pornun & ccedil;a). Irrigation depths of 25%, 50%, 75% and 100% of the reference evapotranspiration (ETo ) were imposed. The growth rates showed linear and quadratic behaviour in the two cycles evaluated, with growth peaking at irrigation depths between 50% and 75% of the ETo. Only BRS Kurumi was influenced by irrigation depth in the first cycle. For the silage grasses, only BRS Capia & ccedil;u was influenced in the first cycle, with 100% irrigation depth standing out. In the second cycle, the 100% irrigation depth favoured the dry matter yields of BRS Capia & ccedil;u and Sorghum. Irrigation should be adjusted according to the time of year for better water utilisation.