Comparing evapotranspiration and yield performance of maize under sprinkler, superficial and subsurface drip irrigation in a semi-arid environment

In arid and semiarid environments, with shortage of water resources, maize production is competing for available water. This study analyzed the effect of different irrigation systems on maize yield, crop evapotranspiration and its components, i.e., canopy transpiration (T) and soil evaporation (E). A 2-year field experiment was conducted at the ITAP Research facilities located in Albacete (southeast Spain). Four treatments were assessed: surface drip irrigation with a spacing between drip lines of 1.5 m (SDI_1.5) and 0.75 m (SDI_0.75); subsurface drip irrigation (SubDI); solid set sprinkler irrigation (Sprink). In all treatments, irrigation was applied to refill the estimated potential water demand. Crop evapotranspiration (ETc) and E/T partitioning were estimated using a Simplified Two-Source Energy Balance (STSEB) approach. Although there was an important difference in the irrigation water applied between treatments, ranging from 743 and 722 for Sprink system to 534 and 495 for SubDI system in 2014 and 2015, respectively, yield was unaffected by the irrigation regime, resulting in an increase in the irrigation water productivity (IWP) by an average of 25% when irrigation was applied by the subsurface system. Maize ETc was affected by the irrigation system, with the SubDI achieving in 2015 a 39% reduction of seasonal ETc in comparison with the Sprink system. Similar reductions were obtained for separated E and T components with soil evaporation accounting in general for 15-20% of the total ETc. It is concluded that subsurface irrigation is a water savings strategy for irrigation of maize reducing the consumptive water use and increasing IWP. The final convenience for the widespread adoption of subsurface irrigation will depend on water availability and prices.