Performance of ‘Sabiá’ Grass Irrigated with Drippers Installed in the Subsurface

Abstract

Subsurface irrigation, which provides greater water efficiency and reduces surface soil wetting, is an effective alternative for minimizing water losses through evaporation, especially under cultivation conditions that require greater resource conservation. The ‘Sabiá’ grass, an agronomically relevant forage species, may exhibit different responses when irrigated by subsurface systems. Thus, the objective of this study was to evaluate the performance of ‘Sabiá’ grass irrigated with drippers installed at different depths during different climatic seasons. The experiment was carried out from January to July 2022 under open-air conditions in Viçosa, MG, Brazil, in a completely randomized design in split plots with four replicates. The plots consisted of four cycles of ‘Sabiá’ grass, and the subplots consisted of seven depths of dripper installation (superficial, 5, 10, 15, 20, 25, and 30 cm). ‘Sabiá’ grass was cultivated in pots, and the recommendations for irrigation were based on crop evapotranspiration (ETc), which was measured in two drainage lysimeters. The water consumption and morphogenetic and agronomic characteristics of ‘Sabiá’ grass were evaluated. The total water consumption of ‘Sabiá’ grass in cycles 1, 2, 3, and 4 was 42.4, 26.7, 14.9, and 11.5, respectively. The growth, development and productivity of ‘Sabiá’ grass decreased from cycle 1 (summer) to cycle 4 (winter). Morphogenic characteristics were slightly affected by the different dripper installation depths. ‘Sabiá’ grass presented lower shoot fresh mass, shoot dry mass and water use productivity at the greatest dripper depths. ‘Sabiá’ grass presented greater root system development when the dripper was installed between 10 and 15 cm deep. The normalized difference vegetation index (NDVI) proved to be a promising tool for estimating the biomass production of ‘Sabiá’ grass. In view of these results, drip tapes should be installed between depths of 10 and 20 cm for the cultivation of ‘Sabiá’ grass in clay soil.