IRRIGATION MANAGEMENT AND FORAGE YIELD OF megathyrsus maximus CV. ZURI

ABSTRACT The objective was to evaluate the efficiency of water and energy use in intensive irrigated pasture systems, conducted under intermittent stocking, as well as their effects on the forage yield of Megathyrsus maximus cv. Zuri. The study was carried out in the municipality of Santa Teresa-ES, employing a randomized block design, composed of two treatments: irrigation management with variable depth, and irrigation without management, with a fixed depth. Irrigation management was conducted with the support of electronic spreadsheets (“Iriifes”), using the Hargreaves and Samani method to estimate reference evapotranspiration (ETo) and the water balance to determine the gross irrigation depth. The variables analyzed included dry biomass production, water volume per kilogram of biomass produced, and energy demand per kilogram of biomass. The results indicated no statistical difference (p > 0.05) in dry biomass production and plant height between the managed and unmanaged systems. The irrigation management system showed significantly higher values (p< 0.05) for energy use efficiency (3.71 kg DM·kWh⁻¹) and water use efficiency (12.43 g DM·L⁻¹) compared to the treatment without management. Although irrigation management did not increase biomass production during the evaluated period, the practice significantly increased water and energy efficiency, highlighting its importance for sustainability and the rational use of resources in intensive forage systems. Keywords: Water Efficiency. Pasture. Water Balance.