Water and nitrogen water use efficiency in forage palm irrigated with salt water in the Neossolo
The objectives were to analyze the water and nitrogen use efficiency by forage palm in different irrigation depths with saline water and nitrogen fertilization levels in the Brazilian semi-arid region. The experiment was conducted under field condition during one year of cultivation (360 days). The experimental design was a complete randomized block and 5 x 5 factorial scheme with five irrigation depths (125, 100, 75, and 25% of ET0) and five levels of nitrogen fertilization (0, 150, 300, 450 and 600 kg ha-1 of N) and three replicates. Irrigation and acceptable nitrogen fertilization resulted in a good water and fertilization management. Water and nitrogen use efficiency of forage palm were higher, when water depths and the nitrogen levels supplied to the soil were increased. The 125% ET0 depth showed a higher efficiency of water and nitrogen use in the forage palm during 360 days of study. In conditions of low nitrogen supply, the efficiency of nitrogen use is directly and indirectly associated with the fresh mass yield; while under high supply, the efficiency of the use of nitrogen is more effective. The use of irrigation and nitrogen fertilization in the semi-arid region is recommended to obtain higher productivity of water and nitrogen from the forage palm.