Determination of xaraés grass quality submitted to irrigation water levels and nitrogen and potassium doses

Abstract

In the correct pasture management, nutritional factors such as nitrogen and potassium fertilization play an important role in the forage production and quality. The aim was to evaluate the effects of the application of water levels, nitrogen and potassium doses in the Xaraés grass in the south of the State of Tocantins. For this, Xaraés grass was cultivated in the experimental field of the Federal University of Tocantins, municipality of Gurupi, TO. We used a mixture of fertilizer, combinations of N and K2O following the 1 N: 0.8 K2O ratio. To evaluate the effect of irrigation water levels and combinations of N and K2O doses in Xaraés grass, the plant height, the crude protein content and neutral detergent fiber were determined. The greatest height observed in the grass was 61.6 cm, with the dose application of 700 kg ha-1 yr-1 of N: 0.8 K2O and a water level of 120% of the ETc. The highest protein content was 11.7%, with the highest dose application of fertilizer and absence of irrigation. The highest fiber content in neutral detergent was 64%, with the estimated amount of 385.5 kg ha-1 yr-1 of N: 0.8 K2O and a water level of 120% of ETc. The conclusion was that the plant height, fiber detergent and crude protein content were influenced by the change in water level of irrigation and fertilizer doses. The values of plant height and crude protein increased with the increase of water levels and manure dose, while the fiber content of neutral detergent decreased with the increase of irrigation and varied little with the increase of fertilizer dose.