Bermudagrass “Tifton 85” sazonality production during the year with and non-irrigated up different doses nitrogenadas in southern of Brazil

Studies have shown that well-managed pastures can reach high productivity. In this sense, tropical forages, such as Bermudagrass, have demonstrated high productive aptitude with the increasing lineares increases throught frequent and fractionated nitrogen-based fertilization. In addition, integrated with water management management through irrigation, it contributes to reaching the productive peak of pastures in regions with tropical and subtropical climates. Thus, high productive capacities have the potencial to add greater profitability per area and reduce pressure on new exploraty areas. Fot this purpose, the experiment carried out on a diary farm for two years, evaluated the yield and nutritional value of irrigated and non-irrigated Tifton 85 under different nitrogen doses. The statistical analysis was performed following a 2×2×4×4 factorial scheme, with four replications. Treatments consisted of (i) two growing years, (ii) irrigation, (iii) four seasons (spring, summer, fall, and winter), and (iv) four nitrogen doses (0, 20, 40, and 60 kg ha −1 cycle −1 ). The evaluated parameters consisted of total forage yield (TFY) and the bromatological components crude protein (CP, %), neutral detergent fiber (NDF, %), and acid detergent fiber (ADF, %). Productive seasonality is a concern for ranchers, as it increases the risk of lack of food for the animal. The use of irrigation and nitrogen fertilization increased TFY, which was higher in the summer, decreasing gradually in direction the cool seasons that influenced production. With regard to TFY, it was possible to observe the seasonality during the seasons of the year, spring and summer (warm season) concentrated 65% of forage production, with a ratio of 50% of production in the Cool season (autumn/winter). However, irrigation reduced the productive seasonality by 58% in the cool season period. The use of nitrogen allowed big increasing linear in TFY depending on the doses applied, reaching the increases between 5 and 8 Mg ha −1 for each treatment doses. The highest TFY value (38.5 Mg ha −1 year −1 ) was observed with irrigation and the highest nitrogen dose. Significant effects were observed for NDF and CP. The use of irrigation also allowed increases of 1% in CP, providing a higher quality forage. CP presented linear increments as a function of irrigation × nitrogen doses.