Physiological and Agronomic Responses of Tamani Grass Under Different Nitrogen Fertilization Strategies

Abstract

Nitrogen is the most limiting nutrient for plant growth. Therefore, nitrogen fertilization of pastures must be prioritized to sustain high pasture yield. The objective of this study was to evaluate physiological and agronomic responses of Tamani grass managed under different nitrogen fertilization strategies. A randomized block design with four replications was used. Treatments consisted of the application of fertilizer‐controlled release (FCR) fractioned in one, two, four, or six applications per year (FCR 1×, FCR 2×, FCR 4×, or FCR 6×), conventional urea (CU), and without N fertilization (0N). The application of CU fertilizer was divided according to the number of cycles per year, considering a 21‐day cycle (rest period). The nitrogen dose corresponds to 600 kg N ha −1 year −1 . The variables photosynthetic rate and stomatal conductance showed higher rates in the FCR 6× and 4× strategies, while the variables transpiration rate, internal concentration of CO 2 , and leaf temperature were not influenced by the fertilization strategies. The highest tiller population density was observed in the CU, FCR 4×, and FCR 6×. Pastures managed with FCR 4× showed increments of 28% and 197% in total accumulated forage biomass and 27% and 209% in accumulated green forage biomass, compared to CU and 0N, respectively. The highest accumulated total forage, green forage, and green leaf blade biomass was observed in pastures managed with FCR 4× (26,733, 25,566, and 25,561 kg ha −1 year −1 , respectively). Applying FCR in four or six fractioned per year positively influenced the structural, physiological, and agronomic characteristics of Tamani grass.