Tifton 85 grass performance following chemical and organic fertilizers

The Tifton 85 grass offers high yield and nutritional value. It is demanding in soil fertility and highly responsive to fertilization. However, the response to fertilization can be affected by the source, dose, and installment of fertilizers, as well as environmental conditions. Evaluations of the joint application of chemical and organic fertilizers are scarce. Therefore, this study aimed to evaluate the effect of chemical and organic fertilization on agronomic characteristics, mineral use efficiencies, and bromatological composition of Tifton 85 grass, and determine fertilization strategies to optimize the yield and nutritional value of Tifton 85 grass. The findings were influenced by grass cuttings. The highest values for height and accumulated dry matter productivity were obtained with the highest fertilizer doses. The leaf/stem ratio was not affected by fertilization. The highest mineral use efficiencies were obtained with 200 and 400 kg of N/ha/year of NPK 20-00-20 formulation and up to 10 t/ha/year of poultry litter (PL), and these values decreased when applying high PL doses. The crude protein content increased, while the contents of neutral detergent fiber and acid detergent fiber decreased. The protein fractions and in vitro dry matter digestibility were not affected by fertilization. The potassium content increased with high fertilizer doses. Applying 350 to 400 kg of N/ha/year of NPK 20-00-20 formulation and 25 to 30 t/ha/year of PL promoted the highest accumulated dry matter productivity. Applying 200 to 400 kg of N/ha/year of NPK 20-00-20 formulation and 10/ha/year of PL is recommended for optimizing mineral use efficiencies. As for bromatological composition, increasing the doses of both fertilizers was beneficial in reducing fiber contents, but only organic fertilization increased crude protein content.