The effect of different nitrogen and phosphorus fertilization on the herbage yield and quality of Savucak village pasture in Karakoçan district of Elazığ province

This research was conducted for two years in 2021-2022 to determine the effect of different doses of nitrogen and phosphorus fertilization on yield and quality in the Savucak village pasture of Karakoçan district of Elazığ province. The research was conducted in a randomized block trial design with three replications according to factorial order. In the trial, a total of 25 different combinations were used, combining 5 doses of nitrogen (N₀=0, N₅=5, N₁₀=10, N₁₅=15, N₂₀=20 kg N/da) and 5 doses of phosphorus (P₀=0, P₄=4, P₈=8, P₁₂=12, P₁₆=16 kg P₂O₅/da) for two years and urea (46% N)for nitrogen and TSP (44% triple super phosphate) for phosphorus were used as fertilizer sources. According to the results of the research, as the doses of nitrogen and phosphorus fertilizers increased, the green herbage yield of the pasture increased from 53,4 kg/da to 103,8 kg/da. In the pasture where nitrogen and phosphorus doses were applied, the proportion of wheatgrass in dry grass varied between 95,7-62,4%, the proportion of legumes between 1,7-19,8%, and the proportion of other family plants between 2,2-20,6%. The highest crude protein rate (22,4%) of pasture hay was obtained from the parcel where 15 kg/da nitrogen and 4 kg/da phosphorus were applied. Crude protein yield increased approximately 2,5 times, from 8,8 kg/da to 20,4 kg/da. ADF and NDF ratios increased depending on the phosphorus dose. DMD (61.7%-66.6%) ratios varied depending on fertilizer application. DMI (2,2%-2,9%) and RFV (107,7-145,1) increased continuously depending on the nitrogen fertilizer dose. Ca, Mg, K and P ratios of pasture hay were obtained as 0,97-1,39%, 0,24-0,35%, 2,18-3,19% and 0,30-0,41%, respectively and it was determined that it varies depending on the applied fertilizer doses. The increase in applied nitrogen and phosphorus doses was found to enhance green forage, dry forage, crude protein, DDM ratio, DMI ratio, RFV, Ca, Mg, K, and P yields. Additionally, it was observed that nitrogen doses reduced the ADF and NDF ratios, while phosphorus doses increased them. These results show that in pastures with similar ecological conditions, the combination of 15 kg/da N, 12 kg/da P in terms of yield, and 15 kg/da N, 4 kg/da P in terms of quality may be the optimum fertilization strategy.