Influence of Nitrogen and Phosphorus Fertilization on Wheat Yield Under Rainfed Conditions at S.C.D.A. Șimnic-Craiova

This study evaluated the effect of nitrogen and phosphorus fertilization on wheat grain yield under rainfed conditions at S.C.D.A. Șimnic-Craiova during 2022-2026.The experiment was conducted as a two-factor 5 × 5 design with two replications and 25 fertilizer combinations. Phosphorus was applied at rates of 0-160 kg P2O5 ha-1 , while nitrogen rates ranged from 0 to160 kg N ha-1 . Mean grain yield increased from 1.81 t ha-1 in the unfertilized control (P0N0) to 6.87 t ha-1 at P160N120. Both phosphorus and nitrogen had highly significant effects on wheat yield. However, the interaction between the two nutrients was not statistically significant. Nitrogen application increased yield from 3.26 t ha-1 at N0 to 5.92 t ha-1 at N160. The small andnon-significant difference between N120 and N160 indicated a yield plateau at higher nitrogen doses. Although P160N120 produced the highest numerical yield, it did not differ significantly from P160N160.The results confirm the importance of balanced N and P fertilization, while showing that yield alone cannot establish the economic optimum fertilizer dose.