Technological and climatic factors significantly influence the expression of quality and quantity properties of spring wheat. This study aims to quantify the effects of weather conditions and fertilizer systems on spring wheat yield, quality (protein content), and physiological indicators (leaf vapor pressure deficit, evapotranspiration, surface temperature of the flag leaf) and to identify a suitable spring wheat genotype for the Transylvanian Plain. The experimental factors were: Y represents the year (Y₁, 2019; Y₂, 2020); F represents the fertilizer variant (F₁, a single rate of fertilization: 36 kg ha⁻¹ of nitrogen; F₂, two rates of fertilization: 36 kg ha⁻¹ of nitrogen + 72 kg ha⁻¹ of nitrogen; F₃, two rates of fertilization: 36 kg ha⁻¹ of nitrogen + 105 kg ha⁻¹ of nitrogen); and S represents the genotype (S1, Pădureni; S2, Granny; S3, Triso; S4, Taisa; S5, Ciprian; and S6, Lennox). This multifactorial experiment with three factors was conducted on Phaeozem soil. Regardless of weather conditions, fertilization with N_100–110 at the head swollen sheath (stage 10, Feeks Growth Scale for Wheat) is deemed the most suitable variant because it yields an average grain yield of 5000 kg ha⁻¹ of good quality (13.84% protein) with a considerable flag leaf area (29 cm²) where physiological processes can optimally support the well-being of the spring wheat plants. Beyond this level of fertilization, the average grain yield tends to plateau, but the protein content considerably increases by 13–23%, depending on the genotype. High yields were achieved in the Lennox and Triso genotypes.

Agronomic systems that can guarantee consistent and sufficient crop yields must be developed and implemented in order to address the problems presented by climate change, especially the increase in average annual temperatures and the unequal distribution of precipitation. Over the course of five successive growing seasons (2019–2024), a Poly-Factorial field experiment was carried out at the Agricultural Research and Development Station (ARDS) Turda, Romania, which is situated in the hilly region of the Transylvanian Plain. The study investigated the combined effects of soil tillage system (conventional tillage—CS; no-tillage—NT) and fertilization strategies (N₄₈P₄₈K₄₈ at sowing vs. N₄₈P₄₈K₄₈ at sowing + N₄₀.₅CaO₁₀.₅MgO₇ applied in early spring at the growth resumption) on the quantitative and qualitative performance of winter wheat (Triticum aestivum L.). Results showed a modest yield difference of 206 kg ha⁻¹ between the two tillage systems, favoring conventional tillage. However, the application of additional early-spring fertilization resulted in a significant average yield increase of 338 kg ha⁻¹. Yield variability across the five years ranged from 262 to 1797 kg ha⁻¹, highlighting the strong influence of climatic conditions on crop performance and emphasizing the need for adaptive management practices under changing environmental conditions.

This study examined the impact of nitrogen applied at booting stage on grain yield, protein content, grain N uptake, and nitrogen recovery efficiency (NRE) of common winter wheat (Triticum aestivum L.) in Transylvanian Plain, in the period 2019-2026. The experiment included eight consecutively years, four varieties and, two nitrogen doses: N50 and N100. In the variant of fertilization N50, 50 kg ha-1 nitrogen active substance were applied in autumn before sowing as basic fertilization and in the variant N100, other 50 kg ha-1 nitrogen were applied at the booting stage in addition to the base fertilization. Our research has shown that, compared to other wheat growth stages, applying nitrogen at the booting stage (one week before heading) significantly improved yield and protein content. Nitrogen applied at the booting stage conducted to an increase of yield by an average of 763 kg ha⁻¹ and in grain protein content by 2.24%. The NRE values for all the studied varieties indicate an efficient utilization of nitrogen fertilizers applied at the booting stage, except the years marked by drought in May, such as 2019/2020 or when drought from June is accompanied by scorching heat, such as 2023/2024.

This study aimed to investigate the effects of different nitrogen (N) fertilizer rates and sowing dates on grain yield, protein content, grain N uptake, and nitrogen recovery efficiency (NRE) in spring and facultative wheat (Triticum aestivum L.) cultivated in northwestern and central Romania from 2018 to 2020. The experiment was designed as a split–split plot study with two spring sowing dates (SDs): an optimal date (1–15 March) and a delayed date (postponed by two weeks). All treatments received a basal autumn fertilizer supplying 36 kg N ha⁻¹ and 92 kg P ha⁻¹. In spring, three N treatments were evaluated: no additional N (N₃₆), 72 kg N ha⁻¹ (N₁₀₈), and 105 kg N ha⁻¹ (N₁₄₁), with the supplementary N top-dressed at the booting stage. The results showed that delayed sowing significantly altered grain N uptake dynamics and reduced NRE, even under standard fertilization regimes. Specifically, delayed sowing reduced grain yield by 7.52% to 28.39% compared to optimal sowing, while adverse climatic interactions in delayed setups reduced the mean NRE to as low as 16.43%. These findings indicate that conventional N application strategies may be suboptimal under variable sowing conditions and highlight the importance of adaptive N management to improve both agronomic performance and environmental sustainability.

Depending on soil nitrogen availability and soil–climatic conditions, nitrogen application at the boot stage in wheat can help maintain the photosynthetic activity of the upper leaves and support grain development and filling, thereby contributing to increased yield and protein content. This study examined the impact of nitrogen applied at the booting stage on grain yield, protein content, grain N uptake, and nitrogen use efficiency (NUE) of common winter wheat (Triticum aestivum L.) in Transylvanian Plain conditions. The experiment included eight consecutive crop seasons (2018–2026), four varieties (Andrada, Codru, Luminiţa, Georgiana), and two nitrogen doses: N₅₀ and N₁₀₀. In the N_50- fertilization variant, 50 kg ha⁻¹ nitrogen active substance was applied in autumn before sowing as basic fertilization and in the variant N_100-, and other 50 kg ha⁻¹ nitrogen was applied at the booting stage in addition to the base fertilization. The results showed that the additional fertilization of 50 kg N ha⁻¹ at the booting stage, on top of the 50 kg N ha⁻¹ applied before sowing, increased grain yield by an average of 763 kg ha⁻¹ and grain protein content by 2.24 percentage points compared with the basic fertilization treatment (N₅₀). The magnitude of the response varied among growing seasons and wheat genotypes. The calculated nitrogen use efficiency values also varied across genotypes and crop season, reflecting differences in crop response under the tested fertilization treatments. Since the experiment did not compare alternative nitrogen application timings at equivalent total nitrogen rates, the results should be interpreted specifically in relation to the additional nitrogen treatment evaluated in this study.