Rozalia Kadar

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.

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.

The flag leaf can be an important vehicle for high grain yield due to its position and photosynthetic characteristics. To identify the most adaptive and stable yielding genotype, three winter wheat genotypes were studied during two experimental years under field conditions to quantify the influence of flag leaf removal in different phenological stages on the grain yield and grain quality. To quantify the influence of the flag leaf on the main yield components, the flag leaf was removed every 7 days, starting from the booting stage to ripening. Chlorophyll a, chlorophyll b, and carotenoids were determined from the removed leaves. As a complex trait, the number of grains/spikes and the weight of the grains/spikes were highly influenced by the flag leaf removal during the early generative stages, causing a yield loss from 9% to more than 40%, depending on the variety. It was established that the photosynthetic pigments were highly influenced by the plant phenology stages and the environmental conditions, especially carotenoids, which act as photoprotective and antioxidant agents under stress conditions. Regarding grain quality, flag leaf removal had a significant influence on the accumulation of grain protein and the wet gluten content, the variability of these quantitative traits being also influenced by the climatic conditions.

The main objective of this paper is to evaluate the yield potential of 25 different varieties of oat as a reaction to seeding distance and fertilization for improvement of crop technology and identification of the most adapted varieties. Based ANOVA test, the main influence on yield is due to climate, followed by the amount of fertilizers. The sowing distance reveals its influence when combined with the fertilization, this aspect pointing out the differences between studied varieties. The triple interactions gradually reduce the influence of the factors, their combination being very significant in the case year X sowing distance X variety. The spatial comparative analysis of the three experimental years presents an overlap in the median area of the PCA ordering of the 12.5 cm sowing distance, fertilized with N₅₀P₅₀ with the 25 cm sowing distance fertilized with N₁₀₀P₅₀. There are differences between the oat varieties regarding the reaction to the nitrogen fertilization, highlighting especially the Mureşana variety where comparable yields are obtained on both levels of fertilization: 5.18 t ha⁻¹ (N₅₀P₅₀) and 5.59 t ha⁻¹ (N₁₀₀P₅₀).

Nitrogen fertilization is indispensable in increasing wheat crop productivity but, in order to achieve maximum profitable production and minimum negative environmental impact, improving nitrogen use efficiency (NUE) should be considered. The aim of this study was to evaluate the nitrogen use efficiency (NUE) in a long-term wheat–maize–soybean rotation system with the final purpose of increasing the overall performance of the wheat cropping system. Research was undertaken at the Agricultural Research Development Station Turda (ARDS Turda), located in Western Transylvania Plain, Romania. The experimental field was carried out at a fixed place during seven wheat vegetation seasons. The plant material consisted of a wheat variety created by the ARDS Turda (Andrada), one variety of maize (Turda 332) and one variety of soybean (Felix). The experiment covered two planting patterns: wheat after maize and wheat after soybean and five levels of nitrogen fertilization (control-unfertilized, fertilization with 0—control plot, 30, 60, 90 and 120 kg N ha⁻¹ y⁻¹). The following indices were assessed: NUE (nitrogen use efficiency), N uptake and PFP (partial factor productivity). The results of the present study suggest that reduced N-fertilization doses could improve N uptake and utilization for both planting patterns.