## 2 Yielding as an Effect of Reduced N Fertilization
Modern agricultural techniques, such as precision farming, soil monitoring, and the use of controlled-release N fertilizers, enable the optimal utilization of this element, minimizing losses and reducing environmental impacts [21; 23; 24]. Figure 2: Relationship between nitrogen fertilizer application levels (deficient, optimal, high, excessive) and crop yields. EU proposals suggest that a reduction in N fertilization does not necessarily lead to a significant decline in crop yields, provided that fertilization is properly balanced [23]. A key component of this strategy is the better management of available resources and tailoring fertilization to the actual needs of plants. This implies a greater emphasis on precision agriculture and advanced soil analysis methods. The optimization of N fertilization allows for the more efficient use of N, even at lower application rates, which can help prevent negative effects on crop yields [19; 23]. Researchers and agronomists suggest that crops can effectively utilize lower amounts of N if fertilization is better adapted to the developmental stages of the plants and soil conditions [18]. Precise fertilizer applications in critical growth phases when the plant needs N the most can ensure that the yield potential is not compromised. In fact, such approaches may enhance soil health and reduce N losses to the environment. An important consideration is that, in many regions of Europe, excessive N fertilization is commonly practiced, with application rates often exceeding the actual needs of crops [24]. In this context, a 20% reduction in N use could benefit both the environment and farmers, lowering fertilization costs without sacrificing yield potential [22]. [PERSON] et al. [25] evidenced that reducing N application by 20% while multiple cropping with green manure application after wheat was a suitable N fertilizer management measure for improving C mitigation in arid areas without sacrificing maize yield. Similarly, [PERSON] et al. [26], as a result of field experiments conducted over four consecutive seasons (2019-2023), concluded that a 20% reduction in N application increased grain yield, grain protein content, and protein yield in respect to wheat [_Triticum aestivum_ L.). They revealed that replacing 20% of the N used in conventional farming practices with organic fertilizer represents an effective strategy [26]. Also, [PERSON] et al. [15] examined how a 20% reduction in N fertilization according to the F2F strategy is likely to impact the yields, N\({}_{2}\)O emissions, and N leaching of four intensively managed temperate grasslands in the Alpine region, two of them located in Switzerland and the other two in Germany. They noted that a 20% decrease in N fertilization would lead to a 5% drop in yields but also a 15% decline in N\({}_{2}\)O emissions and a 21% decline in N leaching, mainly as NO\({}_{3}\)\({}^{-}\)[15]. Interesting research based on biogeochemical simulation was conducted by [PERSON] et al. [27], which estimated the impact of reducing mineral N fertilization on the yields of maize, barley, rapeseed, and soft wheat in the EU. According to the simulation results, which examined reductions in N fertilizer application of 5%, 15%, and 25%, the largest relative yield reduction, compared to average yields from 2015 to 2018, occurred for soft wheat at all levels of fertilizer reduction. In contrast, for maize, even a 25% reduction in N application did not lead to a decline in yield. The importance of reducing and optimizing N fertilization was further highlighted by [PERSON] et al. [28], who conducted a three-year field experiment on pepper cultivation at the Finca La Orden experimental farm in Spain. The applied fertilization strategy, which included doses of 0, 60, 120, and 180 kg N/ha in 2020 and 2021 and 0, 100, and 300 kg N/ha in 2022, demonstrated that N applications above 120 kg N/ha did not result in increased yield.