## 1 Introduction
Minimizing the N surplus is a key target of the F2F strategy as part of a broad effort to mitigate the impact of agriculture on both global change and environmental pollution [8, 9, 10]. However, a critical concern of adopting mitigation practices based on the reduction of N fertilization is the potential trade-off in yields [10,11]. It should be emphasized at this point that adoption of the F2F strategy is expected to result in a slight decrease in yields under current climatic conditions, but this effect is likely to be compensated in the future (mid-century) by positive effects of increased carbon dioxide [CO2] levels [9,10]. It is also necessary to mention that before F2F, in the context of the NO3\({}^{-}\) environmental problem, in 1991, the Council Directive 91/676/EEC was applied, concerning the protection of waters against pollution caused by NO3\({}^{-}\) from agricultural sources. Under this directive, farmers across Europe have implemented numerous practices to reduce NO3\({}^{-}\) levels in water, particularly in designated Nitrate Vulnerable Zones [NVZs] [12]. NVZs are areas where groundwater or surface water is at a high risk of NO3\({}^{-}\) pollution due to agricultural runoff. In these zones, farmers must follow specific regulations to minimize NO3\({}^{-}\) leaching, such as restricted fertilizer application periods and mandatory buffer zones along waterways. The Nitrates Directive prohibits farmers from applying fertilizers on soils that are surface-frozen, covered with snow, or waterlogged, as fertilizers cannot be absorbed by the soil under these conditions and can easily leach into water sources. Additionally, farmers must observe designated fertilization periods and maintain minimum distances between fertilizer application areas and flowing or standing water bodies. Farmers across Europe have implemented a variety of practices to mitigate NO3\({}^{-}\) pollution [12]. These include the development of comprehensive nutrient management plans, supported by soil sampling and nutrient budgeting techniques. Increasingly, precision agriculture tools, such as GPS sensors, are being employed to optimize fertilizer application across different field zones, and GPS scanning data are used to establish databases that can be used to monitor soil conditions [12]. This precision helps reduce the risk of excessive NO3\({}^{-}\) application in specific areas, thereby minimizing environmental impact. One of the measures farmers are taking to support the idea of fertilizer reduction is the increasing use of crop rotation with legumes, which is a key agricultural practice that offers multiple environmental and economic benefits, aligning closely with the EU's F2F strategy. One of the primary benefits of including legumes in rotation systems is their ability to naturally fix N in the soil [13]. Unlike many other plants, legumes form symbiotic relationships with N-fixing bacteria, capturing atmospheric N and converting it into forms that plants can absorb and use [8,13]. This process enriches the soil and reduces the need for synthetic fertilizers, which are energy-intensive to produce and can contribute to greenhouse gas emissions [13]. By decreasing fertilizer dependency, legume rotation addresses both environmental sustainability and climate objectives central to the F2F strategy. The integration of these practices is essential for improving nutrient use efficiency and ensuring compliance with EU regulations designed to protect water quality and reduce eutrophication risks [12,13]. Consequently, it is essential to conduct extensive environmental research to better understand the impact of the moderate use of synthetic fertilizers, particularly N-based ones. Such studies should focus on developing fertilization strategies that balance the need for high yields with the need for environmental and public health protection.