Although essential for achieving high crop yields required for the growing population worldwide, nitrogen, (N) in large amounts, along with its inefficient use, results in environmental pollution and increased greenhouse gas (GHG) emissions. Therefore, improved nitrogen use efficiency (NUE) has a significant role to play in the development of more sustainable crop production systems. Considering that wheat is one of the major crops cultivated in the world and contributes in high amounts to the large N footprint, designing sustainable wheat crop patterns, briefly defined by us in this review as the 3 Qs (high quantity, good quality and the quintessence of natural environment health) is urgently required. There are numerous indices used to benchmark N management for a specific crop, including wheat, but the misunderstanding of their specific functions could result in an under/overestimation of crop NUE. Thus, a better understanding of N dynamics in relation to wheat N cycling can enhance a higher efficiency of N use. In this sense, the aim of our review is to provide a critical analysis on the current knowledge with respect to wheat NUE. Further, considering the key traits involved in N uptake, assimilation, distribution and utilization efficiency, as well as genetics (G), environment (E) and management (M) interactions, we suggest a series of future perspectives that can enhance a better efficiency of N in wheat.

Peppermint (Mentha × piperita L.) is perennial plant cultivated for essential oil production. In the present study, field experiments were conducted to determine the performance of peppermint under different cultivation systems for two consecutive growing periods in 2015 and 2016. The effects of environmental conditions on peppermint biomass yield and oil content was also evaluated. The experiments were carried out according to randomized complete block design with five replications per cultivation system. The results of the present study indicate that the total aboveground dry weight and dry leaves biomass were affected by cultivation system and year. For both growing seasons, the highest values were found under the conventional farming system. In contrast, oil content was approximately 14% higher in organic system than in conventional system. Moreover, oil content differed by year, with higher values being observed in 2015 comparing to 2016. Both oil content and biomass yield were positively affected by high temperatures. The results from this study demonstrated that both environmental conditions and the cultivation systems affect the biomass and oil content in peppermint crop.

Assessing the efficiency of nitrogen application is a valuable first step in establishing an optimum N fertilizer management plan. The aim of this study was to elaborate a sustainable N management system for sown grassland installed in temperate regions, through manipulation of nitrogen use efficiency and nitrogen response efficiency (NRE) indicators. Research was performed in western Romania. The biological material consists in two forage species of major importance for the forage base worldwide, namely Trifolium pratense L. and Lolium multiflorum Lam., in pure stands and in mixture. Both forage species were sown at two different spacings between rows (12.5 and 25.0 cm) and were fertilized with nitrogen (N) in three doses (N0-control, N50-fertilized with 50 kg N ha−1 and N100-fertilized with 100 kg N ha−1). The studies were made in 2016 and 2017, years very different from each other in matter of rainfalls. The results revealed a different behavior of the three sward types analyzed: while in Trifolium pratense monoculture and in the mixture of the two species studied, less N was removed than was applied; on the other hand Lolium multiflorum monoculture used a high proportion of the N applied, being at the limit to access N from the organic pool or residual N from fertilizer applications to a preceding crop.

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.

There is currently a lack of knowledge regarding the effectiveness of the Natura 2000 (N2000) network in providing protection against biological invasion by invasive alien species (IAS). In this study, we analyzed two Salix alba and Populus alba riparian habitats located both inside and outside a N2000 site from Romania in order to assess the efficacy of N2000 network in conserving this type of ecosystem against IAS. Field investigations were conducted both using polygon method for vegetation study and semi-structured interviews focusing on the local people knowledge and their contribution to biological invasion. We found that the research area located within the N2000 network is highly exposed to biological invasion by IAS, the major threat to this type of habitat being expressed by Acer negundo, which occupied more than half of the vegetation cover. It seems that not only the management strategy should be blamed for this situation, but rather its failure in popularization and application. As such, in our opinion, future management plans developed by N2000 network should rely on the intertwined co-evolutionary mechanisms existing between poplar and willow stands diversity and cultural diversity, by integrating aspects related to local traditional knowledge.