Winter oilseed rape is the main oilseed crop in Latvia. High yield production depends on applied plant nutrients, especially nitrogen. Nitrogen is one of the most mobile plant nutrients in the soil and, therefore, nitrogen fertilizer management is an important part of agriculture. The objective of this paper is to evaluate the effect of nitrogen fertilizer rate on nitrogen use efficiency (NUE) in winter oilseed rape. The field experiment was conducted during four growing seasons (2014/2015, 2015/2016, 2016/2017 and 2017/2018) at the Research and Study farm ‘Pēterlauki’ of Latvia University of Life Sciences and Technologies (56° 30.658´ N and 23° 41.580´ E). In total, eight nitrogen rates were used in this experiment (kg ha-1 of N pure matter): N0 or control, N60, N90, N120 (80+40), N150 (100+50), N180 (120+60), N210 (120+60+30) and N240 (140+60+40). All NUE parameters were calculated only for five nitrogen rates (N0; N60, N120, N180 and N 240). Results indicated that the nitrogen fertilizer rate had a significant (p is less than 0.001) effect on winter oilseed rape seed yield. The yield increased until the rate N120 – N180. Nitrogen fertilizer rate also significantly (p is less than 0.001) affected N, P2 O5 and K2 O removal with oilseed rape biomass. N and K2 O removal with seed yield significantly increased until the nitrogen rate N120 – N180, but P2 O5 until N60 – N180. Results showed that the nitrogen fertilizer significantly (p is less than 0.001) affected NUE, nitrogen uptake efficiency (NUpE) and nitrogen utilization efficiency (NUtE), but it did not have a significant (p=0.840) effect on nitrogen harvesting index (NHI). By increasing the nitrogen fertilizer rate, NUE, NUpE and NUtE decreased.

Melon seeds have been recognized as a nutritional powerhouse, offering a range of essential vitamins and fatty acids that play a critical role in maintaining and enhancing our health. This study aims to analyse the fatty acid profile and water-soluble vitamins in melon seeds in order to highlight the importance of incorporating melon seeds into our diets, not only as a source of nutrients but also as a means of promoting overall health and well-being. It delves into the rich nutritional profile of melon seeds, underscoring their valuable contribution to a balanced diet. Water soluble vitamins C, PP and B1 were detected in melon seeds in this study. Regarding fatty acid profile, PUFA C18:2 was the most abundant (35.31%), followed by MUFA C18:1 (25.83%), although other unsaturated and saturated fatty acids were also determined. This comprehensive analysis of melon seeds’ nutritional benefits encourages further exploration of their potential in enhancing diet quality and supporting long-term health objectives.