Soybean is one of the most important sources of vegetable protein, having a great agronomic importance by fixing atmospheric nitrogen following symbiosis with bacteria of the genus Rhizobium. Bifactorial experience, of the AxB model A - phosphorus doses: P0; P40; P80; P120; P16 and B - nitrogen doses:N0; N25; N50; N75; N100, aims to identify the influence of these doses on the development of soybean cultivation. Although soybeans are a heavy consumer of nitrogen and phosphorus in the early stages of development, however, they do not react well to large amounts of nitrogen as they prevent the development of the number of nodules on soybean roots and inhibits the growth of bacteria, and the increases obtained production do not justify the higher amount of nitrogen applied to soybeans. The number of pods and the mass of 1000 grains are also influenced more by the application of phosphorus doses than  nitrogen. Phosphorus applied in higher amounts leads to an increase of over 60% of the number of nodules but also at significant production increases of 5-7%, compared to the non-fertilized variant. On nutrient-rich soils, soybeans do not require fertilization with large amounts of nitrogen, but they react very well to the application of phosphorus fertilizers.

Presented research was carried out in 2021 and 2022 on the Felix soybean variety at the Agricultural Research and Development Station Turda, located in the Transylvanian Plain, Romania. In this experiment, complex fertilizer NPK 20:20:0 was applied as a basic fertilizer in a dose of 200 kg ha−1 at the sowing stage, to which foliar fertilizer Agro Argentum Forte treatment was added in different doses and at different application stages. The main purpose of the study was to identify the suitable stages of foliar application in soybean cultivation for effective vegetative development, yield, and quality purposes. The impacts of the fertilization system and the climatic conditions on the physiological parameters, assimilation, yield, and quality were evaluated. Technology showed that the physiological parameters were positively influenced, following the foliar fertilization with Agro Argentum Forte, with average assimilation values recorded above 23.0 μmol CO2 m−2s−1 in the year 2021 and 22.4 μmol CO2 m−2s−1 in the year 2022. Soybean crop was influenced by climatic conditions and the application of foliar fertilizers in different phases of growth and development, obtaining higher yields, as well as higher protein and oil content. The soybean yield and quality indices (protein, oil, and mass of a thousand seeds) were higher in 2021 than in 2022 for the variants treated with foliar fertilizers compared to the control, resulting in an improvement in seed quality in 2021 with a yield of 3560 kg ha−1, while 2022 saw a lower yield of 1805 kg ha−1. The application of basic mineral fertilizers in combination with foliar fertilization had a significantly positive impact on the quality indicators of soybean seeds. The highest yields were achieved when the foliar treatment was applied in the early pod formation stage.