Nitrogen uptake from various sources by plants capable of biological reduction of N₂ in symbiotic systems with root nodule bacteria is influenced by many factors. The aim of the study was to examine the influence of the development stage and variety of pea (Pisum sativum L.) cultivated in years with different temperature and precipitation conditions on the dynamics of nitrogen uptake from the atmosphere (Ndfa), fertilizer (Ndff), and soil (Ndfs). Pre-sowing nitrogen fertilization with the ¹⁵N isotope and the isotope dilution method were used in the research. The highest rate of Ndfa uptake was noted between the three-internode stage and the stage of the first visible flower buds outside the leaves, while Ndff and Ndfs uptake was highest between the 4-leaf stage and the 3-internode stage. The lowest rate of Ndfa uptake was noted from sowing to the four-leaf stage, while Ndff and Ndfs uptake was lowest between the stage when 50% of pods were of typical length and full maturity. Nitrogen uptake from all sources was similar for all pea cultivars, but significantly depended on the variable temperature and precipitation conditions (years of the study).

Molybdenum (Mo), boron (B), and iron (Fe) play an important role in symbiotic nitrogen fixation by legume plants. The intensity of this process varies in different growth stages of legumes, and the changes are accompanied by changes in the content and translocation of these micronutrients in the plant. A two-year field experiment was conducted to investigate the dynamics of molybdenum, boron, and iron content, translocation, and accumulation in pea plants. Two pea cultivars were studied in six stages of growth, from the four-leaf stage to full maturity. The content of Mo, B, and Fe in the roots of pea was highest from the four-leaf stage to the full flowering stage, i.e., the period of establishment of symbiosis and the most intensive atmospheric nitrogen fixation. The bioaccumulation factors of Mo and Fe were generally highest in the initial stages of pea growth and decreased during generative development, while the reverse pattern was observed for boron. The bioaccumulation factors also indicate high bioaccumulation of Mo and B and low bioaccumulation of Fe in the biomass of pea. The translocation factor indicated a high potential for allocation of Mo from the roots to the aerial parts, increasing during growth; high and stable potential for allocation of boron; and very minor allocation of iron to the aerial parts. The values of all parameters tested were usually dependent on the conditions in which the experiment was conducted (the year), but not on the cultivar of a pea.

Soybean has the ability to live in symbiosis with microorganisms and take up nitrogen from the atmosphere, fertiliser and soil reserves. The amount of nitrogen taken up from these sources depends on many biotic and abiotic factors, e.g., the rhizobium species, cultivar, as well as weather and agricultural conditions. A field experiment was conducted in eastern Poland (central Europe) in two successive growing seasons to examine the uptake of nitrogen from the atmosphere (NDFA—% nitrogen derived from the atmosphere), fertiliser (NDFF—% of nitrogen derived from fertiliser) and soil reserves (NDFS—% of nitrogen derived from the soil) for three non-GMO (non genetically modified organism) soybean cultivars: Abelina, SG Anser and Merlin. Pre-plant fertilisation of plants with nitrogen excess with the ¹⁵N isotope and the isotope dilution method were applied. Soil reserves and the atmosphere were major nitrogen sources for soybean. Soybean roots contained the most atmosphere-derived nitrogen (45.85%), the amount being lower for soil reserves (41.43%) and the lowest for fertiliser (12.72%). Harvest residues and seeds contained the most soil reserve-derived nitrogen, the amount being lower for the atmospheric nitrogen and the lowest for fertiliser-derived nitrogen. The amount of nitrogen derived from different sources in the whole soybean mass significantly depended on cultivars and years’ percentage values being affected by study years only. Less atmospheric nitrogen was accumulated in cv. Abelina roots (2.15 kg N·ha⁻¹) compared with cv. SG Anser (3.07 kg N·ha⁻¹) or cv. Merlin (2.89 kg N·ha⁻¹). More atmospheric nitrogen was recorded in the post-harvest residues and seeds of cv. Abelina and SG Anser than Merlin. The content of soil reserve-derived nitrogen taken up by the whole soybean plants averaged 61.29 kg N∙kg⁻¹, the amounts being 50.95 and 11.38 kgN∙kg⁻¹ for nitrogen taken up from the atmosphere and fertiliser, respectively. Soybean grown in the study year with more favourable thermal and precipitation conditions (2017) took up more nitrogen from all the sources compared with the year 2018.

The sources of nitrogen for yellow lupine and spring triticale in their intercropping | Andrzej Wysokiński, Beata Kuziemska | Agricultural Journals

Copper is a microelement involved in the metabolism of nitrogen compounds in plants. Good utilization of nitrogen from soil and fertilizers by plants requires an adequate supply of copper. The aim of the study was to determine the effect of increasing levels of copper (100, 200, and 300 mg Cu·kg⁻¹ of soil) applied together with various organic fertilizers (cattle manure, chicken manure, and spent mushroom substrate) on nitrogen content and uptake by cocksfoot (Dactylis glomerata L.) and the coefficient of nitrogen utilization from organic fertilizers. The pot experiment was carried out in three growing seasons (May–September) in greenhouse, and in this cocksfoot was grown and harvested four cuts in each year. Copper and organic fertilizers were applied once in the first year before sowing cocksfoot, and the after-effect was investigated in the second and third years. Application of different amounts of copper did not influence the nitrogen content in the biomass of cocksfoot. At the same time, soil application of this micronutrient in the amount of 100 mg Cu∙kg⁻¹ of soil caused an increase in nitrogen uptake in the biomass of cocksfoot. Application of 100 and 200 mg Cu·kg⁻¹ of soil caused an increase in the coefficient of nitrogen utilization from the organic fertilizers, which was highest effect in the case of cattle manure. All of the organic materials used increased the content of nitrogen and its uptake by cocksfoot, but the greatest effect was noted following application of chicken manure. The study showed no synergistic or antagonistic relationships between copper and nitrogen.

Different content of Zn in the soil and organic fertilization can affect micronutrient uptake by plants. A pot experiment was carried out to determine the impact of increasing Zn application rates, i.e., 200, 400 and 600 Zn mg·kg⁻¹, in combination with bovine and chicken manures and mushroom substrate on Cu and Ni content, uptake and bioaccumulation factor in cocksfoot (Dactylis glomerata L.). Control objects without Zn and organic fertilizers and after application of only different Zn doses and only organic fertilizers were also tested. Application of Zn at 400 and 600 mg·kg⁻¹ significantly decreased the content, uptake and value of bioaccumulation factor of Cu in the grass. Different Zn doses were not found to influence the content and bioaccumulation factor of Ni in cocksfoot, but application at 200 Zn mg·kg⁻¹ increased Ni uptake. Chicken manure increased the content and bioaccumulation factor of Cu and Ni in the test plant, and all the organic fertilizers increased their uptake. Cocksfoot showed no tendency to excessive bioaccumulation of Cu and Ni.