Legumes are increasingly important crops in most European Union (EU) countries because of the growing demand for feed protein, and also because they have been shown to improve the characteristics of soil. The main part of the crop rotation is taken up by cereals, but they are connected with undesirable side effects, such as the unilateral utilization of ingredients and the heightened risk of plant diseases, e.g., Fusarium. Simplification of farming methods has become increasingly popular as growers search for cheaper production technologies. However, the effects of long-term simplification in tillage practices on the production and economics of narrow-leafed lupine (NL) cultivation have not been studied. In 2012–2016, we carried out a field experiment in Poland with a one-factorial design with four replications. The aim of the experiment was to evaluate the productivity effect of conventional tillage (CT), reduced tillage (RT) and no-tillage (NT) on NL-winter wheat (WW)-winter triticale (WT)-winter barley (WB), rotation. Our results show that the productivity of this crop rotation was lower under RT and NT systems than under CT. From a practical point of view, the reduction of cultivation in rotation with 75% of cereals caused a decrease in yield in all species, which can result in resign of using the RT and NT in conditions of Albic Luvisols soil, as classified according to the World Reference Base (WRB). The highest incomes were found when the CT system was used with NL. Although income losses exceeded the value of savings in both minimalized soil tillage systems (RT and NT), all tillage systems of NL were profitable.

Phytostimulators are attracting considerable attention for replacing mineral fertilizers, which are of environmental concern, being especially forbidden in organic farming. The benefit of applying such products based on microorganisms (e.g., algae extract) or minerals of nano-meter-sized particle (e.g., nanofertilizers) is that plants can uptake them faster than soil fertilizers, targeting plant growth by regulating their phytohormones, as well as improving plant tolerance to unfavorable environmental conditions (e.g., cold stress). The aim of this study was to test and evaluate the effects of three commercial phytostimulators, called biostimulants (a seaweed-based extract—Kelpak^®, mineral nanoparticles—Nano Active^®, zinc nanoparticles—Dynamic Cresco^®) on yield, chlorophyll content, level of CO₂ assimilation and the effectiveness of PSII under cold stress. The values of all chlorophyll fluorescence and photosynthetic parameters significantly decreased under cold, which indicated a strong inhibition of light-phase photosynthesis in maize leaves. Predicted by the regression analysis minimum, 20 days was enough for maize plants to recover from the inhibition caused by stress damages in their photosynthetic apparatus. At the final measurement in maize growth stage BBCH 65, all the tested phytostimulators showed significant effects in increased values of effective quantum yield of photosystem II, maximum photosynthetic efficiency of PSII and electron transport rate. At this stage, Dynamic Cresco^® and Nano Active^® treatment significantly increased the value of maximum net photosynthetic rate (15.37% and 18.85%, respectively) and leaf chlorophyll content (7.8% and 8.7%, respectively). The application of Dynamic Cresco^® significantly promoted total dry weight by 43.4% in comparison to control under stress growth conditions with cold. These phytostimulators can be used to enhance yield and physiological status of plants after abiotic stress (such as cold) to improve crop productivity, especially in organic farming.

The field experiment was carried out in 2013 and 2014 as part of a long-term experiment to test the influence of different soil tillage systems (conventional, reduced, direct sowing) on (a) the yield of summer pea (Pisum sativum L.) and (b) the amount of biologically reduced atmospheric nitrogen (N), which was determined using the ¹⁵N dilution method (ID¹⁵N). Spring barley was used as a reference plant. Climatic conditions did not have a significant influence on the yield of pea seeds (mean value 4.56 t ha⁻¹), post-harvest residues (3.76 t ha⁻¹) and total biomass (8.33 t ha⁻¹). Soil tillage system was found to have a significant impact on all components of the pea yield in years of experiment, with the highest average seed yield values observed with the conventional system (5.19 t ha⁻¹) and significantly lower values observed with reduced tillage (4.34 t ha⁻¹) and direct sowing (4.17 t ha⁻¹). The content of total N was greatest in the pea biomass that was harvested in the conventional system (202 kg ha⁻¹) and lowest with direct sowing (155 kg ha⁻¹). Nitrogen accumulated in the pea seeds from three sources: atmosphere (mean value 35.2%), fertilizers (6.8%) and soil (57.9%), equating to 48.6, 9.9, and 85.4 kg ha⁻¹, respectively. Soil tillage system was found to have a significant impact on the amount of N that was fixed from the atmosphere by the peas: 17.7% in conventional tillage, 37.9 in reduced system and 50.2% in direct sowing, which equates to a harvested seed yield of 28.9, 52.0 and 64.4 kg ha⁻¹, respectively. In the post-harvest residues, the amount of N fixed from the atmosphere by the pea crop was also modified by the soil tillage system in range: 20.2% in conventional tillage and 32.6% in direct sowing (which equates to 7.4 and 8.5 kg N ha⁻¹, respectively), but the difference was not significant.

The aim of this study was to assess the effect of selected biostimulators and foliar fertilizers on plant development, plant yield, soil fertility and soil biochemical activity (dehydrogenases, phosphatases, catalases) during the cultivation of pea (Pisum sativum L.). A field experiment was conducted between 2016 and 2018 at the Gorzyń Experimental and Educational Station, Poznań University of Life Sciences in Poland. The following treatments were tested: (1) control; (2) Titanit; (3) Optysil; (4) Metalosate potassium; (5) Rooter; (6) Bolero Mo; (7) Adob Zn IDHA; (8) Adob B and (9) Adob 2.0 Mo. Adob Zn IDHA stimulated yields, especially under average moisture conditions and less so in drought conditions, and the differences compared to control amounted 8.36 and 4.3%, respectively. The results showed a close relationship between the effects of the biostimulators and foliar fertilizers and weather conditions during the study. It was not possible to determine whether any of the biostimulators or foliar fertilizers had a positive effect on pea seed yield in any year. Similarly, it was difficult to clearly determine the effect of the biostimulators and fertilizers on biochemical activity in the soil, although soil enzyme activity was influenced most by application of the Bolero Mo fertilizer. In all study years, biological nitrogen fixation was always greater after the application of a biostimulator/fertilizer treatment.

The cultivation of soybeans, especially where this species has not been grown in large areas, requires the determination of the optimal mineral nitrogen fertilization and seed inoculation with Bradyrhizobium japonicum. The purpose of the study was to determine the optimal dose of mineral N fertilization and seed inoculation treatments with B. japonicum under field conditions in the southeastern Baltic region. The objective of this study was to achieve nitrogen supply and/or inoculation with B. japonicum: check-0 kg N ha⁻¹, 30 kg N ha⁻¹, 60 kg N ha⁻¹, HiStick^® Soy + 0 kg N ha⁻¹, Nitroflora + 0 kg N ha⁻¹, HiStick^® Soy + 30 kg N ha⁻¹, HiStick^® Soy + 60 kg N ha⁻¹, Nitroflora + 30 kg N ha⁻¹, Nitroflora + 60 kg N ha⁻¹. Higher yields of seeds, protein and fat were found after application HiStick^® Soy compared to Nitorflora. The inoculation with B. japonicum together with nitrogen fertilization improved crude protein content in seeds, biometrical features, yield components and especially the seed yield of ‘Aldana’ soybean. The highest seed yield was found after the application of HiStick^® Soy and nitrogen fertilization in doses 30 kg N ha⁻¹ or 60 kg N ha⁻¹. Compared to the control, combined B. japonicum inoculation and nitrogen fertilization in soybean cultivation proved to be a significant factor in improving the productivity of this species in southeastern Baltic conditions.

A field experiment was carried out in 2016–2018 in a white lupin (Lupinus albus L.)-winter wheat (Triticum aestivum cv. ‘Bogatka’) crop rotation. The aim of this study was to determine the amount of nitrogen (N) that was biologically fixed by the white lupin crop in the first year of the rotation and to estimate how much of this N was then taken up from the lupin residues by winter wheat in the second and third years of the rotation. Biologically fixed N was determined by the isotope-dilution method (ID¹⁵N) by applying 30 kg N ha⁻¹ of ¹⁵N-labeled fertilizer (¹⁵NH₄)₂SO₄ (containing 20.1 at.% ¹⁵N) to the white lupin and the reference plant spring wheat. The yields of white lupin seeds and crop residues were 3.92 t ha⁻¹ and 4.30 t ha⁻¹, respectively. The total amount of N in the white lupin biomass was 243.2 kg ha⁻¹, which included 209.3 kg ha⁻¹ in the seeds and 33.9 kg ha⁻¹ in the residues. The ¹⁵N-labeled residue of white lupin was cut and ploughed into soil. Our results indicate that 111.2 kg N ha⁻¹ was fixed from the atmosphere by the lupin plants, with 93.7 kg ha⁻¹ found in the seeds and 17.5 kg ha⁻¹ in the residues. In the second and third years of the rotation when winter wheat was cultivated, the plots were divided into two groups of subplots (1) without N-fertilization (control) and (2) with an application of 100 kg N ha⁻¹. In the first year of winter wheat cultivation, 20.0% and 21.0% of N from the crop residues was taken up by the control and N-fertilization plots, respectively, while in the second year, uptake was lower at 7.12% and 9.27% in the control and N-fertilized plots, respectively.