Soybean [Glycine max (L.) Merr.] is an important legume crop worldwide due to its rich protein content, oil content, and functional components [1,2]. As a food, soy consumption has historically been associated with Asian countries such as China and Japan, rather than the United States [3]. The basis for food production in many countries is seeds. In addition to their direct consumption, seeds serve as a processed food used in animal feed production [4]. Thus, the importance of soybean (Glycine max L.) as a global crop cannot be overstated, given its dual value as a source of high-quality protein and oil for food production, animal feed, and biofuel industries [5]. The global demand for soybean has been increasing in recent years, due to rapid economic growth in the developing world and depreciation of the US dollar [6]. In response to this demand, its production has been increasing worldwide, through a combination of increased production area and greater yield [7]. At the same time, the growing demand for sustainable production in the face of climate change and resource scarcity emphasizes the need for optimized agronomic practices that enhance productivity without compromising environmental integrity [8]. Soil tillage methods are particularly influential in this context, shaping soil structure, nutrient dynamics, and water availability, all of which directly affect crop performance [9]. The increasing demand for protein in food and fodder has led to efforts to expand soybean cultivation in Poland [10]. For economic, environmental, and climatic reasons, soil cultivation methods without the use of a plow have become increasingly popular in recent decades [11]. Partial plowed tillage with strip-drill sowing has gained attention as an effective strategy that balances yield optimization and soil preservation. This method minimizes the trade-offs associated with other systems, such as direct sowing (zero tillage), which improve the biometric features of plants but often reduce seed quality and germination capacity. Conversely, conventional plowing promotes nutrient availability, particularly enhancing carbohydrate levels, but may not support the long-term goals of conservation agriculture due to its impact on soil degradation. Moreover, strategies to increase the soil carbon pool include soil restoration and woodland regeneration, no-till farming, cover crops, nutrient management, manuring and sludge application, improved grazing, water conservation and harvesting, efficient irrigation, agroforestry practices, and growing energy crops on spare lands [12]. These findings underscore the need for a nuanced understanding of tillage systems tailored to specific agro-ecological conditions. Integrating moderate tillage approaches such as plowed tillage using strip-drilling with sustainable management practices can support soil health, resilience, and productivity. Crop and soil management systems that help to improve soil health parameters (i.e., physical, biological, and chemical) and reduce farmer costs through the development of appropriate equipment are essential for these systems to be successfully adopted by farmers in practice [13]. Modern machinery has made it possible to till strips in a single pass and, at the same time, apply fertilizers and sow seeds. In strip-tillage, strips of deeply loosened soil that are several centimeters to several tens of centimeters wide are prepared for sowing seeds. These strips are separated by strips of untilled soil. The loosened soil strip is narrow, while the width of the non-loosened interrow is greater than that in traditional seed drilling [14]. Creating the right conditions for germination and temperature increases in cultivated strips with plants provides more favorable conditions for development [15]. The cultivation method used by Bojarszczuk and Księżak [1] had a relatively small effect on soybean yield, the content of selected nutrients, morphological features, and elements of the yield structure. However, soil cultivated using the strip-tillage method was more compact than that cultivated with the conventional tillage method. After harvesting soybean at a depth of 30 and 40 cm, the compactness of the soil cultivated with strip-tillage or reduced tillage was much lower than that in spring, indicating the beneficial effect of soybean on loosening the arable layer. Moreover, the benefits of not using plow cultivation with a relatively small reduction in yield compared to that of reduced tillage and strip-tillage show that a lack of plowing does not have significant negative consequences on yield but does reduce time, fuel consumption, and carbon dioxide emissions [11]. These factors are especially important given the commitment to meet the European requirements for reductions in GHG emissions [14]. As it can improve soil quality and reduce the negative impacts of agriculture on the environment, strip-till cultivation technology has the opportunity to be much more widely used in Poland, and may potentially replace traditional plow tillage [15]. Future research should investigate the long-term impacts of these systems under variable climatic and resource conditions to provide a robust framework for sustainable soybean production. Legumes, including soybean, are becoming increasingly popular in Poland due to the demand for fodder protein. Specifically, the area of soybean cultivation is increasing exponentially [15]. Ultimately, the present study hypothesizes that different tillage methods connected with strip drill sowing significantly improve soybean yield and quality by affecting soil structure, nutrient availability, and seed composition.

Table 3 presents the effects of soil tillage and sowing methods (ST/SM) on several plant features: (PN) plant number per 1 m², (PP) number of pods per plants, (PS) number of seeds per plant, (PSP) number of seeds per pod pf plant, (WTS) weight of 1000 seeds (g), (SPAD) leaf greenness index of plants, and (GC) germination capacity (%). ST/SM was found to modify some biometric features and yield components. Compared to PCR, NSD significantly decreased PSP by 13.3%, WTS by 3.5%, and GC by 11.3 but increased PP and SPAD by about 15.0–16.0%. Moreover, there were no significant differences between these ST and SM values in PN. The highest value was observed in ZSD (78.3 plants per square meter), while the lowest occurred in PSD (69.1). Meanwhile, significant differences were detected with LSD = 5.32. ZSD decreased the WTS by 5.7 g, increased SPAD by 10.1%, and improved the GC of PSD by 5.7% when compared to PCR. ZSD generally offered lower performance metrics, which is also in line with findings from various studies suggesting that this tillage method can negatively impact yield quality. ZSD practices often result in less soil aeration, reduced soil warmth, and less nutrient availability, which can affect seed development and plant growth [19]. However, alternatives to plows still offer advantages through savings in terms of fuel, labor, and wear and tear of farm implements [20]. We observed significant increases in the PP and SPAD of NSD plots, despite a decrease in PSP, WTS, and GC. In a previous study by Różewicz et al. [11], the tillage method significantly affected photosynthesis intensity. The increase in SPAD indicates enhanced chlorophyll content in leaves, which is often associated with better photosynthetic efficiency. There are no Polish studies on the strip-till cultivation of soybean [15]. However, Księżak and Bojarszczuk [1] assessed the influence of the tillage method on sowing values such as vigor for soybean seeds using the electrical conductivity vigor test to indicate field emergence. In these trials, the electrical conductivity (EC) test showed the effects of soil cultivation methods for soybean based on the EC of stagnant water. The highest electrical conductivity of standing waters was observed among soybean seeds grown under the strip-tillage method (mean for both cultivars, 12.3 μS∙cm⁻¹∙g⁻¹), while the lowest was observed under the conventional tillage method (mean, 15.2 μS∙cm⁻¹∙g⁻¹). Reduced seed quality and germination capacity under NSD have been commonly observed in other studies evaluating no-till practices. The PSD system yielded the best outcomes for WTS, SPAD, and GC, which aligns with research suggesting that moderate tillage systems balancing soil protection and nutrient availability can improve crop yields. PSD, which likely involves shallower tillage, may create better conditions for root development, water retention, and nutrient availability without compromising the soil structure, as is often the case with full tillage systems [19]. Studies have also shown that integrated tillage systems combining elements of both conventional and no-till practices can offer optimal results for soil properties and crop production. The observed trend of higher plant density in ZSD (78.3 plants/m²) compared to PSD (69.1 plants/m²) could be attributed to differences in seedbed conditions. In a study by Księżak and Bojarszczuk [1], the assessed cultivation methods had a relatively minimal effect on the morphological features and elements of the yield structures of both cultivars, Merlin and Aldana. Although the cultivation method slightly changed the root systems of both soybean cultivars in our study, these differences were observable in the early development phase of soybean (Figure 5).

Table 4 shows the reported chemical composition of the soybean on a dry matter basis. In the soybean seeds, organic components such as protein, lipids, and fiber were not affected by the levels of experimental factors. Similarly to the results of Księżak and Bojarszczuk [1], the assessed cultivation methods had a minimal effect on the concentration of more important nutrients in the seeds of soybean cultivars such as Merlin and Aldana. However, Farmaha et al. [21] noted that the strip-till cultivation of soybean offers positive effects related to yield quality because seeds from strip-till soybean contain more oil and protein compared to those under no-till. Various studies on crop nutrition have shown that organic components, such as proteins and lipids, are often more strongly influenced by genetic factors, plant variety, and environmental conditions [22,23,24]. In an experiment by Fecák et al. [22], the seed protein and oil of soybean were very significantly (p ≤ 0.01) affected by weather conditions; this influence, compared to that of tillage systems and those using nitrogen fertilization, was much higher. These findings agree with the results of Šariková and Fecák [23], who also reported the highest influence of weather conditions on seed protein and oil. Based on a regression analysis, seed protein has a negative relationship with seed oil. According to Długosz [25], reducing soil tillage via the application of catch-crop green mass as a mulch is a conservation practice used in agriculture to improve the soil ecosystem. In our study, significant differences were observed in ash content, with the ZSD treatment yielding a higher value (57.4 g kg⁻¹) than PCR (55.8 g kg⁻¹). Moreover, ZSD had the lowest NFE (256.4 g kg⁻¹), while PCR had the highest (273.3 g kg⁻¹). This result suggests that ZSD might have increased the mineral content of the soybeans. Ash content is primarily composed of inorganic minerals such as calcium, potassium, magnesium, and phosphorus, and its variation can reflect differences in soil nutrient availability. This cultivation method enhances soil organic matter quantity and quality by improving soil biological activity and nutrient availability while reducing soil disturbances [25]. Zero tillage systems that maintain the soil structure and improve nutrient retention may lead to higher concentrations of mineral elements in the seeds due to reduced leaching and enhanced nutrient cycling [15]. Therefore, the higher ash content observed in ZSD could be a result of better soil nutrient conservation and availability. Reduced tillage systems are an important component of soil management in sustainable agriculture [25].

Table 5 investigates the combined influence of ST/SM on seed yield (t ha⁻¹) over three years, providing annual data and the overall mean. This interaction highlights the combined effects of tillage and yearly conditions. In 2017, all methods produced similar yields (2.4–2.7 t ha⁻¹), with no significant differences. Overall, 2018 emerged as the most favorable year across all methods, with yields significantly higher than those in 2017 and 2019. The yield peaked, ranging from 3.0 t ha⁻¹ (PCR, ZSD) to 3.4 t ha⁻¹ (PSD), but the differences were not significant. ZSD outperformed the alternatives in 2019 and had the highest average yield. This result may indicate the resilience of ZSD under less favorable conditions. No significant differences were observed across mean yields. However, overall, ZSD (2.5 t ha⁻¹) had the highest average yield. PCR and PSD offered equal yields (2.4 t ha⁻¹), while NSD had the lowest (2.3 t ha⁻¹) yield. The variability in soybean yield across the three years (2017–2019) in our study underscores the influence of annual environmental conditions, a finding supported by numerous studies. Our results are similar to those of Fecák et al. [22], in which the environmental conditions (years) played a crucial role in determining the seed yield of soybean. In this study, the highest average yield was observed in 2008 (2.77 t/ha), followed by 2.34 t/ha in 2006. The lowest yield was 1.98 t/ha in 2007, during which the stage of seed-filling was found to be the most sensitive to water stress, resulting in a yield reduction. Döttinger et al. [26] emphasized that yearly weather patterns, such as precipitation and temperature, significantly affect soybean productivity. In our study, the significantly higher yields observed in 2018 across all methods reflect favorable climatic conditions, likely optimal moisture and temperature levels during critical growth stages, as described by Tang et al. [27] and Hatfield and Prueger [28]. The effect of weather conditions on soybean seed yields was confirmed by Księżak and Bojarszczuk [1], who found that the soybean yields of two cultivars were significantly influenced by alternating weather conditions (temperature, total precipitation, and distribution) during the growing season and the cultivation methods used in soybean production. The tillage method in years with lower total precipitation had no significant effect on soybean productivity. Only in the last year of experimentation did soybean grown using the conventional tillage method offer a better yield.

The results shown in Table 6 indicate the significant effect of experimental factors and weather conditions on the protein yield of soybean. The differences were significant between PCR and NSD in 2017 (88.8 kg ha⁻¹) and ZSD in 2018 and 2019 (193.5 kg ha⁻¹ and 146.9 kg ha⁻¹, respectively). The relatively uniform protein yield across methods (746.8–864.6 kg ha⁻¹) in 2017 suggests limited environmental stress, allowing for similar performance between tillage and sowing methods. These favorable climatic conditions minimized the influence of soil management practices on yield variability. The peak of protein yield in 2018, particularly with ZSD (1121.6 kg ha⁻¹), reflects optimal growing conditions. The significant performance of ZSD suggests its efficacy in leveraging favorable conditions, possibly due to improved root development and nutrient uptake under reduced soil disturbances [13]. The sharp decline in protein yield across methods (385.2–600.1 kg ha⁻¹) in 2019 highlights the impact of adverse environmental conditions such as drought and excessive rainfall. Protein synthesis in soybean is sensitive to abiotic factors such as temperature, soil moisture, and nutrient availability [28]. In a study by Księżak and Bojarszczuk [1], the most favorable conditions affecting soybean productivity occurred in the third year of research (2020), with seed and protein yields being 80% higher than those in 2019 and approximately 50% higher than those in 2018. According to Hatfield and Prueger [28], adequate precipitation and moderate temperatures enhance nitrogen assimilation, a key factor in protein production. This phenomenon increased the protein yield per hectare, which is particularly important for this crop in terms forage protein production [15]. On average, ZSD significantly increased the protein yield by about 14% compared to the results under PCR. Conservation tillage methods such as ZSD outperformed others, demonstrating resilience under stress by better maintaining soil moisture and reducing compaction [29].

The data in Table 7 highlight the significant influence of tillage practices, sowing methods, and environmental conditions on fat yield. On average, there were no significant differences between the control (PCR) and other ST/SM options, nor were there differences in 2018 and 2019. In 2017, NSD decreased fat yield by 65.4 kg ha⁻¹ compared to that under PCR. NSD consistently underperformed, with the lowest mean fat yield (430.8 kg ha⁻¹). The results of our experiment suggest that soil tillage and sowing methods influenced fat yield even under relatively stable environmental conditions. Conservation tillage methods such as ZSD may have increased soil organic matter retention, thereby improving soil quality and indirectly affecting fat content in soybean seeds [30]. This situation could directly influence fat yield based on the counting method. The substantial annual variation in fat yield underscores the importance of environmental conditions. High fat yields in 2018 coincide with favorable growing conditions, while decreases in 2019 highlight the impact of stress factors. Conservation tillage methods are better equipped to mitigate these stresses by improving soil health and moisture retention [31]. The significant Tillage × Year interaction (LSD = 89.20, p < 0.01) emphasizes that a combination of tillage methods and environmental conditions strongly influences fat yield. As soybean fat content is sensitive to abiotic stresses such as water deficits and extreme temperatures [32], conservation tillage methods such as ZSD can help stabilize yields under variable conditions. Moreover, soybean is mainly used as an oilseed crop. Consequently, higher oil content in the seed is important to ensure seed quality, but the remaining post-extraction soybean meal after oil pressing is also an important protein component for feed production [15].

The present correlation analysis underscores the complex relationships among biometric and yield-related traits in soybean cultivation (Figure 6). We observed a nearly perfect correlation between plant density (PN) and germination capacity (GC). TeKrony and Egli [33] noted that seed viability and vigor directly affected the performance of seeds planted to regenerate the crop. Although seed quality can influence many aspects of performance (e.g., total emergence and rate of emergence), the objective of this research was to examine the relationship between seed vigor and one aspect of performance: crop yield. The strong positive correlations among seed yield (SY), protein yield (PY), and fat yield (FY) align with the experiment of Singh et al. [34], who demonstrated that seed composition and overall yield are co-dependent traits influenced by genetic and environmental factors. This finding emphasizes the interconnected nature of yield components and the potential for breeding programs to enhance multiple traits simultaneously. The robust relationship between pods per plant (PP) and PN supports the hypothesis of resource competition under high plant densities, as noted by Board and Kahlon [35]. These authors observed that higher densities often limit individual plant access to sunlight, nutrients, and water, thereby reducing pod production per plant. This analysis highlights the need for balanced strategies to optimize plant density and enhance resource use efficiency. Future studies should consider integrating environmental variables such as soil fertility and moisture levels alongside management practices such as tillage and row spacing. These approaches align with the adaptive management strategies suggested by Kelly et al. [36], which emphasize the importance of tailored interventions for site-specific conditions to maximize soybean yield and quality. Indeed, the sustainability of all cropping systems could be increased by implementing better management techniques such as zero and reduced tillage with residue retention and using better nutrient sources [37]. Determining how management approaches affect different crops and cropping systems is crucial to achieving high food production and comparing crop management practices under different cropping systems [38].