Agronomic Biofortification: Enhancing the Grain Nutritional Composition and Mineral Content of Winter Barley (Hordeum vulgare L.) Through Foliar Nutrient Application Under Different Soil Tillage Methods

Abstract

Enhancing the nutritional content of crops is crucial for safeguarding human health and mitigating global hunger. A viable method for attaining this goal is the planned implementation of various agronomic practices, including tillage and nutrient provision. A field experiment was executed at the Hungarian University of Agriculture and Life Sciences in Gödöllő in the 2023 and 2024 growing seasons. The study aimed to assess the effects of foliar nutrient supply and soil tillage methods on the grain nutritional composition and mineral content of winter barley. Employing a split-plot design with three replications, the experiment included four nutrient treatments (control, bio-cereal, bio-algae, and MgSMnZn blend) and two soil tillage types (i.e., plowing and cultivator). The results indicated that while protein content was not influenced by the main effects of nutrients and tillage, the levels of β-glucan, starch, crude ash, and moisture content were significantly (p < 0.05) affected by the nutrient treatments and by growing year, treated as a random factor. Notably, bio-algae and bio-cereal nutrients, combined with cultivator tillage, enhanced β-glucan content. All applied nutrient treatments increased the level of starch compared to the control. With regard to grain mineral content, the iron and zinc content responded to the nutrient supply, tillage, and growing year. However, applying a multiple-nutrient composition-based treatment did not increase iron and zinc levels, suggesting that individual applications may be more effective for increasing the content of these minerals in grains. Cultivator tillage improved iron and zinc levels. Moreover, manganese (Mn) and copper (Cu) were predominantly affected by nutrient availability and by growing seasons as a random factor. Therefore, to improve grain quality, this study emphasizes the significance of proper nutrient and tillage methods by focusing on the intricate relationships between agronomic techniques and environmental factors that shape barley’s nutritional profile.

1. Introduction

Agriculture is a fundamental pillar of the global economy, supporting a vast array of crops and animal products [1]. Cereal crops, in particular, constitute over 50% of total crop production worldwide, serving as critical sources of food for humans and animals and supporting various industries [2]. Among cereals, barley (Hordeum vulgare L.) holds significant importance, ranking as the fourth-largest cereal crop globally [3]. As one of the ancient cultivated crops, barley has sustained human populations for thousands of years [4]. Its reliability as a food source is emphasized by its ability to thrive during both main and short rainy seasons, as well as in regions with limited moisture [5]. Farmers are particularly drawn to it due to its remarkable adaptability to challenging environmental conditions, coupled with its ability to deliver maximum and economically efficient yield [6,7].

Barley has significance that spans across various domains, including food production, beer brewing, and animal feed [8]. It is rich in fiber, notably β-glucan, which helps to protect against heart disease, high blood pressure, and diabetes [9,10,11]. This beneficial fiber, β-glucan, is a soluble non-starch polysaccharide composed of linear chains of glucose [12]. Additionally, the grains of barley contain prominent phenolic compounds such as gallic acid, benzoic acid, and syringic acid, which contribute to their antioxidant activity and potential health benefits [13]. It is also rich in minerals, vitamins (especially vitamin E), antioxidant polyphenols, and complex carbohydrates (mostly starch), and it has a low fat content and a well-balanced protein composition that meets amino acid requirements [14]. These nutritional quality traits have earned barley recognition as a nutritious and functional food with a significant contribution to nutritional security [15]. While barley is a significant source of nutrition and has various industrial applications, its quality can be affected by several agronomic factors. This can limit its potential to contribute to global nutritional security, especially as the population continues to grow. Thus, addressing these quality issues is crucial in order to fully harness barley’s benefits for human health.

Globally, malnutrition, sometimes known as hidden hunger, is one of the world’s main health issues [16]. According to the World Health Organization report, more than two billion people globally are affected by mineral deficiencies [17]. Similarly, the anticipated rise of two billion people by 2050, along with the risk of hunger and malnutrition affecting a billion individuals, is expected to aggravate the challenge of global nutritional food security in the coming decades [18,19]. This indicates there is a continuous need to enhance the nutritional composition of cereal grains like winter barley, due to rising grain consumption. However, enhancing the nutritional composition in crops like winter barley is not straightforward, as it depends on a range of production factors, including nutrient availability, genetic variation, climate conditions, and tillage practices [20]. To overcome these problems, several agronomic management strategies, such as variety selection, proper nutrient supply, and appropriate soil tillage, have been proposed to produce high-quality grains with improved nutritional content [21].

In the face of these challenges, targeted agronomic strategies are crucial for improving the nutritional quality of winter barley grains, especially concerning soil tillage practices and nutrient availability [22]. Agronomic biofortification, which involves the intentional use of agricultural inputs to boost the micronutrient content of edible plant parts, is a promising method for enhancing the mineral composition of cereal crops [23]. Foliar nutrient applications, in particular, have proven effective in increasing grain nutrition and the accumulation of essential micronutrients in cereal crops like winter barley grains [24]. This is because foliar feeding delivers nutrients directly to plant leaves, bypassing potential soil-related losses and allowing for the rapid correction of deficiencies during critical growth stages [25]. Recent studies have demonstrated that the application of nutrient-rich inputs, such as biogas waste treatment, can significantly enhance the nutritional composition of barley grains, offering valuable benefits for both human and animal consumption [26]. Similarly, field experiments using various mineral fertilizer treatments have shown marked improvements in the micronutrient content of barley crops [27], indicating the potential of nutrient management strategies to enhance grain quality. Moreover, the application of chelated micronutrient blends and biologically active foliar formulations such as seaweed extracts and amino acid-based fertilizers has been shown to improve nutrient uptake efficiency and translocation to developing grains by stimulating enzymatic activities and photosynthetic performance [28]. Recent findings further confirm that foliar applications of micronutrient mixtures and bio stimulants can significantly increase both the mineral density and overall nutritional value of cereal grains, particularly under nutrient-deficient soil conditions [29]. These results suggest that, beyond improvements in yield and grain biomass, foliar nutrient treatments play a critical role in enhancing the bioavailability of essential minerals, an important strategy in addressing micronutrient malnutrition through agronomic biofortification.

In parallel, soil preparation methods play a critical role in shaping the soil environment and influencing nutrient dynamics, root development, and, ultimately, crop productivity and quality [30]. Tillage practices such as plowing and cultivator affect key soil properties, including moisture retention, bulk density, and nutrient availability, all of which can impact the plant’s ability to absorb and accumulate minerals in the grain [31]. For instance, reduced or conservation tillage may improve water retention and microbial activity, while conventional plowing can enhance early root establishment, but may lead to nutrient leaching or carbon loss if not managed properly [32]. Although much research has focused on the environmental impacts of tillage, such as greenhouse gas emissions and soil degradation, less attention has been paid to how different tillage intensities directly affect grain nutritional composition and mineral enrichment, particularly in the context of agronomic biofortification strategies. Therefore, a comprehensive understanding of the interaction between soil tillage methods and foliar nutrient application is essential for optimizing the nutritional quality and mineral composition of winter barley. This study is guided by the hypothesis that the targeted application of foliar nutrients, combined with appropriate soil tillage practices, can significantly enhance grain nutritional traits, particularly beta-glucan content and mineral accumulation in winter barley. Based on this hypothesis, the objective of the study was to assess the effects of foliar nutrient supply and soil tillage methods on the grain nutritional composition and mineral content of winter barley.

2. Materials and Methods

2.1. Description of Experimental Site

The open field experiment was conducted during the winter cropping seasons of 2023 and 2024 at the Agronomy Department’s experimental plot within the Hungarian University of Agriculture and Life Sciences, situated in Gödöllő, northeast of Budapest, Hungary. The site is positioned at approximately 47°36′0″ N latitude and 19°22′0.12″ E longitude, with an elevation of 207 m (690 feet) above sea level. Prior to the establishment of the experimental crop, sunflower served as the preceding (force) crop. The soil at the location is classified as sandy loam. Throughout the study periods, data on the average temperature, precipitation, and relative humidity were recorded (Figure S1).

2.2. Experimental Design, Treatments, and Procedure

The field experiment was conducted using a split-plot design within a randomized complete block layout. Two main factors were evaluated: soil tillage method (plowing and cultivator) and nutrient treatment (control, bio-cereal, bio-algae, and a MgSMnZn blend). Each treatment was replicated three times to ensure consistency and reliability of the results. Soil tillage methods were assigned to the main plots, while nutrient treatments were applied to subplots. Each subplot measured 5 m by 6.2 m, covering an area of 31 square meters. To minimize cross-treatment interference, a 1 m buffer was maintained between plots, and blocks were separated by 2 m to ensure uniform spacing. Plowing was performed to a depth of 30 cm using a moldboard plow. This conventional tillage method fully inverted the soil, effectively burying crop residues and loosening the soil to enhance root growth and water infiltration. In contrast, the cultivator treatment used a chisel-type cultivator to a depth of 28 cm. This reduced tillage method loosened the soil without full inversion, allowing some surface residues to remain. As a result, it caused less soil disturbance compared to plowing. Both tillage treatments were followed by surface rolling to create a uniform seedbed and promote good soil-to-seed contact.

Initial land preparation was carried out using a tractor, following the respective tillage protocols. Before sowing, soil tests showed naturally available phosphorus and potassium levels of 111.1 mg kg⁻¹ and 119.9 mg kg⁻¹, respectively, during the first growing season, and 207.4 mg kg⁻¹ and 206.79 mg kg⁻¹ in the second. Details of the nutrient formulations used in the treatments are provided in Table S1. Winter barley seeds (KH TARNA variety) were sown in early October at the recommended seeding rate of 190 kg ha⁻¹, with a row spacing of 12 cm. In the spring, nitrogen fertilizer product was top-dressed at a rate of 200 kg ha⁻¹. Nutrient treatments were applied via foliar spraying at the stem elongation stage, based on the manufacturer’s recommended dosages (Table S1). Weed control was effectively managed using Granstar Super 50 SX herbicide, applied at the recommended rate of 50 g ha⁻¹ to maintain a clean field environment. To ensure effective protection of the barley crop against fungal diseases and insect pests, appropriate plant protection measures were applied before the nutrient treatment was applied in the springtime. A fungicide, Teson (containing 250 g/L of tebuconazole), was applied at a rate of 1 L ha⁻¹ to control foliar fungal infections. Additionally, to manage insect pests, the insecticide Karate Zeon 5 CS (containing 50 g/L of lambda-cyhalothrin) was applied at a rate of 0.2 L ha⁻¹. The crop was harvested at physiological maturity in mid-July, marking the completion of a carefully planned and executed cultivation process.

2.3. Grain Quality Analysis

After the crop was harvested from each plot using a combine harvester, the harvested grain was then separated from the straw using a grain separator. Then the grain sample was prepared uniformly from each treatment. Winter barley quality parameters such as Protein (%) and moisture (%) content were determined using a grain analyzer (Mininfra-2000T) in the agronomy department laboratory at MATE university. Clean barley samples were placed in a sample cell (cuvette) and inserted into the grain analyzer. The protein and moisture content of the samples were then read from the analyzer and recorded.

Other winter barley quality parameters, such as the content of β-glucan, starch, crude fat, and crude ash, as well as grain mineral concentrations (i.e., manganese (Mn), copper (Cu), zinc (Zn), and iron (Fe)), was assessed in the laboratory at the Agricultural Science Specialization of the MATE University Laboratory Center in Kaposvár. The starch content was measured according to the (152/2009/EK 111/L) testing method, while the β-glucan content was measured using the AVL MU N07 (P-Glucan Assay Kit (Mixed Linkage)) method. The crude fat content (%) was determined using the Hexane extraction method, in accordance with the Hungarian standard MSZ 6830-19:1979 [33], while the crude ash content (%) was measured through the incineration of dried samples, according to the MSZ 5984:1992 [34] method. Additionally, the grain mineral content, including Mn, Cu, Zn, and Fe, was analyzed using the (MSZ EN ISO 6869:2001 [35]) method. The following equipment was utilized for these analyses: The Prescisa 180A Analytical Balance was employed for highly accurate sample measurements, a critical factor in quantitative analysis to minimize weighing errors. Its dust cover and adjustable leveling features further enhance its performance and usability. To maintain consistent drying conditions, the Memmert UFE 500 Drying Cabinet played a crucial role. This versatile equipment can be used for drying, sterilizing, and heating various materials, making it indispensable in diverse laboratory applications. For efficient extraction of compounds from solid samples, the FALC BE6 Soxhlet Extraction Device facilitated continuous extraction, optimizing yield while reducing manual intervention. This not only improved safety, but also enhanced the efficiency of the extraction process. Precision weighing was further supported by the OHAUS Adventurer Pro Analytical Balance, which provided multiple weighing modes, including percentage and dynamic weighing. Its compact and portable design made it adaptable to various laboratory settings, ensuring convenience and accuracy in diverse applications. For high-temperature applications, the Nabertherm P320 Glow Furnace was employed for sintering and melting materials. This furnace is designed to enhance energy efficiency without compromising performance, making it a reliable choice for material processing. Elemental analysis was conducted using the Solaar M6 Atomic Absorption Spectrophotometer, an essential instrument for detecting trace elements in environmental and quality control assessments. Its ability to deliver rapid results improved laboratory throughput and efficiency.

2.4. Statistical Data Analysis

Before conducting statistical analysis, the data were evaluated to ensure they met the necessary assumptions for valid interpretation. The normality of the data distribution was assessed using the Shapiro–Wilk test [36], along with examination of skewness and kurtosis [37], which confirmed that the studied traits adhered to the assumption of normality, thus validating the subsequent analyses. Additionally, the homogeneity of variances across treatments was examined using Levene’s test, ensuring consistent variance among groups. Following the confirmation of these statistical assumptions, the data were analyzed using the General Linear Model (GLM) approach for Analysis of Variance (ANOVA). Statistical analyses were carried out using R software version 4.3.0, ‘doe bioresearch package’, providing a robust framework for data exploration and inference. For post hoc analysis, Tukey’s Honest Significant Difference (HSD) test was employed to identify significant differences among treatment means at a 5% significance level (p < 0.05). To enhance clarity and effectively communicate the results, data visualizations and graphical representations were generated using Microsoft Excel.

3. Results

3.1. Effect of Nutrient and Tillage on Winter Barley β-Glucan Across Years

A statistically significant difference in the β-glucan content of winter barley was observed with respect to nutrient treatment. In contrast, soil tillage treatment did not have a significant effect on β-glucan content. Additionally, the growing year, treated as a random factor, exerted a significant influence on β-glucan levels (

Table 1. Analysis of Variance (ANOVA) p-values for the effects of nutrient treatment and soil tillage on the grain nutritional composition of winter barley across two growing years.

Source of Variation	β-Glucan (g/100 g)	Starch (%)	Protein (%)	Moisture (%)	Crude Fat (%)	Crude Ash (%)
Tillage (T)	0.3987583 ns	0.1841464 ns	0.89325 ns	0.5528798 ns	0.040984 *	0.4795 ns
Nutrient (N)	0.0001811 ***	6.797 × 10−5 ***	0.13073 ns	0.0005514 ***	0.011969 *	5.381 × 10−9 ***
Year (Y)	<2.2 × 10−16 ***	<2.2 × 10−16 ***	<2.2 × 10−16 ***	4.646 × 10−11 ***	<2.2 × 10−16 ***	<2.2 × 10−16 ***
T × N	0.0452424 *	0.3047401 ns	0.02354 *	0.0269202 *	3.733 × 10−5 ***	0.0401 *
T × Y	0.2411686 ns	0.0048194 **	0.02831 *	6.312 × 10−8 ***	0.768490 ns	1.0000 ns
N × Y	0.0048579 **	0.0008103 ***	0.16290 ns	0.3064728 ns	6.343 × 10−7 ***	1.790 × 10−5 ***
T × N × Y	0.9933526 ns	0.8669421 ns	0.22096 ns	0.3565744 ns	0.223370 ns	3.657 × 10−7 ***

Note: p < 0.05 (*), p < 0.01 (**), p < 0.001 (***); ns = not significant.

). Post hoc comparisons using Tukey’s HSD test (

Table 2. Mean and standard deviation of β-glucan, starch, protein, and moisture contents in winter barley across nutrients, tillage treatments, and growing years.

Treatments	Studied Parameters
	β-Glucan (g/100 g)	Starch (%)	Protein (%)	Moisture (%)
Nutrient
Control	3.3558 ± 0.57821 b	50.708 ± 2.0052 b	11.1025 ± 1.99404 a	12.525 ± 0.4384 b
Bio-cereal	3.6133 ± 0.55068 a	51.633 ± 1.6906 a	11.0883 ± 2.15677 a	12.692 ± 0.4582 ab
Bio-algae	3.5800 ± 0.69909 a	51.175 ± 1.5897 ab	11.3567 ± 2.10229 a	12.683 ± 0.539 ab
MgMnSZn blend	3.5083 ± 0.54375 ab	51.508 ± 1.2664 a	10.9442 ± 1.82866 a	12.908 ± 0.5212 a
Tillage
Plowing	3.4962 ± 0.57141 a	51.354 ± 1.4561 a	11.1146 ± 2.13644 a	12.683 ± 0.5230 a
Cultivator	3.5325 ± 0.62746 a	51.158 ± 1.8835 a	11.1313 ± 1.88693 a	12.721 ± 0.4890 a
Year
1	3.0079 ± 0.24323 b	52.404 ± 1.0068 a	9.3667 ± 0.43996 b	12.475 ± 0.4961 b
2	4.0208 ± 0.37615 a	50.108 ± 1.4146 b	12.8792 ± 1.2945 a	12.929 ± 0.4033 a
CV	7.31	1.72	6.69	2.98

Where CV = Coefficient of Variation; different letters indicate a significant difference between treatments at p < 0.05. The symbol ± represents the standard deviation of the mean.

) indicated that the bio-cereal nutrient treatment produced the highest β-glucan content, closely followed by the bio-algae nutrient treatment; these two treatments did not differ significantly from each other. The control treatment exhibited a significantly lower β-glucan content. Interestingly, the MgMnSZn nutrient blend produced a β-glucan content that was statistically comparable to that produced by both the bio-cereal and bio-algae treatments, although its numerical value was slightly lower. However, the MgMnSZn blend treatment also did not differ significantly from the control. Regarding the growing year, the second year produced the highest β-glucan content, whereas the first year showed comparatively lower levels.

3.1.1. Synergistic Effects of Tillage and Nutrient Treatments on β-Glucan Content in Winter Barley

The interaction between nutrient treatment and soil tillage had a statistically significant effect on the β-glucan content of winter barley, with notable differences observed across treatment combinations (Table 1). The highest β-glucan content was recorded under the interaction of cultivator tillage with the bio-cereal nutrient treatment, averaging 3.68 g/100 g, which was significantly greater than that for all other combinations. This was closely followed by the interaction of cultivator tillage with the bio-algae treatment (3.67 g/100 g), which also resulted in elevated β-glucan levels that did not differ significantly from those produced under the cultivator–bio-cereal treatment (Figure 1).

In contrast, plowing-based treatments generally resulted in lower β-glucan contents. Specifically, the interactions of plowing with the MgMnZnS nutrient blend (3.55 g/100 g) and with the bio-cereal treatment (3.54 g/100 g) exhibited a noticeable reduction compared to the cultivator-based treatments, though their values remained significantly higher than those observed in the control groups. The lowest β-glucan contents were found under the control treatments, with the plowing–control and cultivator–control combinations yielding contents of 3.41 g/100 g and 3.31 g/100 g, respectively (Figure 1).

3.1.2. Interaction Effects of Nutrient Treatment and Growing Year on β-Glucan Content in Winter Barley

The interaction effect between nutrient treatments and growing years on the β-glucan content in winter barley showed significant variations (Table 1). The highest β-glucan content was observed in the interaction of the bio-algae treatment with the second growing year, with an average value of 4.17 g/100 g. This value was significantly higher than that for all other treatments. The combination of the MgMnZnS nutrient blend with the second growing year followed closely, with an average of 4.02 g/100 g, showing a similarly elevated β-glucan level, though slightly lower than that for the bio-algae treatment. The bio-cereal treatment with the second growing year also exhibited a high β-glucan content (3.99 g/100 g), with values that were statistically similar to those produced under the combination of the MgMnZnS treatment with the second growing year. In contrast, the interaction of the control treatment with the second growing year produced a relatively high β-glucan content compared to the previous year, but it was lower than that produced under the bio-algae nutrient treatment in the second growing year (Figure 2).

In the first growing year, all treatments resulted in lower β-glucan concentrations compared to in the second year. Among these, the bio-cereal nutrient treatment with the first growing year showed an average of 3.23 g/100 g, which was the highest in the first year, but still significantly lower than that for the treatments in the second year. The blend of the MgMnZnS treatment with the first growing year, with a value of 3.00 g/100 g, and the blend of the bio-algae treatment with the first growing year (2.99 g/100 g) were statistically similar to each other, but still displayed a notable decrease in β-glucan content compared to the treatments in the second growing year. The lowest β-glucan content was observed under the control treatment in the first growing year, with an average value of 2.81 g/100 g (Figure 2).

3.2. Effect of Nutrient and Tillage on Starch Content in Winter Barley Across Growing Years

The starch content of winter barley showed significant differences according to the main effect of nutrient treatment and to the growing year as a random factor. However, the main effect of tillage treatment did not produce significant differences in the starch content of the winter barley (Table 1). According to the mean results shown in Table 2, the bio-cereal treatment produced the highest starch content, which was statistically comparable to that under the MgMnZnS blend treatment. In the same way, the bio-algae treatment produced a statistically similar value to that for both the bio-cereal treatment and the MgMnZnS blend treatment. The control treatment exhibited the lowest starch content, showing a statistically significant difference from that for all the other nutrient treatments. Additionally, the starch content varied significantly between growing years, with higher levels recorded in the first year and lower levels observed in the second year.

3.2.1. Nutrient × Growing Year Interaction Effect on Starch Content in Winter Barley

The interaction between nutrient treatments and growing year on the starch content in winter barley is presented in Table 1. In the first growing year, all nutrient treatments, including the control, resulted in the highest starch content, with no statistically significant differences observed among them (Figure 3). In contrast, the second growing year showed a noticeable reduction in starch content across all treatments. The MgMnZnS blend treatment displayed a starch content of 50.80%, significantly lower than that in the first year. Similarly, the bio-cereal treatment in the second year exhibited a starch content of 50.33%, while the bio-algae and control treatments recorded 50.13% and 49.17%, respectively. These values were also statistically different from those in the first growing year. The control treatment in the second year exhibited the lowest starch content, at 49.17%, which was significantly different from that for all other treatments (Figure 3).

3.2.2. Effects of Tillage and Growing Year on Starch Content in Winter Barley

The interplay between tillage method and growing year exerted a discernible influence on the starch content of winter barley (Table 1). In the first year of cultivation, the application of a cultivator tillage method resulted in a starch content of 52.52%, marginally surpassing the 52.29% observed under the plowing tillage method. However, this trend shifted in the subsequent year. While the cultivator treatment led to a decrease in starch content to 49.8%, plowing, despite also showing a reduction, maintained a higher starch content of 50.42% (Figure 4).

3.3. Effects of Nutrient and Tillage Treatments on Protein and Moisture Content of Winter Barley Across Growing Years

The main effects of the nutrient and tillage treatments did not significantly influence the protein content of winter barley. However, the growing year showed a significant impact (Table 1). Specifically, the second growing season yielded the highest mean protein content (12.88%), while the first season resulted in the lowest (9.37%) (Table 2). Regarding moisture content, significant differences were observed for both nutrient treatment and growing year, but not for tillage treatment (Table 1). The highest moisture content (12.91%) was recorded under the MgMnSZn blend nutrient treatment. Statistically similar moisture levels were found with bio-cereal (12.69%) and bio-algae (12.68%) treatments. Conversely, the control treatment exhibited the lowest moisture content (12.53%). With regard to the growing year, the maximum (12.93%) and minimum (12.47%) moisture contents were recorded in the second and the first growing year, respectively (Table 2).

3.3.1. Interaction Effects of Tillage and Nutrient Treatments on Protein Content in Winter Barley

The interaction between tillage methods and nutrient treatments significantly influenced the winter barley protein content (Table 1). Under cultivator tillage, the bio-algae nutrient treatment yielded the highest protein content, at 11.51%, significantly outperforming the MgMnZnS blend nutrient treatment, which yielded the lowest content, at 10.63%. The remaining treatments, including bio-cereal and the control, resulted in statistically similar results, clustering around 11.2%. Conversely, under plowing tillage, the performance of the nutrient treatments was more uniform. While the results for the MgMnZnS blend nutrient treatment slightly exceeded those for the bio-algae treatment, both, along with the bio-cereal treatment and the control, produced statistically indistinguishable results, ranging from 10.93 to 11.26% (Figure 5).

3.4. Effect of Nutrient and Tillage Treatment on Crude Fat and Crude Ash Content of Winter Barley

Statistically significant effects of nutrient treatments and tillage methods were observed on both the crude fat and crude ash contents in winter barley (Table 1). According to the mean values presented in

Table 3. Mean and standard deviation of crude fat (%) and crude ash (%) content in winter barley across nutrient and tillage treatments.

Treatments	Studied Parameters
	Crude Fat (%)	Crude Ash (%)
Nutrient
Control	2.083 ± 0.1978 b	2.408 ± 0.1461 a
Bio-cereal	2.083 ± 2.083 b	2.317 ± 0.1159 b
Bio-algae	2.100 ± 0.2484 ab	2.408 ± 0.1826 a
MgMnSZn blend	2.142 ± 0. 2852 a	2.417 ± 0.1748 a
Tillage
Plowing	2.117 ± 0.2338 a	2.392 ± 0. 1508 a
Cultivator	2.088 ± 0.2313 b	2.383 ± 0. 1712 a
CV	4.03	2.95

Where CV = Coefficient of Variation; different letters indicate a significant difference between treatments at p < 0.05. The symbol ± represents the standard deviation of the mean.

, the MgMnSZn blend nutrient treatment resulted in the highest crude fat content, significantly greater than that observed under the control and bio-cereal treatments. In terms of crude ash content, all nutrient treatments, except for bio-cereal, exhibited statistically similar and comparatively higher values, including the control. With respect to tillage methods, plowing yielded a marginally higher crude fat content than the cultivator method. However, no significant differences were detected between tillage treatments for crude ash content, as both methods produced comparable results (Table 3).

3.5. Effect of Nutrient and Tillage on Grain Micronutrient Content of Winter Barley Across Growing Years

Significant differences was observed in the grain micronutrient contents of winter barley according to the nutrient treatment, the tillage type, and the growing year as random factor (

Table 4. Analysis of Variance (ANOVA) p-values for the effects of nutrient treatments and soil tillage on the micronutrient composition of winter barley grains across the two growing seasons.

Source of Variation	Mn (mg/kg)	Cu (mg/kg)	Zn (mg/kg)	Fe (mg/kg)
Tillage (T)	0.071601 ns	0.16751 ns	1.254 × 10−5 ***	1.361 × 10−6 ***
Nutrient (N)	1.068 × 10−6 ***	0.01324 *	2.122 × 10−6 ***	0.004253 **
Year (Y)	0.000405 ***	<2 × 10−16 ***	0.0017426 **	<2.2 × 10−16 ***
T × N	0.489187 ns	0.47833 ns	0.0230934 *	0.020387 *
T × Y	0.754595 ns	0.03279 *	5.671 × 10−5 ***	0.466580 ns
N × Y	5.983 × 10−7 ***	0.09140 ns	3.314 × 10−5 ***	6.154 × 10−5 ***
T × N × Y	0.328556 ns	0.01096 *	0.0001064 ***	0.204462 ns

Note: p < 0.05 (*), p < 0.01 (**), p < 0.001 (***); ns = not significant. Mn = manganese, Cu = copper, Zn = zinc, Fe = iron.

).

The manganese content in the winter barley was significantly influenced by the nutrient treatment and growing season, while soil tillage had no significant effect (Table 4). Among the nutrient treatments, the bio-algae treatment resulted in the highest manganese concentration, followed closely by the bio-cereal treatment, with both exhibiting statistically similar values. The lowest manganese content was recorded for the control treatment, which was statistically comparable to that for the MgMnSZn blend. Regarding seasonal variation, the manganese content was higher in the first growing year compared to the second (

Table 5. Mean and standard deviation of Mn, Cu, Zn, and Fe contents (mg/kg) in winter barley across nutrient treatments, tillage methods, and growing years.

Treatments	Studied Parameters
	Mn (mg/kg)	Cu (mg/kg)	Zn (mg/kg)	Fe (mg/kg)
Nutrient
Control	13.058 ± 1.5594 b	4.1908 ± 0.34518 b	24.458 ± 1.6744 ab	44.533 ± 3.0629 a
Bio-cereal	13.800 ± 0.8596 a	4.1925 ± 0.45456 b	22.942 ± 2.2815 c	43.267 ± 4.3344 ab
Bio-algae	13.967 ± 1.0526 a	4.2442 ± 0.36356 ab	23.842 ± 1.474 b	42.725 ± 2.6242 b
MgMnSZn blend	13.175 ± 1.0109 b	4.3817 ± 0.54463 a	24.733 ± 2.0021 a	42.383 ± 4.7322 b
Tillage
Plowing	13.621 ± 1.1904 a	4.2846 ± 0.42819 a	23.446 ± 1.8353 b	42.112 ± 3.7752 b
Cultivator	13.379 ± 1.2143 a	4.2200 ± 0.44379 a	24.542 ± 1.9944 a	44.342 ± 3.5920 a
Year
1	13.742 ± 1.2480 a	3.9371 ± 0.22700 b	24.379 ± 1.7683 a	41.096 ± 3.7536 b
2	13.258 ± 1.1160 b	4.5675 ± 0.36219 a	23.608 ± 2.1277 b	45.358 ± 3.8384 a
CV	5.91	6.56	6.02	6.10

CV = Coefficient of Variation; different letters indicate a significant difference between treatments at p < 0.05. Mn = manganese, Cu = copper, Zn = zinc, Fe = iron. The symbol ± represents the standard deviation of the mean.

).

For copper content, both the nutrient treatment and the growing year had a significant impact, whereas the tillage treatment did not produce any significant differences (Table 4). The MgMnSZn blend resulted in the highest copper concentration, followed by the bio-algae treatment, with no significant difference between them. The bio-cereal and control treatments exhibited the lowest copper levels, which were also statistically similar. Seasonally, the copper content was higher in the second growing year than in the first (Table 5).

The zinc content was significantly affected by the nutrient treatment, tillage, and growing year (Table 4). The MgMnSZn treatment produced the highest zinc concentration, followed by the control and bio-algae treatments, which were statistically similar. The lowest zinc content was observed under the bio-cereal treatment. With respect to tillage, the cultivator method resulted in a higher zinc content compared to plowing. Additionally, the first growing year showed greater zinc accumulation than the second (Table 5).

The iron content was significantly influenced by the nutrient treatment, tillage, and growing year, as indicated by the ANOVA results in Table 4. The highest iron content was observed under the control treatment, followed by the bio-cereal treatment, both of which were statistically similar. In contrast, the bio-algae and MgMnSZn treatments produced lower but statistically similar iron concentrations. Similarly to zinc, a higher iron content was associated with the cultivator tillage method, while plowing resulted in the lowest values. Regarding seasonal effects, the iron content was greater in the second growing year compared to the first (Table 5).

3.5.1. Interaction Effect of Nutrient Supply and Growing Year on Mn, Zn, and Fe Concentrations in Winter Barley

The interaction between nutrient treatments and growing year had a significant effect on the manganese (Mn), zinc (Zn), and iron (Fe) contents in winter barley (Table 4). For manganese, the highest concentrations were observed in plants treated with the bio-algae nutrient during the second growing year. This was followed closely by the control treatment in the first year and the bio-cereal treatments across both years, all of which showed no statistically significant differences in Mn content. The MgMnZnS blend applied in the first growing year also resulted in relatively high Mn levels, statistically comparable to those for the aforementioned treatments. In contrast, significantly lower Mn concentrations were observed in the second growing year for both the MgMnZnS blend and the control treatment (

Table 6. Interaction effect of nutrient treatment and growing year on manganese (Mn), zinc (Zn) and iron (Fe) contents in winter barley.

Nutrient Treatment	Mn (mg/kg)		Zn (mg/kg)		Fe (mg/kg)
	Year 1	Year 2	Year 1	Year 2	Year 1	Year 2
Control	13.900 a	12.216 c	24.533 ab	24.383 b	42.166 c	46.9 a
Bio-cereal	13.733 a	13.866 a	22.566 c	23.316 bc	41.033 cd	45.5 ab
Bio-algae	13.800 a	14.133 a	24.416 b	23.266 bc	42.266 c	43.183 bc
MgMnZnS blend	13.533 ab	12.816 bc	26 a	23.466 bc	38.916 d	45.85 ab
CV (%)	5.91		6.02		6.10

Different letters indicate a significant difference between treatments at p < 0.05. The symbol ± represents the standard deviation of the mean., Mn = manganese, Zn = zinc, Fe = iron.

).

The zinc content was also significantly influenced by the interaction between nutrient treatment and growing year. The MgMnZnS treatment in the first year produced the highest Zn concentration, statistically similar to that of the control treatment in the same year. Moderately high Zn levels were also recorded for the bio-algae and control treatments in the second year, which did not differ significantly from those for the control in the first year. In the second growing year, Zn levels under the MgMnZnS, bio-cereal, and bio-algae treatments were statistically similar, but were significantly lower than those observed in the first-year MgMnZnS treatment. The lowest Zn concentration was found for the bio-cereal treatment during the first year, which was significantly different from all other treatment combinations (Table 6).

The interaction of nutrient treatment and growing year also significantly affected the iron content. The highest Fe levels were recorded for the control treatment during the second year, with statistically similar values observed under the MgMnZnS and bio-cereal treatments in the same season. The bio-algae treatment in the second year, along with the bio-algae and control treatments in the first year, yielded moderately high Fe contents, all of which were statistically comparable. The bio-cereal treatment in the first year produced a slightly lower Fe content. The lowest Fe concentration was recorded for the MgMnZnS treatment during the first year, significantly differing from that under the other treatment combinations (Table 6).

3.5.2. Effect of Interaction Between Tillage and Growing Year on Copper and Zinc Accumulation in Winter Barley

The interaction between tillage method and growing year significantly influenced the copper (Cu) content of winter barley (Table 4). In the second growing year, plowing resulted in the highest Cu content. This was statistically similar to the Cu level obtained with a cultivator in the same year. However, in the first growing year, both plowing and cultivator tillage resulted in a significantly lower Cu content compared to in the second year. There was no significant difference between plowing and cultivation within the first year (

Table 7. Interaction effect of tillage and growing year on copper (Cu) and zinc (Zn) contents in winter barley.

Tillage Treatment	Cu (mg/kg)		Zn (mg/kg)
	Year 1	Year 2	Year 1	Year 2
Plowing	3.955 b	4.65 a	24.3333 a	22.55833 b
Cultivator	3.92 b	4.485 a	24.425 a	24.65833 a
CV (%)	6.56		6.02

Different letters indicate a significant difference between treatments at p < 0.05. Cu = copper, Zn = zinc.

).

Similarly, the interaction between tillage method and growing year significantly influenced the zinc (Zn) content in winter barley (Table 4). Cultivator tillage in the second growing year resulted in the highest Zn content. This was statistically similar to that produced under cultivator tillage in the first year and plowing in the first year. However, plowing in the second year resulted in a significantly lower Zn content compared to all other treatment combinations (Table 7).

3.5.3. The Combined Effect of Nutrient Treatment, Tillage Type, and Growing Year on the Copper Levels in Winter Barley

The interaction among nutrient treatment, tillage method, and growing year had a significant effect on the copper (Cu) content in winter barley (Table 4). The highest Cu concentration was observed under cultivator tillage combined with the MgMnZnS nutrient blend in the second growing year, measuring 4.80 mg/kg. This value was statistically comparable to that obtained under plowing combined with the bio-algae treatment (4.70 mg/kg), plowing combined with the MgMnZnS blend (4.70 mg/kg), and plowing combined with the bio-cereal treatment (4.66 mg/kg) during the same year. Plowing with the control treatment (4.55 mg/kg) and cultivator tillage with the bio-cereal treatment (4.46 mg/kg) in the second growing year also showed moderately high Cu concentrations.

In the first growing year, significantly lower copper (Cu) concentrations were observed across all treatment combinations compared to those in the second year. Specifically, plowing with the MgMnZnS blend (4.12 mg/kg), cultivator tillage with the bio-algae treatment (4.06 mg/kg), plowing with the bio-algae treatment (3.98 mg/kg), cultivator tillage with the control treatment (3.95 mg/kg), cultivator tillage with the MgMnZnS blend treatment (3.91 mg/kg), cultivator tillage with the bio-cereal treatment (3.90 mg/kg), plowing with the control treatment (3.84 mg/kg), and plowing with the bio-cereal treatment (3.74 mg/kg) all exhibited comparably low Cu levels. The results for these treatments did not differ significantly from one another (Figure 6).

3.5.4. The Synergetic Effect of Nutrient Treatment and Tillage Type on Zinc (Zn) Levels in Winter Barley

The interaction between nutrient treatment and tillage method had a significant effect on the zinc (Zn) content in winter barley (Table 4). As illustrated in Figure 7, the highest Zn concentration was recorded under the combination of cultivator tillage and the control treatment (24.98 mg/kg). This value was statistically similar to those observed with plowing combined with the MgMnZnS blend (24.75 mg/kg) and cultivator tillage combined with the same nutrient treatment (24.72 mg/kg). Moderately high Zn levels were also found for cultivator tillage with the bio-algae treatment (24.48 mg/kg), cultivator tillage with the bio-cereal treatment (23.98 mg/kg), and plowing with the control treatment (23.93 mg/kg), all of which were statistically comparable to the highest group. A significantly lower Zn concentration was recorded for plowing combined with the bio-algae treatment (23.20 mg/kg), while the lowest Zn content was observed for plowing combined with the bio-cereal treatment (21.90 mg/kg), which differed significantly from that for all other treatments.

3.5.5. The Interactive Effects of Nutrient Management, Tillage Practice, and Growing Season on Zinc (Zn) Concentration in Winter Barley

The zinc (Zn) content in winter barley was significantly influenced by the interaction among nutrient treatments, tillage methods, and growing years (Table 4). The highest Zn concentrations were recorded under both the cultivator and plowing tillage systems when combined with the MgMnZnS blend nutrient treatment during the first growing year, each reaching 26.00 mg/kg. Comparable levels were observed for cultivator tillage combined with the control treatment (25.83 mg/kg) and cultivator tillage combined with the bio-cereal treatment (25.57 mg/kg) in the second year, both statistically similar to the highest values. Additionally, cultivator tillage combined with the bio-algae treatment in the first year (25.17 mg/kg) and plowing combined with the control treatment in the first year (24.93 mg/kg) produced a moderately high Zn content, also showing no significant difference from the top-performing combinations (Figure 8).

Cultivator tillage combined with the control treatment in the first year (24.13 mg/kg), cultivator tillage with the bio-algae treatment in the second year (23.80 mg/kg), plowing with the bio-algae treatment in the first year (23.67 mg/kg), and plowing with the MgMnZnS blend treatment in the second year (23.50 mg/kg) produced statistically similar Zn contents, though significantly lower than those for the highest-performing combinations. Similarly, cultivator tillage combined with the MgMnZnS blend treatment in the second year (23.43 mg/kg), plowing combined with the control treatment in the second year (22.93 mg/kg), and both plowing combined with the bio-algae treatment and plowing combined with the bio-cereal treatment in the first year (22.73 mg/kg each) produced Zn levels that were statistically similar, but markedly lower than those for the preceding group. Cultivator tillage combined with the bio-cereal treatment in the first year (22.40 mg/kg) presented a further reduction in Zn content. The lowest Zn concentration was observed under plowing combined with the bio-cereal treatment during the second growing year (21.07 mg/kg), which was significantly different from that for all other treatment combinations (Figure 8).

3.5.6. The Synergistic Effect of Nutrient Treatment and Tillage Type on the Iron (Fe) Content in Winter Barley

The iron (Fe) content in winter barley was significantly influenced by the interaction between nutrient treatment and tillage method (Table 4). Cultivator tillage combined with the bio-cereal treatment resulted in the highest Fe content (45.50 mg/kg), statistically equivalent to that under the control treatment combined with cultivator tillage (44.85 mg/kg). Plowing combined with the control treatment yielded a content of 44.22 mg/kg, which was statistically similar to that under both of the aforementioned treatments and under cultivator tillage combined with the bio-algae treatment (43.58 mg/kg). Cultivator tillage combined with the MgMnZnS blend treatment produced an Fe content of 43.43 mg/kg. Plowing combined with the bio-algae, MgMnZnS blend, and bio-cereal treatment resulted in the lowest Fe contents, with values of 41.87 mg/kg, 41.33 mg/kg, and 41.03 mg/kg, respectively (Figure 9).

4. Discussions

4.1. Influence of Nutrient Treatment, Tillage Type, and Growing Year on β-Glucan Levels in Winter Barley

The analysis of β-glucan concentration in relation to the imposed factors, such as foliar nutrients and growing year, showed clear differences in our study. The observed increases in β-glucan content with the bio-cereal and bio-algae nutrient treatments (Table 2) indicates the potential of these foliar biological nutrients to enhance the quality of barley. Compared to the control treatment, the bio-cereal and bio-algae nutrient treatments increased the β-glucan content of winter barley by 7.67% and 6.68%, respectively. These resulting increases might be attributable to the unique characteristics of those foliar nutrient treatments, which may have modern chelating agents and bioactive compounds which could enable the nutrients to be directly absorbed by the plants, ultimately leading to an enhanced β-glucan concentration in the crop. In addition to this, these biological nutrient treatments contain different nutrient compositions, which might contribute to enhancing the levels of beta glucan. Our results are in line with reports in [38,39] that the amount of β-glucan in barley grains rose when high nitrogen levels were applied. Additionally, applying nitrogen fertilization together with selenium fertilization significantly increased the content of beta glucan in oats [40,41]. This indicates that the application of different nutrients can increase the beta glucan content in barley. However, the current findings are in contrast to those reported in [42], which concluded that the β-glucan content in barley and wheat grains was primarily influenced by weather conditions rather than fertilization practices. The significant differences observed in the β-glucan content of winter barley according to the growing season reveal the influence of environmental factors on this quality trait. The higher β-glucan content observed in the second growing year (Table 2) may be attributed to variations in environmental conditions, particularly temperature and rainfall patterns. These climatic factors can influence plant physiological processes, potentially enhancing growth and development, which, in turn, may contribute to an increased β-glucan accumulation in barley grains [43]. This finding demonstrates the importance of considering environmental variability when applying agronomic practices to increase the quality of a crop. Furthermore, the current results are supported by [44], which concluded that the content and molecular weight of β-glucan in oats affected by the environment. Moreover, during the grain filling and maturation stages, increased rainfall and lower temperatures may contribute to a reduction in the β-glucan content in barley and oat crops [45].

Although the tillage treatment alone did not result in a significant difference in β-glucan content (Table 2), it had a synergistic effect with nutrient treatments, thereby influencing the β-glucan content in winter barley. As shown in Figure 1, the combination of cultivator tillage with the bio-cereal and cultivator tillage with the bio-algae treatment resulted in the highest β-glucan content. Compared to cultivator tillage with the control treatment, these combined treatments led to a significant increase in β-glucan content by 11.39% and 10.94%, respectively. In contrast to plowing combined with the control treatment, plowing with the MgMnZnS blend, bio-cereal, and bio-algae treatments increased the β-glucan content by 4.11%, 4.06%, and 2.53%, respectively. This suggests that the combined impact of tillage and nutrient treatments can work synergistically to boost barley’s nutritional profile. The synergy between tillage and foliar nutrient applications likely involves multiple factors, such as improved nutrient availability, better soil structure, and enhanced metabolic processes in the barley plants. Tillage can influence soil water content, aeration, and structure, thereby improving the uptake of nutrients, while foliar nutrient treatments may directly supply bioavailable compounds that enhance the plant’s ability to produce β-glucan.

4.2. The Impact of the Interaction Between Nutrient and Growing Year on Winter Barley Starch Content

The evaluation of starch content in our study showed notable variations according to interactions between the experimental variables of nutrient treatment and growing year (Figure 3). In the first growing year, there was no discernible difference in the amount of starch between treatments; however, in the second year, the starch levels under all nutrient treatments showed a significant decrease. This shows that the way in which nutrient treatments alter the starch content may be influenced by environmental factors or soil conditions that change from one growing year to the next [46]. During the first growing year, the starch content was comparatively similar in all nutrient treatments, with values greater than 52% (Figure 3). The fact that these treatments did not significantly differ from one another indicates that, under the conditions of the first growing year, all of the nutrient treatments were equally effective in promoting the synthesis of starch in winter barley. This may indicate that these nutrients proved to be equally advantageous, or that their effects on starch production were unaffected by the particular growth circumstances of that year. However, the reduction in starch content shown in the second growing year implies that the plant’s capacity to efficiently use the delivered nutrients may have been impacted by environmental variables like variations in temperature, precipitation, or soil nutrient availability [47]. This means that the reduced availability of vital nutrients, stressors that impacted the barley’s metabolism, or a possible nutritional imbalance may have hampered the synthesis of starch [48]. It is possible that the barley was more vulnerable to these unfavorable circumstances in the absence of the additional nutrients, which resulted in lower starch production, as evidenced by the control treatment’s most noticeable loss, which dropped below 50% (Figure 3). The observed significant differences under the control treatment in the second year further affirm that barley development under varying environmental conditions depends on the addition on nutrients [49]. Given that the control treatment produced the lowest starch content, this could indicate how crucial good nutrient management is to maintaining maximum crop nutritional quality.

4.3. The Effect of Nutrient Treatment, Tillage Type, and Growing Year on the Grain Micronutrient Content of Winter Barley

The micronutrient content observed in our study revealed both positive and negative effects in response to different nutrient treatments, with the control group serving as the baseline (Table 5). A detailed analysis of the manganese (Mn) content indicated (Table 5) that the nutrient treatments had a favorable impact on Mn levels, with both the bio-algae and bio-cereal treatments producing significant increases. Specifically, the bio-algae treatment resulted in a 6.96% increase in Mn content, while the bio-cereal treatment showed a 5.68% increase. In contrast, the MgMnZnS blend only produced a marginal increase of 0.09%. Interestingly, the highest Mn content was found under the bio-algae treatment, despite its lack of direct Mn delivery [50]. This outcome suggests that bio-algae may enhance the uptake and bioavailability of Mn within the plant or soil, even in the absence of direct Mn addition. Algae-based nutrients are known to contain growth-promoting substances such as phytohormones and trace elements [51], which could improve the plant’s ability to absorb essential nutrients, including Mn.

In the case of the bio-cereal treatment, Mn was directly supplied as a component, and its presence in the plant was anticipated. However, the higher Mn content observed under the bio-cereal treatment compared to under the MgMnZnS blend treatment suggests that the form of Mn found in bio-cereal may be more readily available for plant uptake. Furthermore, the chelating agent in bio-cereal could potentially facilitate more efficient Mn uptake and transport within the plant. Although the MgMnZnS blend contains Mn, the lower levels of Mn observed in plants treated with this blend may be attributed to nutrient interactions or competition between Mg, Zn, and S, which could affect the absorption of Mn. Overall, the results indicate that organic treatments, such as bio-algae and bio-cereal, are more effective in enhancing Mn content compared to the synthetic MgMnZnS blend. This suggests that organic treatments may offer a superior means of improving micronutrient availability, particularly Mn, when compared to synthetic nutrient blends, which showed only a modest increase. This result is supported by [27], which reported that when sulfur, especially ammonium sulfate, is added to barley, the grain Mn concentration increases, which tells us that the application of different nutrient treatments affects the content of nutrients in grains, including manganese.

Regarding the results for zinc (Zn) content, this was found to be affected by the main and synergetic effects of nutrient treatment, tillage type, and growing year (Table 5 and Table 7). Mainly, it was negatively affected by the nutrient treatment as compared to the control treatment, with the exception of the MgMnZnS combination treatment (Table 5). The MgMnZnS blend treatment produced a slight increment, but was this was statistically similar to that under the control treatment. The reason for this might be that the uptake of Zn in plants can be influenced by the presence of other nutrients, particularly if those nutrients compete for absorption sites in the plant parts. This suggests that the individual application of Zn may increase the grain Zn concentration. With regard to tillage treatment, it was observed that a greater grain Zn content was obtained under cultivator tillage than under plowing (Table 5). The reason for this might be that cultivator tillage is slightly shallower than plowing, which may improve soil structure, nutrient redistribution and availability, soil organic matter, and crop root access. Synergistically, the winter barley’s Zn content was greatly influenced by the growing season and tillage technique (Table 7). Regardless of the growth season, cultivator tillage continuously produced increased Zn concentrations, suggesting stability in Zn uptake. Plowing in the second year, on the other hand, significantly decreased the Zn concentration, indicating a possible adverse interaction between plowing and the year’s environmental conditions. This result is consistent with findings that tillage techniques can affect the availability of nutrients in the soil, and consequently plant absorption [52,53,54]. Zinc availability may be improved by cultivator tillage, which is frequently linked to reduced soil disturbance, and may encourage a more stable soil structure and microbial activity [55]. According to [56], the variation across growing years indicates the significance of taking into account climatic conditions like temperature and rainfall, which can alter nutrient cycling and plant uptake. Future studies, maybe combining soil analysis and meteorological data, should investigate the precise environmental factors that cause the decreased Zn concentration seen with plowing in the second year.

Concerning grain iron (Fe) content, the control treatment exhibited the highest Fe concentration (Table 5), suggesting adequate indigenous soil availability for optimal uptake [57]. Bio-cereal nutrient application resulted in similar Fe levels, indicating its potential as a comparable alternative. However, the bio-algae and MgMnSZn treatments produced significantly lower Fe contents, likely due to antagonistic interactions or altered Fe solubility [58]. Tillage practices also influenced Fe levels, with cultivator tillage enhancing the Fe content (Table 5), supporting findings that reduced tillage improves nutrient availability by enhancing soil structure [59]. In contrast, plowing, which disrupts soil aggregates and increases aeration, resulted in a lower Fe content, consistent with studies showing that increased aeration can lead to Fe oxidation and precipitation [60]. Additionally, the Fe content was higher in the second year, likely influenced by environmental factors such as temperature and rainfall, which affect Fe cycling and availability.

5. Conclusions

This study revealed that the interplay of fertilizer management, tillage techniques, and environmental variability during growing seasons significantly influences the nutritional and mineral content of winter barley. The use of fertilizer treatments or tillage techniques alone did not significantly affect grain protein content; nevertheless, a notable interaction between tillage and nutrient delivery was identified, highlighting the necessity for integrated agronomic strategies.

The utilization of bio-algae and bio-cereal nutrients markedly increased the β-glucan content, especially when integrated with cultivator-based tillage. This discovery affirms the significance of biologically sourced nutrients in enhancing the dietary fiber content of barley grains. Conversely, starch accumulation exhibited no significant variation across nutritional treatments; still, all nutrient-treated plots showed elevated starch levels compared to the control, indicating a beneficial influence of food availability on carbohydrate biosynthesis.

The mineral content of barley grains indicated intricate reactions. Manganese (Mn) and copper (Cu) were predominantly affected by nutrient availability, whereas zinc (Zn) and iron (Fe) levels exhibited substantial responses to the primary effects of nutrient treatment, tillage type, and growing year. Appling a multiple-nutrient composition-based treatment did not yield additive enhancements in Fe and Zn accumulation. These data indicate that the tailored treatment of individual micronutrients may be more efficacious in augmenting specific mineral concentrations. Cultivator tillage was correlated with increased levels of Fe and Zn, suggesting its potential to enhance micronutrient density in cereal grains.

Therefore, this study emphasizes the necessity of optimizing agronomic procedures, specifically the incorporation of suitable nutrient inputs and tillage methods, to improve the nutritional quality of winter barley. These insights further the overarching objective of establishing sustainable crop management strategies that enhance both nutritional food security and human health by improving grain quality.