Biostimulant effects of poultry feather hydrolysate on wheat and soil: effects of addition rate and state

The growing need for sustainable agricultural practices has intensified interest in alternative soil amendments such as poultry feather hydrolysate (PFH), a nutrient-rich biostimulant derived from poultry industry waste. Despite the promising benefits of PFH in promoting plant growth and improving soil health, its effectiveness in soil application across different addition rates and states remains underexplored. This study assessed the effects of PFH applied on the soil surface at no, low (4 t dw ha^–1) and high (8 t dw ha^–1) addition rates in either liquid or solid states on wheat (Triticum aestivum L.) biomass growth and soil properties in a 3-month controlled pot experiment. Irrespective of the addition rate, PFH consistently increased wheat shoot and root biomass by up to 109% and 74%, respectively, with stronger cumulative effects observed over time. The high addition rate significantly increased the soil organic matter (OM) content by 20% and improved the water-holding capacity by 9%, while concurrently reducing the pH by up to 7%. In the liquid state, PFH stimulated rapid biomass growth, microbial activity and dissolved nitrogen (DN) content, whereas in the solid state it sustained microbial activity and DN content over the longer term. Despite these changes, microbial biomass and OM stabilization remained unaffected. Overall, the results demonstrate that PFH, particularly in the liquid state, acts as a readily available nutrient source that promotes wheat growth and improves soil quality, offering a practical and sustainable option for organic waste recycling and nutrient management in cereal cropping systems.

1 Introduction

Modern agricultural productivity largely relies on synthetic fertilizers to supply essential nutrients to crops (Tripathi et al., 2020). However, the growing need to enhance crop yields is increasingly being challenged by environmental stresses like salinity, drought, extreme temperatures and both organic and inorganic contaminants (Gezgincioğlu and Atici, 2023). These challenges have driven the search for alternative approaches that are more sustainable, cost-effective and environment friendly. One such promising alternative is poultry feather hydrolysate (PFH), an organic amendment derived from the enzymatic or chemical breakdown of poultry feathers, a major waste product of the poultry industry (Gupta et al., 2023). Abundant in carbon (C), nitrogen (N) and micronutrients, PFH transforms poultry waste into a resource that supports soil health and promotes plant growth, positioning it as a valuable input for sustainable crop production (Tamreihao et al., 2019). However, despite its potential, limited information is available regarding optimal application methods for PFH and its subsequent impact on plant biomass growth and soil properties.

PFH has been increasingly recognized as a non-microbial biostimulant due to its proven ability to enhance plant growth, crop yield and biomass quality (Adelere and Lateef, 2023). Studies have reported that application of PFH consistently promotes early root and leaf biomass development, which contributes to improved overall productivity (Raguraj et al., 2023). In crops like mung bean (Kaur et al., 2021), lettuce (Sobucki et al., 2019), tea (Raguraj et al., 2023), maize (Jagadeesan et al., 2023) and wheat (Gezgincioğlu and Atici, 2023), application of PFH has been linked to enhanced growth, yield productivity and crop quality as it significantly improves nutrient uptake, enhances plant resilience to biotic and abiotic stresses and brings notable changes in the quantity and quality of soil microbial communities. In addition, soils amended with PFH show improved soil physicochemical properties and enhanced water retention and nutrient availability, which supports greater plant growth and biomass (Jagadeesan et al., 2023). Its sticky nature may also stabilize soil organic matter (OM) and promote C sequestration by forming aggregates or by binding to mineral particles (Kellerová and Jílková, 2025). Despite these promising outcomes, the majority of studies have primarily focused on the foliar application of PFH, leaving significant gaps in understanding the potential of applying PFH directly on the soil surface.

While the application of PFH generally shows significant results in enhancing plant growth and productivity, its effectiveness can vary depending on the PFH addition rate and state. The addition rate of PFH plays a crucial role in determining its impact on plant and soil responses, with higher doses potentially offering more immediate and sustained effects over time (Bhari et al., 2021; Roy and Jílková, 2025). Supporting this, Kellerová and Jílková (2025) demonstrated that high addition rates of PFH showed stronger effects on soil properties than low addition rates. Additionally, the physical state of PFH may influence its availability and persistence (Roy and Jílková, 2025), and thus its overall impact on plant growth and soil properties. Liquid PFH, the initial form produced, infiltrates the soil rapidly, which enhances nutrient accessibility for microbes (Roy and Jílková, 2025), making it potentially a more effective form of application. Moreover, its dissolved nature enables a gradual and sustained release of N and other essential nutrients, thereby supporting long-term soil nutrient availability and microbial activity (Jagadeesan et al., 2023). In contrast, solid PFH, derived from freeze-drying, while stable under moderate moisture, may release nutrients more abruptly when rehydrated and is therefore more susceptible to leaching under conditions of heavy rainfall (Roy and Jílková, 2025). Understanding these factors is essential in optimizing PFH application that will maximize both agronomic outcomes and environmental sustainability. While previous studies have explained the effects of liquid PFH via foliar application on plant physiology in a greenhouse experiment (Gezgincioğlu and Atici, 2023; Nurdiawati et al., 2019; Rouphael et al., 2017) and both liquid and solid PFH on soil properties under laboratory conditions (Roy and Jílková, 2025), the effect of direct soil application of PFH in different physical states and addition rates on the whole plant–soil system over time remains unknown.

In this study, a 3-month controlled pot experiment was conducted to determine the effects of repeated application of PFH with either no, low (4 t dw ha⁻¹) or high (8 t dw ha⁻¹) addition rates in either liquid or solid states on wheat (Triticum aestivum L.) aboveground and belowground biomass and soil physical, chemical and microbial properties across two harvests (after 1 and 3 months). The present study aimed to test two hypotheses: (1) the effect of the high addition rate will be stronger and will last longer than the effect of the low addition rate and (2) the effect of the liquid state will be stronger and will last longer than the effect of the solid state. By addressing these hypotheses, this study aims to clarify the role of PFH in influencing plant biomass growth and soil health, thereby providing insights essential for optimizing its use as a sustainable organic amendment in crop production systems.

2 Materials and methods

2.1 Collection and preparation of soil and hydrolysate

Soil was collected from a field under conventional farming near Borkovice (Czech Republic; 49°12′76′′N, 14°38′23′′E) in March 2023. Soil (Pseudogleyic Luvisol, WRB) was collected from a 0–20 cm depth at 20 locations in a 0.25-ha area. The collected soil was thoroughly mixed, passed through a 4-mm sieve, and stored at 4°C before being used in the experiment. The hydrolysate was prepared from waste chicken feathers (directly from production without any treatment) with a water content of approximately 35 wt. % (Rabbit Trhový Štěpánov a.s., Czech Republic) in a batch stirred reactor. Exactly 2 kg of feathers was put into a 25-L reactor together with 100 g of malic acid and 15 L of water, and the batch was heated to a temperature of 115–125°C. After five hours, the reactor was cooled down and the reaction product separated by filtration to liquid hydrolysate and solid residue (below 3% wt). Approximately 15–17 L of liquid hydrolysate was prepared from one batch and stored at 4°C before use. A part of the hydrolysate was freeze dried and stored as a solid in a dry and dark location before use. The freeze-dried residue represented 3% of an initial weight.

The chemical properties of the soil and hydrolysate are listed in Table 1. Organic matter (OM) content was determined based on loss on ignition at 450°C for 5 h. To determine the contents of total organic C (TOC), total N (TN) and total P (TP), air-dried samples were ball-milled and analyzed using a Flash Elemental Analyzer (Thermo Scientific) (TOC and TN) or inductively coupled plasma optical emission spectroscopy (ICP-OES) (TP). Dissolved organic C (DOC), dissolved N (DN) and dissolved P (DP) were extracted in deionized water (dH₂O) (1:10 sample:dH₂O ratio) and analyzed in leachates using a TOC-L_CPH/CPN analyzer (Shimadzu) (DOC and DN) and spectrophotometry according to Murphy and Riley (1962) (DP). Soil pH was assessed in a 1:10 sample:dH₂O suspension using a glass electrode. Soil texture was determined based on wet-sieving and sedimentation according to Gee and Bauder (1986). The soil was characterized as silt loam with 19 ± 0.6% sand (2000–63 µm), 55 ± 0.5% silt (63–2 µm), and 21 ± 0.8% clay (< 2 µm) (USDA).

Table 1

Table 1. Content of organic matter (OM), total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), dissolved organic C (DOC), dissolved N (DN), dissolved P (DP) and pH of the soil and hydrolysate.

2.2 Pot experiment

An experiment was conducted in pots (11.5 × 11.5 × 19 cm; surface area = 0.0132 m²) filled with 2.5 L of soil. Ten seeds of spring wheat (Triticum aestivum, variety Alicia, Selgen a.s.) were sown in the soil surface layer and watered with 300 mL of tap water. The next day, pots were treated with 0, 1.2 or 2.4 g dry weight of hydrolysate applied onto the soil surface. These amounts corresponded to 80 mL of dH₂O (0 g; no addition), 40 mL of liquid hydrolysate + 40 mL of dH₂O (1.2 g; low addition rate), 80 mL of liquid hydrolysate (2.4 g; high addition rate), 1.2 g of solid hydrolysate + 80 mL of dH₂O (low addition rate) and 2.4 g of solid hydrolysate + 80 mL of dH₂O (high addition rate). The hydrolysate application was repeated after two months of incubation. The amount of hydrolysate resulted in an addition of 0 t dw ha^–1, 2 t dw ha^–1 (low addition rate), or 4 t dw ha^–1 (high addition rate). Each treatment had eight replicates, giving a total of 40 pots.

Pots were incubated in a growth tent (120 × 120 cm) equipped with growth lights (Mars Hydro 900) set to a 12-h day length at ~20°C for 3 months (March–June 2023). During the incubation, pots were regularly watered with tap water and the order of pots in the tent randomized. After three and five weeks, pots were weeded and wheat seedlings were thinned out to five and three, respectively. After one and three months, four replicates of pots were harvested. Wheat seedlings were carefully separated from the soil and divided into shoots and roots. Roots were washed with tap water and together with shoots dried at 40°C for 48 h to estimate aboveground and belowground biomass. Top 10 cm of soil was collected, homogenized and used for the following physical, chemical and microbial analyses.

2.3 Soil analyses

Content of OM, DOC, DN, DP and pH was analyzed as described earlier. For soil respiration, a 10-g quantity of the fresh soil was placed in 100-mL glass vessels and stored at 20 °C. Three vessels were used as blanks to measure the CO₂ concentration in the air. Each vessel was tightly sealed for 15 hours, after which a 10-mL gas sample was withdrawn using a syringe and stored in a 3-mL evacuated vial (Exetainer®, Labco Ltd., UK). The gas samples were analyzed within 24 h using an HP 5890 gas chromatograph. CO₂ concentrations were determined with a thermal conductivity detector at 100°C, using helium as the carrier gas. Microbial biomass C (C_mic) was extracted using the fumigation-extraction method (Vance et al., 1987) and measured using a TOC analyzer (model TOC-LCPH/CPN, Shimadzu). Water holding capacity (WHC) was calculated as the difference between the weight of a sample saturated with water over 1 h and allowed to drain over 3 h and the weight of an oven-dried sample divided by the weight of the oven-dried sample. In addition, physical fractionation was used to separate the soil samples into three organic and/or mineral fractions as described in Kellerová et al. (2024). In brief, 20 g of an air-dried soil sample was gently submerged in 100 mL of sodium polytungstate (SPT) solution (density = 1.6 g cm^–3) and left overnight to separate the light fraction (< 1.6 g cm^–3; free particulate OM; i.e. the fPOM fraction) and the heavy fraction (> 1.6 g cm^–3). The heavy fraction was subjected to ultrasonication at 440 J mL^–1 in SPT and was then centrifuged at 1370 g for 30 min. The light fraction represented POM occluded in aggregates (the oPOM fraction) and the heavy fraction represented mineral-associated OM (the MAOM fraction). All three fractions were washed thoroughly with dH₂O until the conductivity decreased below 5 µS for the POM fractions and below 50 µS for the MAOM fraction. The fractions were dried at 40 °C to a constant weight, ball milled and analyzed for TOC using a TOC-LCPH/CPN model TOC analyzer coupled with an SSM-5000A solid sample module (Shimadzu).

2.4 Statistical analysis

The effects of the harvest (H1 and H2) and the hydrolysate addition rate (no, low and high) and state (liquid and solid) on soil properties were tested using three-way ANOVAs. A one-way ANOVA was used to test the effect of the addition rate between the two harvests on the soil properties and plant biomass, as well as the TOC content within the fractions. When tests indicated significant differences, Tukey HSD post-hoc tests were used to compare means. Dependent variables were log transformed to satisfy the assumptions of normality and homoscedasticity where needed. Statistica 13 (StatSoft Inc.) was used for statistical analyses.

3 Results

Plant biomass and soil properties were generally affected by the harvest, the addition rate and their interaction, but not by the state (Table 2). The aboveground biomass was on average 696% higher at the second harvest than at the first harvest and was on average 109% higher at the low and high addition rates than at the no addition rate (Figure 1a). The effect of the addition rate was stronger at the second harvest than at the first harvest (F_2,36 = 29.9, p < 0.001), with on average 131% higher biomass at the low and high addition rates than at the no addition rate at the second harvest and no significant differences at the first harvest. A marginally significant effect of the state (p = 0.07) was on average 15% stronger in the liquid state than in the solid state. The belowground biomass was on average 214% higher at the second harvest than at the first harvest (Figure 1b). The effect of the addition rate was marginally significant (p = 0.08) and was on average 74% and 58% stronger at the high and low addition rates, respectively, than at the no addition rate.

Table 2

Table 2. Results of three-way ANOVAs for the effects of the harvest (H), the state (ST), the addition rate (AR), and their interactions on final wheat biomass and soil properties.

Figure 1

Figure 1. Wheat aboveground biomass (a) and belowground biomass (b) at the end of the incubation as affected by the harvest, the addition rate and the state. Values represent mean ± SEM (n = 4). Different uppercase letters indicate significant differences between harvests based on a three-way ANOVA (p < 0.05), while lowercase letters represent significant differences among addition rates within each harvest based on a one-way ANOVA (p < 0.05).

OM content was on average 20% higher at the high addition rate than at the low and no addition rates (Figure 2a). WHC was on average 18% higher at the second harvest than at the first harvest and was on average 9% and 7% higher at the high and low addition rates, respectively, than at the no addition rate (Figure 2b). WHC was also marginally significantly affected by the interaction of the harvest and the state (p = 0.08), with on average 9% stronger effect in the liquid state than in the solid state at the second harvest. Soil pH was on average 5% higher at the second harvest than at the first harvest and was on average 7% and 3% higher at the no and low addition rates, respectively, than at the high addition rate (Figure 2c). The effect of the addition rate was stronger in the second harvest than at the first harvest, with pH at the no and low addition rates 8% and 4% (second harvest) and 5% and 2% (first harvest) higher than at the high addition rate, respectively. DOC content was on average 67% higher at the no addition rate than at the low and high addition rates (Figure 2d), indicating a depletion of soluble C following PFH addition. DN content was on average 30% higher at the first harvest than at the second harvest, was on average 39% higher in the solid state than in the liquid state and was on average 497% and 219% higher at the high and low addition rates, respectively, than at the no addition rate (Figure 2e). The effect of the addition rate was stronger at the first harvest than at the second harvest, with DN content at the high and low addition rates 624% and 436% (first harvest) and 407% and 64% (second harvest) higher than at the no addition rate, respectively. The DN content was on average 7% higher in the liquid state than the solid state at the first harvest, whereas it was on average 142% higher in the solid state than in the liquid state at the second harvest. These results demonstrate that PFH addition stimulated N availability while promoting rapid C and P turnover, pointing to an accelerated microbial activity and potential biostimulant effects in treated soils. DP content was on average 127% higher at the no addition rate than at the low and high addition rates (Figure 2f). This decrease suggest rapid microbial utilization or plant uptake of available C and P, consistent with an enhanced nutrient cycling response to PFH addition.

Figure 2

Figure 2. Organic matter (OM) content (a), water holding capacity (WHC) (b), pH (c), content of dissolved organic C (DOC) (d), dissolved N (DN) (e), dissolved P (DP) (f), soil respiration (g) and microbial biomass C (C_mic) (h) at the end of incubation as affected by the harvest, the addition rate and the state. Values represent mean ± SEM (n = 4). Different uppercase letters indicate significant differences between harvests based on a three-way ANOVA (p < 0.05), while lowercase letters represent significant differences among addition rates within each harvest based on a one-way ANOVA (p < 0.05).

Soil respiration was on average 27% higher at the first harvest than at the second harvest, was on average 9% higher in the solid state than in the liquid state, and was on average 13% and 6% higher at the low and high addition rates, respectively, than at the no addition rate (Figure 2g). Soil respiration was also affected by the interaction of harvest and PFH state (F_1,36 = 19.3, p < 0.001; Table 2), indicating on average 36% higher respiration in the solid state than in the liquid state at the second harvest, whereas on average 8% higher respiration in the liquid state than in the solid state at the first harvest. The effect of the addition rate was stronger at the first harvest than at the second harvest, with respiration at the low and high addition rates 29% and 18% higher, respectively, than at the no addition rate at the first harvest, with no significant differences observed at the second harvest. C_mic content was on average 22% higher at the second harvest than at the first harvest (Figure 2h).

TOC content was generally highest in the MAOM fraction (82%), intermediate in the oPOM fraction (13%) and lowest in the fPOM fraction (5%) (F_2,87 = 340.2, p < 0.001) (Figures 3a–c). TOC content in both the fPOM and oPOM fractions was affected by the harvest or the addition rate (Table 3). TOC content in fPOM was on average 39% higher at the first harvest than at the second harvest and was on average 31% higher at the high and low addition rates than at the no addition rate (Figure 3a). TOC content in oPOM was on average 61% higher at the first harvest than at the second harvest (Figure 3b).

Figure 3

Figure 3. Total organic carbon (C) content in fPOM (a), oPOM (b) and MAOM (c) fraction at the end of incubation as affected by the harvest, the addition rate and the state. Values represent mean ± SEM (n = 3). Different uppercase letters indicate significant differences between harvests based on a three-way ANOVA (p < 0.05), while lowercase letters represent significant differences among addition rates within each harvest based on a one-way ANOVA (p < 0.05).

Table 3

Table 3. Results of three-way ANOVAs for the effects of the harvest (H), the state (ST), the addition rate (AR) and their interactions on soil organic carbon fractions.

4 Discussion

PFH derived from waste poultry feathers holds potential benefits for plant growth and soil health (Bhari et al., 2021; Raguraj et al., 2023). However, previous research has been limited to the effects of foliar PFH application or laboratory-scale assessments of its impact on plant growth or soil properties (Gezgincioğlu and Atici, 2023; Sobucki et al., 2019; Kellerová and Jílková, 2025; Roy and Jílková, 2025). To address this gap, the present study investigates the impact of PFH on wheat biomass and the soil physical, chemical and microbial properties in a controlled pot experiment. Uniquely, it is the first study to determine the effects of repeated application of PFH at different addition rates in liquid and solid states, offering new insights into its potential for sustainable crop production.

The addition of PFH enhanced wheat biomass and improved soil properties. However, the effect of the addition rate was not significant, which disproves the first hypothesis. While both the low and high PFH addition rates similarly enhanced aboveground and belowground biomass (Figure 1), this positive effect became more pronounced at the second harvest, indicating a cumulative benefit of PFH presence on plant biomass growth over time, irrespective of the quantity applied. This comparable response at low and high addition rates may reflect a saturation effect, where even the lower addition rate provides sufficient nutrients and bioactive compounds to stimulate microbial activity and plant growth. At higher PFH concentrations, additional biomass gains may be limited, potentially due to the higher content of salts or intermediate compounds, as observed by Nurdiawati et al. (2019). Similar effects have been reported by Raguraj et al. (2023) who showed that regardless of the addition rate, PFH treatment consistently led to significant improvements in plant biomass, morphological characteristics and nutrient levels in leaves and roots compared to the untreated control. The high addition rate, however, had a stronger effect on the OM content (Figure 2a) via the fPOM content (Figure 3a), contributing to improved WHC (Figure 2b), likely due to the cumulative input of OM from the PFH over time (Nurdiawati et al., 2019) or decreased decomposition of recalcitrant soil OM at the expense of the PFH as the available substrate (Cheng and Kuzyakov, 2005). On the other hand, a decreasing trend in soil pH was observed with the addition of PFH (Figure 2c), most likely due to the acidic nature of the PFH itself (Table 1). This pH reduction may have enhanced nutrient availability and mobility, thereby accelerating the depletion of available DOC (Figure 2d) and DP (Figure 2f), which were higher at the no addition rate. This is supported by a previous study showing that acidic conditions increase the solubility and mobility of soil nutrients, potentially enhancing their uptake or leaching, leading to a depletion (Neina, 2019). On the contrary, increased DN content (Figure 2e) with PFH addition, particularly at the high addition rate, can be attributed to the high abundance of N in the PFH (Table 1) which may have stimulated microbial decomposition of native soil C. Such a mechanism could explain the observed increase in soil respiration with the addition of PFH (Figure 2g), reflecting higher microbial activity through the provision of available nutrients, C_mic remained unaffected by PFH addition (Figure 2h). The similar effect has been observed by Babur et al. (2021), where N-based fertilizers positively enhanced microbial respiration in grasslands, supporting the plausibility of this explanation. Similarly, PFH addition had no significant effect on TOC content in the oPOM (Figure 3b) or MAOM (Figure 3c) fractions. This implies that PFH acts more as a source of readily available nutrients that enhance microbial functioning rather than promoting microbial growth (Możejko and Bohacz, 2023) or C stabilization (Kellerová and Jílková, 2025).

The effect of PFH was generally stronger in the liquid state than in the solid state, corroborating the second hypothesis. Liquid PFH enhanced aboveground biomass across harvests (Figure 1a), suggesting generally enhanced and long-term nutrient availability for plant growth. Moreover, WHC was enhanced by the liquid PFH at the second harvest (Figure 2b), i.e. after a 3-month incubation, suggesting that PFH apparently has a long-term and cumulative effect on water retention due to its sticky nature. In contrast, the liquid PFH increased DN content by 7% (Figure 2e) and microbial activity by 8% (Figure 2e) at the first harvest than at the second. This indicates that the liquid PFH was relatively quickly depleted from the soil due to its liquid form availability, but most importantly because the application of PFH led to a decrease in pH to more acidic values (6.7) (Figure 2c), which are more favorable to nutrient availability (Neina, 2019) and were more evident at the second harvest than at the first. On the other hand, the solid PFH led to higher DN content and microbial activity at the second harvest, regardless of the decrease in pH, indicating that solid PFH is more persistent and less sensitive to environmental changes. These results, however, contradict our previous laboratory incubation study showing stronger and longer-term effects of liquid rather than solid PFH (Roy and Jílková, 2025). In the previous study, larger volumes of water were used to flush the laboratory microcosms to simulate regular rainfall and collect soil leachates from under the microcosms, whereas in the current study, only small volumes of water were used just to water the pots, keeping them moistened. The solid PFH might thus be sensitive to leaching when heavy rainfall occurs. In summary, liquid PFH offers a rapid, fast-release nutrient pulse that supports immediate plant growth and microbial activity but is susceptible to a decrease in the pH, increasing nutrient availability and depletion. The solid PFH, on the other hand, provides a slower, more sustained nutrient release and is less sensitive to pH changes, providing a longer-term support.

5 Conclusion

The present study showcased the effect of PFH on wheat biomass growth and soil properties at different addition rates in liquid and solid states for the first time. The pot experiment revealed that, regardless of the addition rate, PFH consistently enhanced wheat biomass growth and improved soil properties over two harvests. While the addition rate did not consistently dictate the magnitude of these effects, the cumulative benefit of PFH on plant biomass became pronounced over time. The liquid PFH, in particular, consistently supported plant biomass growth and water retention and provided short-term effects on soil microbial activity and N availability compared to the solid PFH, rather supporting soil microbial activity and N availability in the longer term. These findings thus highlight the potential of both liquid and solid PFH as valuable soil amendments for sustainable crop production, with their respective benefits and considerations for nutrient management.

Data availability statement

The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found below: The measured data on soil analyses are deposited online on Zenodo, via 10.5281/zenodo.15863176.

Author contributions

AR: Data curation, Formal Analysis, Software, Visualization, Writing – original draft, Writing – review & editing. VJ: Conceptualization, Funding acquisition, Investigation, Methodology, Project administration, Supervision, Validation, Writing – review & editing.

Funding

The author(s) declare financial support was received for the research and/or publication of this article. This study is a result of the project “SS06020267 Innovative utilization of hydrolysate from animal waste for improvement of agricultural soil quality”, co-financed from the state budget by the Technology Agency of the Czech Republic and the Ministry of the Environment of the Czech Republic under the Environment for Life Programme. This project is funded under the National Recovery Plan from the European Recovery and Resilience Instrument. This study is also financed from the Czech Academy of Sciences [Strategy AV21, programs Foods for the Future and Sustainable Food Production and Consumption].

Acknowledgments

The authors would like to thank Farma JECH s.r.o. for providing the soil, Olga Šolcová and Stanislav Šabata for preparation of the hydrolysate, Gabriela Mühlbachová for providing wheat seeds, and Monika Soudková, Jiří Petrásek and Eva Špotová for help with laboratory analyses.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declare that no Generative AI was used in the creation of this manuscript.

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