Application of Lignin for Slope Bioengineering: Effect on Soil Improvement and Plant Growth
Abstract
:1. Introduction
2. Literature Review
3. Materials and Methods
3.1. Materials Used
3.2. Experimental Program
3.2.1. Soil Specimen Preparations
3.2.2. Soil Testing
4. Results and Discussion
4.1. Compressive and Shear Strength Characteristics
- -
- For each measurement, at least five pocket penetrometer tests were conducted, and the average value was used to estimate the soil surface strength. The PP measurements were performed in different parts of the soil samples. As the soil mass was not homogenous (due to the soil nature and experimental preparations), different values were sometimes obtained, depending on the point selected for the measurement.
- -
- For each experiment, the soil surface was sprayed with 100 mL of water twice per week to stimulate seed germination and growth, and changes in moisture on the soil surface contributed to the soil inhomogeneity.
- -
- Over time, the soil samples had a natural tendency to dry on the surface, initiating surface cracks. This process contributed to the soil inhomogeneity as well, and impacted the measured soil strength.
4.2. Visual Observations and Water Content
4.3. Seed Germination and Growth
5. Conclusions
- -
- The application of lignin biopolymer increased the strength of all three tested soil types. Both pocket penetrometer and vane shear test results indicated that the soil treated with lignin produced greater strength, especially when a 3% lignin solution was used. For high-plasticity Soil 1, the maximum increase in the strength, compared to the untreated control soil sample, occurred after the first 10 days, while for low-plasticity Soil 2, the maximum increase in the strength occurred later, within 20–30 days.
- -
- The increase in soil strength was greater when lignin solutions were mixed with soil (Method 1) compared to the other method (Method 2) when lignin solutions were sprayed on the surface of the soil mass.
- -
- The lignin-treated soil could retain more water over the long term compared to the untreated soil. This was more pronounced for very plastic soil (Soil 1) and non-plastic sand (Soil 3) than for Soil 2. This extra moisture could contribute to better vegetation growth, leading to greater resistance to soil erosion.
- -
- Both lignin-treated and untreated soils produced similar results on seed germination and growth, suggesting that lignin does not have a negative effect on vegetation. The outcomes of this study indicate that the addition of lignin to soil can improve soil strength without negative effects on the environment and vegetation growth, which is important for alternative slope bioengineering methods.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Soil Type | Lignin Type | Additive Dosage (%) | Curing Period | Test Method | Key Findings | Reference |
---|---|---|---|---|---|---|
Aggregate mixed | Lignosulfonate | - | 7–28 days | UCS, durability |
| Bolander [14] |
Clays | Lignosulfonate | 0.5, 0.6, 1, 1.5 | 0–28 days | UCT, EC |
| Indraratna et al. [15] |
Sandy silt | Lignosulfonate | 0.5, 1, 2, 3, 4 | 7–28 days | TT |
| Chen et al. [16] |
Silty soil | Lignin, quick lime | 2, 5, 8, 12, 15 | 0–60 days | UCT, CBR, Vs |
| Zhang et al. [17,18,19] |
Silt soil | Lignin, lime, cement, fly ash | 7, 10, 12, 14, 16 | 1–28 days | UCT |
| Kong et al. [20] |
Silty soil | Sulfur-free lignin | 3, 7, 10, 12, 15 | 1–60 days | UCT |
| Liu et al. [21,22] |
Black cotton soil | Sodium lignosulfonate | 1, 3, 6, 9, 12 | 3, 7, 28 days | UCT, DST |
| Singh et al. [23] |
Dispersive soil | Calcium-lignosulfonate | 0.5, 1, 2, 3, 4 | 28 days | UCT |
| Ji et al. [24] |
Clay mixed granite sand | Calcium-lignosulfonate | 0.5, 1, 1.5, 2 | 0, 7, 14, 28, 90 days | UCT, HT |
| Amulya et al. [25] |
Clay | Lignin-coir fibers, lime | 0.5, 1, 1.5 | – | UCT, CBR, VST |
| Boobalan and Sivakami, [26] |
Silty soil | Calcium lignosulfonate | 0.5, 1.0, 1.5 | 28 days | UCT, DST |
| Du et al. [27] |
Clay soil | Calcium lignosulfonate, granite sand | 0.25, 0.5, 1, 1.5; 30, 40, 50 | 7, 14 days | DST |
| Varsha et al. [28] |
Silty soil | Lignosulfonate | 1, 3 | 1–35 days | TT, UCT |
| Bagheri et al. [8] |
Clay soil | Sodium lignosulfonate | 0.5, 1.0, 1.5 | 7, 28, 90 | UCT |
| Vakili et al. [29] |
Soil Type | Biopolymers | Content (%) | Method | Vegetation Type | Curing Days | Outcomes | Reference |
---|---|---|---|---|---|---|---|
Sand | Lignin-(guaiac, syringyl, p-hydroxyl phenyl) | 2 | Mixing—spraying | Agriophyllum squarrosum, Artemisia desertorum Spreng, etc. | 120–150 | The lignin biopolymer and the species used could form a community within 2 to 3 years and stabilize the desert dune significantly. | Hanjie et al. [34] |
Red–yellow sand | Xanthan gum, β-glucan | 0.5 | Mixing | Oats (600 seeds) | 7–21 | Xanthan gum and β-glucan biopolymers stimulated seed germination and growth in natural and cultured soil. | Chang et al. [39] |
Granular soil | IPCs, HPAN, PDADMAC, KNO3 | 1–2 wt.% | Mixing | Sudan grass | 1095–1460 | IPCs offer a considerable soil binder and enhance grass growth compared to the other polymers. | Zezin et al. [35] |
Clayey soil | Xanthan gum, guar gum, agar gum, beta-glucan | 0.25, 0.5, 0.75, 1 | Mixing | Oats (160 seeds) | 2–14 | Xanthan gum efficiently promotes vegetation growth and increases the seed germination ratio by about 300% at 0.5% compared to other biopolymers. | Ni et al. [40] |
Silt | Xanthan gum, guar gum, agar gum | 0.5 | Mixing | Ryegrass | 7, 14, 21, 28 | Xanthan gum-treated silt has the highest growth and germination rate compared to guar- and agar-treated silt. | Wang et al. [44] |
Sand | Xanthan gum-starch | 0.5 | Spraying | Turfgrasses | 16 | Xanthan gum enhanced water retention, soil cohesion, and vegetation growth to improve erosion resistance. | Tran et al. [33] |
Sand | Polyurethane | 0–20 | Mixing | Ryegrasses (60 g of seeds) | 10–60 | Polyurethane polymer did not show effective promotion of vegetation growth compared to untreated sand, especially at concentrations above 10%. | Liu et al. [46] |
Sand | Xanthan gum, cationamyl, potassium nitrate, carboxy methyl cellulose | 0.5–1 | Mixing | Festuca, Poa pratensis, Lolium perenne and Trifolium repens seeds | 1–27 | Biopolymers are capable of improving the overall vegetation growth. | Nikolovska et al. [37] |
Weathered granite soil | Xanthan gum, starch, β-glucan | 0.45–0.5 | Mixing—spray | Seeds | 30 | Xanthan gum, starch, and β-glucan compounds were implemented using the wet-spraying method to strengthen the structure and promote vegetation growth on levee slopes. | Seo et al. [47] |
Sand | Hydrophilic polysaccharide biopolymer (HPB) | 0.05–1 | Spraying | Ryegrass and Bermuda grass | 12 | HPB concentration of less than 5% promotes vegetation growth. | Che et al. [48] |
Clay soil | Xanthan gum | 0.25–1 | Mixing | Oats (160 seeds) | 1–14 | Xanthan gum promotes vegetation growth at 0.25% to 0.5% dosage; above 0.5% may impede vegetation growth. | Ni et al. [49] |
Desert sand | MICP | 0.1–0.5 M | Spraying | Heracleum persicum | 7–30 | MICP biopolymer promotes the germination of Heracleum persicum. | Naeimi et al. [36] |
Loess | Xanthan gum | 0–1 | Mixing | Oats (160 seeds) | 14 | Xanthan gum yields higher germination from 0.25% to 1% dosage and high root content at 0.25% to 0.75%. | Ni et al. [50] |
Clay | Xanthan gum | 0–4 | Mixing | LP seeds | 60 | Xanthan gum promotes LP growth, and increasing Xanthan dosage increases the growth rate. | Wan et al. [51] |
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Gratchev, I.; Tang, Q.; Akosah, S.; Sugawara, J. Application of Lignin for Slope Bioengineering: Effect on Soil Improvement and Plant Growth. Appl. Sci. 2025, 15, 4173. https://doi.org/10.3390/app15084173
Gratchev I, Tang Q, Akosah S, Sugawara J. Application of Lignin for Slope Bioengineering: Effect on Soil Improvement and Plant Growth. Applied Sciences. 2025; 15(8):4173. https://doi.org/10.3390/app15084173
Chicago/Turabian StyleGratchev, Ivan, Qianhao Tang, Stephen Akosah, and Jun Sugawara. 2025. "Application of Lignin for Slope Bioengineering: Effect on Soil Improvement and Plant Growth" Applied Sciences 15, no. 8: 4173. https://doi.org/10.3390/app15084173
APA StyleGratchev, I., Tang, Q., Akosah, S., & Sugawara, J. (2025). Application of Lignin for Slope Bioengineering: Effect on Soil Improvement and Plant Growth. Applied Sciences, 15(8), 4173. https://doi.org/10.3390/app15084173