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Miscanthus x giganteus phytoremediation of soil contaminated with petroleum was assessed in this study. A method of soil sample preparation for determining the total content of petroleum products by infrared spectrophotometry has been developed. It is a one-stage extraction method with minimal use of carbon tetrachloride as an extractant. This soil sample preparation method was environmentally friendly and cost-effective, as it required a significantly lower amount of extractant (15–30 ml of tetrachloromethane) compared to the commonly used threefold extraction method, which uses up to 150 ml of extractant. The extraction degree of petroleum products (PP) was determined to be from 81.78 % to 94.22 % after two days of extraction using the additive method of determining PP. It was observed that the presence of different fertilizer additives in the soil samples led to a reduction in the determined PP content in the following series: “without fertilizer” – “Biochar” additive – “Biohumus” additive. These results were compared with reference samples that did not involve the use of Miscanthus x giganteus. Furthermore, the main thermolysis stages of petroleum products sorbed by the soil matrix and the thermal behavior of an artificial soil sample spiked with PP were examined. Detailed interpretation of thermograms of laboratory soil samples was conducted at various phytoremediation stages.

Miscanthus × giganteus (M × g) is a promising energy crop in phytotechnology with biomass production. Despite considerable vegetation and harvest under varying climate conditions and across different soils, field-scale studies on utilising M × g remain scarce. Analysing the literature and our own findings, this study intends to highlight the potential of M × g phytotechnology for revitalising non-agricultural lands (NAL), including brownfields, and illustrate the expediency of applying biochar to enhance biomass yield, energy efficiency, and economic feasibility. To validate the feasibility of M × g production on brownfields, two scenarios within the value chain “biomass–biogas–electricity” for green harvest were examined. The assumptions were as follows: (1) a methane yield of 5134 m3 ha−1 y−1, and (2) substrate-specific methane yields of 247 and 283 mL (g oDM)−1 for the first and subsequent years, respectively. The findings suggest that Scenario 2 is better suited for cultivating M × g on brownfields/NAL, being more sensitive and eliminating inaccuracies and the generalisations of results. From the third year onward, the revenue of M × g production on biochar-amended brownfields showed greater potential for future profitability. Future research should confirm the positive trend in the energy efficiency ratio of M × g phytotechnology on a larger scale, particularly in real brownfield applications.

During a survey of plant parasitic nematodes associated with Miscanthus × giganteus which was carried out in Ukraine in 2016–2017, an occurrence of Rotylenchus agnetis Szczygieł, 1968, Rotylenchus pumilus Perry, 1959 and Paratylenchus nanus Cobb, 1923 was found. To the best of our knowledge this is the first record of a parasite species which can damage M. × giganteus. The species were described morphologically and using molecular tools. Further profound study on pathogenicity of those species is needed.

Analysis of the nematode community has been considered a key indicator of soil health. In this study, the assessment of nematodes was performed two times during the third growing season in soil contaminated by chemical elements where Miscanthus × giganteus was cultivated in the years 2019–2022. A morphological approach was used to identify the nematode communities that showed sensitivity to the level of soil contamination. In contrast, the value of M × g dry biomass was a more conservative indicator and displayed only a small yield, which decreased (3.6%) at the highest level of soil contamination by lead to 290.5 ± 75.4 µg/g. Principal component analysis revealed four trends associated with the coherent variability of contamination in soil and various organs of M × g. The variability of elements was reflected by the first three principal components and did not affect the nematode community. The variability of lead concentration was associated with principal component 4, which was the largest driver of changes in the nematode community. The trophic structure of the nematode communities was the most sensitive to soil contamination by lead. A decrease in the Structural Index was the general indicator in the transformation of the nematode community structure due to increasing levels of soil contamination.

The second generation energy crop Miscanthus x giganteus (Mxg) was cultivated in pots with mixtures of clean and petroleum industry contaminated soil affected by petroleum, Pb, Zn contamination and high salinity. The survival rate reached 100%, nevertheless the biomass parameters were negatively affected even in the lowest proportion of contaminated soil. In the lowest contamination, where the plant grew still quite successfully, C10-C40 degradation was significantly enhanced compared to the unplanted control with degradation of 58 ± 14%. The plant contribution to aliphatics degradation was significantly correlated with biomass, thus it was negligible in higher contamination. A similar pattern was documented in development of the soil bacterial community. The shift in community structure after Mxg cultivation was observed mainly in the soil with the lowest contaminant proportion, though an increase of bacterial diversity in the miscanthus rhizosphere was observed in all cases. Relative abundance of Actinobacteria was reduced on behalf of several less abundant phyla (Verrucomicrobia, Bacterioides, Acidobacteria). The majority of genera identified as potential petroleum degraders (Pseudomonas, Shinella, Altererythrobacter, Azospirillum, Mesorhizobium, Dyella) were more abundant in contaminated soil with miscanthus, suggesting that Mxg could be a promising crop for phytomanagement of petroleum contaminated soils but salt phytotoxicity needs to be mitigated first.

The need to achieve the sustainability goals and to reduce the continuous exploitation of the limited urban areas increases requests for the regeneration of brownfields. The current study aims to review the state of brownfields in the Northern Czech Region and neighboring German (Saxony) and Polish (Silesian) Regions which share a common geological background and environmental problems. The peculiarities of the brownfield’s properties related to the term, classification, legislative framework, access to available data, degree of contamination, and remediation methods were the focus of this review. It was established that the state with brownfield identification and transformation is better in the Czech Republic, followed by Germany, with lower awareness in Poland. The relevant examples of successful brownfield revitalization and the importance of educational components were introduced. A prospective application of the phytotechnology with the second-generation crops for the remediation of brownfields was discussed. The utilization of Miscanthus spp. for marginal lands with low contamination can provide an economic return by having biomass converted into energy or bioproducts and the utilization of the accompanied waste as carbon-rich biochar which can indeed support phytoremediation, enhance plants’ growth and serve as a medium for carbon sequestration. The next steps in the research have to concentrate on comparison of the rehabilitation methods introduced for the targeted regions with the global approach in brownfield redevelopment along with the practical ensuring the phytotechnology potential at the selected brownfields.

This editorial belongs to the Special Issue “Impact of Nutrients and Trace Elements in Soil on Plant Growth: Case of the Second-Generation Energy Crops” [...]

Soil contamination with trace elements (TEs) is a pressing problem limiting the cultivation of agricultural crops; however, the non-food energy crop Miscanthus × giganteus (M×g) can be grown on such soil. The effect of a new plant growth regulator (PGR), Kamethur, and conventional Charkor was studied when M×g was cultivated in TE-contaminated soils from Všebořice and Chomutov, in the Northern Czech Republic. Kamethur was beneficial for achieving a higher leaves and stem biomass (by 57.1 and 126%, respectively) in the more contaminated Všebořice soil, while Charkor increased only the leaves biomass (49.5%). Analysis of the comprehensive bio-concentration index showed that Charkor decreased stem accumulation of elements essential for plant development (EEs), as well as the potentially toxic (PTEs) elements, by 33.3 and 11.4%, respectively. Kamethur decreased stem accumulation of EEs by 11.4% and increased the accumulation of PTEs by 23.3%. Statistical evaluation of the current results and literature data illustrated the ability of Charkor to reduce the uptake of PTEs, which is critical for converting clean biomass to bioproducts. Further research should confirm the influence of PGRs on the bioparameters and phytoremediation processes of M×g at the field plantation level.

The short-term effects of soil amendments on the structure, diversity and function of a nematode community of Miscanthus × giganteus was investigated. Crop was cultivated on marginal, nutrient-poor land amended with biochar in single and double doses (BD1 and BD2), biogas digestate (D), sewage sludge (SS), and hemicellulose waste (HW). Sampling was done after planting, in the middle and end of vegetation; morphology-based approach was used. 28 nematode taxa were identified, including 5 bacterivores genera, 4 fungivores genera, 5 herbivores genera (11 species), 2 omnivores genera, 5 predators genera. The general linear models, correspondence analysis and clustering were applied for evaluation. The total abundance of nematode taxa Filenchus, Dorylaimus, Cephalobus, Panagrolaimus, Aphelenchus, and Ditylenchus was depended on the sampling time and amendments. The incorporation of amendments affected nematode food web and resulted in suppression of plant-parasitic nematodes (PPNs). It was revealed that community structure was more mature for SS, less stable for D and had inconclusive effects for BD1, BD2, and HW. Using amendments ensured pest control benefits which is important given concern that PPNs can inflict crop damage during increased cultivation of M × g. Further research is needed to examine amendments which can minimise PPNs without reducing populations of nitrogen-fixing bacterivores and fungivores.

Paulownia tomentosa (Thunb.) Steud is a drought-resistant, low-maintenance and fast-growing energy crop that can withstand a wide range of climatic conditions, provides a high biomass yield (approximately 50 t DM ha−1 yr−1), and develops successfully in contaminated sites. In Kazakhstan, there are many historically contaminated sites polluted by a mixture of xenobiotics of organic and inorganic origin that need to be revitalised. Pilot-scale research evaluated the potential of P. tomentosa for the phytoremediation of soils historically contaminated with organochlorine pesticides (OCPs) and toxic trace elements (TTEs) to minimise their impact on the environment. Targeted soils from the obsolete pesticide stockpiles located in three villages of Talgar district, Almaty region, Kazakhstan, i.e., Amangeldy (soil A), Beskainar (soil B), and Kyzylkairat (soil K), were subjected to research. Twenty OCPs and eight TTEs (As, Cr, Co, Ni, Cu, Zn, Cd, and Pb) were detected in the soils. The phytoremediation potential of P. tomentosa was investigated for OCPs whose concentrations in the soils were significantly different (aldrin, endosulfans, endrin aldehyde, HCB, heptachlor, hexabromobenzene, keltan, methoxychlor, and γ-HCH) and for TTEs (Cu, Zn, and Cd) whose concentrations exceeded maximum permissible concentrations. Bioconcentration (BCF) and translocation (TLF) factors were used as indicators of the phytoremediation process. It was ensured that the uptake and translocation of contaminants by P. tomentosa was highly variable and depended on their properties and concentrations in soil. Besides the ability to bioconcentrate Cr, Ni, and Cu, P. tomentosa demonstrated very encouraging results in the accumulation of endosulfans, keltan, and methoxychlor and the phytoextraction of γ-HCH (TLFs of 1.9–9.9) and HCB (BCFs of 197–571). The results of the pilot trials support the need to further investigate the potential of P. tomentosa for phytoremediation on a field scale.

The phytoremediation of industrial crops is becoming popular for the revitalization of land contaminated by trace elements (TEs). This approach combines biomass production with the improvement of soil health. To implement phytoremediation and derive sufficient dry biomass, crop production must be adequately supported by agricultural practices, including the application of bioinoculants. The current study aims to test the influence of several plant growth-promoting bacteria (PGPB), isolated from TEs-contaminated soil—i.e., Stenotrophomonas maltophilia KP-13, Bacillus altitudinis KP-14, and Pseudomonas fluorescens KP-16 and their consortia on the phytoremediation of the industrial crop M. × giganteus cultivated in the same TEs-contaminated soil. Contrary to expectations, the effects of PGPB on the biomass harvest were low. The most significant increase was detected in leaf biomass treated with a consortium of tested PGPBs. More significant effects were detected in the uptake of individual TEs. The phytoparameters of translocation factor, comprehensive bioconcentration index and uptake index were used to characterize the behavior of the TEs; Cr; Mn; Ni; Cu; Zn; Sr; V; and Pb in the presence of isolates. Plants treated with PGPB strains accumulated minimal concentrations of Cu and Pb in their aboveground biomass, while a tendency for Zn accumulation in the leaves and stems, and Sr accumulation in the leaves was observed. The obtained results reveal the combinations of isolates that lead to the minimal uptake of TEs into the stems and the simultaneous increase in DW. This study provides more insight into the leading factors of phytoremediation supported by PGPB and can be helpful when M. × giganteus is grown on TEs-contaminated soils of different origins.

The impact of the plant growth regulators (PGRs) Stimpo, Regoplant, and Charkor on the production of the second-generation energy crop Miscanthus × giganteus on marginal post-military soil was investigated during two vegetation seasons. The land, previously a tank training polygon, has not been in use since 1990 and has become marginal. Biological parameters (stem, shoot, and root lengths) and dry biomass values were evaluated in relation to the applied treatments. The multivariate general linear model (M-GLM) results showed a positive influence of Charkor on M. × giganteus development; the effect was markedly higher in the second year of vegetation. The impact of Stimpo and Regoplant was less noticeable; nevertheless, certain combinations of treatments showed satisfactory results. The M-GLM approach detected the inter-influence of the main factors of the production process, i.e., PGRs, soil, and year of growing. The results showed the predominant influence of year, PGRs and combined factor PGRs × year on the biological parameters; the other studied factors and their combinations were not as effective. Further research should focus on verifying the field-scale results for the M. × giganteus plantation established in a post-military area and compare the lab and field studies.

Miscanthus × giganteus (M. × giganteus) is a perspective plant produced on marginal and contaminated lands with biomass used for energy or bioproducts. In the current study, M. × giganteus development was tested in the diesel-contaminated soils (ranged from 250 mg kg−1 to 5000 mg kg−1) and the growth dynamic, leaves quantity, plants total area, number of harvested stems and leaves, SPAD and NPQt parameters were evaluated. Results showed a remarkable M. × giganteus growth in a selected interval of diesel-contaminated soil with sufficient harvested biomass. The amendment of soil by biochar 1 (produced from wastewater sludge) and biochar 2 (produced from a mixture of wood waste and biohumus) improved the crop’s morphological and physiological parameters. Biochar 1 stimulated the increase of the stems’ biomass, while biochar 2 increased the leaves biomass. The plants growing in the uncontaminated soil decreased the content of NO3, pH (KCl), P2O5 and increased the content of NH4. Photosynthesis parameters showed that incorporating biochar 1 and biochar 2 to the diesel-contaminated soil prolonged the plants’ vegetation, which was more potent for biochar 1. M. × giganteus utilization united with biochar amendment can be recommended to remediate diesel-contaminated land in concentration range 250–5000 mg kg−1.

Second-generation biofuel crop miscanthus is one of the most promising plants tested for phytomanagement of contaminated sites. In this preliminary pot case study, the most used hybrid Miscanthus x giganteus was cultivated in three different real contaminated soils: agricultural soil contaminated with Cd; post-military soil slightly contaminated with Zn, Pb and Cd; and soil contaminated by petroleum industry with metals and hydrocarbons. The stress response of plants and soil microbial communities was monitored to receive data that are important for successful phytomanagement application. With metals only, the plant grew well, and chlorophyll fluorescence measurement proved their good vitality. Changes in leaf anatomy (leaf thickness and sclerenchyma cells area) were additionally determined in post-military soil compared to agricultural. On the contrary, in petroleum-contaminated soil, the biomass yield was too reduced and also physiological parameters were significantly decreased. The response of microbial communities also differed. In agricultural soil, no microbial stress was determined. In post-military soil, it became reduced during the experiment, and in petroleum contamination, it increased year-on-year. It could be concluded that miscanthus is suitable for cultivation in metals contaminated soils with potential for microbial communities support, but in soil contaminated by the petroleum industry, its application did not seem meaningful.

Applying phytotechnologies with energy crops on lands contaminated with trace elements provides cellulosic biomass and improves soil health. The process can be reflected in changes in the soil nematode community structure. This study assessed the nematode community composition of soil with Miscanthus grown with different agronomic practices. The research was conducted at Fort Riley, Kansas, USA, in soil with aged contamination by Pb at 1000 to 1500 mg/kg. The experimental design was a randomized complete block composed of four replications of five treatments: Control-undisturbed mixed plant cover and four conditions of Miscanthus growth, which consisted of No-till, Till (immediately before planting), Till + P, and Till + biosolids. Analysis of abundance, diversity, and community functional status indicators showed differential sensitivity of nematode taxa to agronomic treatments. Significant transformations in the nematode trophic group structure occurred under Miscanthus cultivation compared with the undisturbed mixed plant cover. Shannon and Pielou index response to agronomic treatments illustrated decreasing nematode community diversity with all Miscanthus agronomic conditions. However, agronomic practices led to increasing nematode community maturity, but those effects varied between spring and fall seasons. Increasing herbivores and omnivore-predators were the primary drivers of the observed changes in the nematode community due to planting Miscanthus. The nematode ecological structure indicators suggested that growth in Pb-contaminated land using different agronomical practices likely affects essential soil processes. More study is needed to define the effects of pre-plant tillage and amendments to soil nematode communities and Miscanthus yield over multiple growing seasons of this perennial crop.

Use of plant growth-promoting bacteria (PGPB) for cultivation of the biofuel crop Miscanthus × giganteus (Mxg) in post-military and post-mining sites is a promising approach for the bioremediation of soils contaminated by metals. In the present study, PGPB were isolated from contaminated soil and screened for tolerance against abiotic stresses caused by salinity, pH, temperature, and lead (Pb). Selected strains were further assessed and screened for plant growth-promoting attributes. The isolate showing the most potential, Bacillus altitudinis KP-14, was tested for enhancement of Mxg growth in contaminated soil under greenhouse conditions. It was found to be highly tolerant to diverse abiotic stresses, exhibiting tolerance to salinity (0–15%), pH (4–8), temperature (4–50 °C), and Pb (up to 1200 ppm). The association of B. altitudinis KP-14 with Mxg resulted in a significant (p ≤ 0.001) impact on biomass enhancement: the total shoot and dry root weights were significantly enhanced by 77.7% and 55.5%, respectively. The significant enhancement of Mxg biomass parameters by application of B. altitudinis KP-14 strongly supports the use of this strain as a biofertilizer for the improvement of plant growth in metal-contaminated soils.

Miscanthus x giganteus (Mxg) is a promising second-generation biofuel crop with high production of energetic biomass. Our aim was to determine the level of plant stress of Mxg grown in poor quality soils using non-invasive physiological parameters and to test whether the stress could be reduced by application of plant growth regulators (PGRs). Plant fitness was quantified by measuring of leaf fluorescence using 24 indexes to select the most suitable fluorescence indicators for quantification of this type of abiotic stress. Simultaneously, visible stress signs were observed on stems and leaves and differences in variants were revealed also by microscopy of leaf sections. Leaf fluorescence analysis, visual observation and changes of leaf anatomy revealed significant stress in all studied subjects compared to those cultivated in good quality soil. Besides commonly used Fv/Fm (potential photosynthetic efficiency) and P.I. (performance index), which showed very low sensitivity, we suggest other fluorescence parameters (like dissipation, DIo/RC) for revealing finer differences. We can conclude that measurement of leaf fluorescence is a suitable method for revealing stress affecting Mxg in poor soils. However, none of investigated parameters proved significant positive effect of PGRs on stress reduction. Therefore, direct improvement of soil quality by fertilization should be considered for stress reduction and improving the biomass quality in this type of soils.

Management and destruction of obsolete pesticides and the remediation of pesticide-contaminated soil are significant global issues with importance in agriculture, environmental health and quality of life. Pesticide use and management have a history of problems because of insufficient knowledge of proper planning, storage, and use. This manuscript reviews recent literature with an emphasis on the management of obsolete pesticides and remediation of pesticide-contaminated soil. The rhizosphere of plants is a zone of active remediation. Plants also take up contaminated water and remove pesticides from soil. The beneficial effects of growing plants in pesticide-contaminated soil include pesticide transformation by both plant and microbial enzymes. This review addresses recent advances in the remediation of pesticide-contaminated soil with an emphasis on processes that are simple and can be applied widely in any country.