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.

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.

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 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.