The importance of substrate compaction and chemical composition in the phytoextraction of elements by Pinus sylvestris L.

Trees of Scots pine (Pinus sylvestris L.) are known for their effective phytoextraction capabilities. The results obtained in this study point to the significant role of substrate composition and chemical characteristics in the phytoextraction potential of this species. A multi-elemental (53 elements) analysis of pines from unpolluted (soil) and polluted (post-flotation tailings) sites was performed using inductively coupled plasma optical emission spectrometry. The analyzed flotation tailings were characterized by alkaline pH (7.19 ± 0.06) and significantly higher conductivity (277.7 ± 2.9 µS cm-1) than the soil (pH = 5.11 ± 0.09; 81.3 ± 4.9 µS cm-1). The two substrates also differed with respect to the contribution of the clay fraction (0% in the unpolluted and 8% in the polluted substrate). The specimens of P. sylvestris growing on flotation tailings had significantly smaller height (381 ± 58 cm) and total aboveground biomass (4.78 ± 0.66 kg) than the trees growing in soil (699 ± 80 cm and 10.24 ± 2.10 kg). The biomass of the trunk, twigs and branches, and needles of the trees from polluted sites was between 40.0% and 48.7% of the biomass of the same organs of the control trees. Generally, the organs (trunk, twigs and branches, needles) of the P. sylvestris specimens from polluted sites had significantly higher concentrations of Au, Al, Ba, Cd, Co, La, Lu, Ni, Pd, Sc, Zn, and lower concentrations of B, Bi, Ca, Ce, Er, In, K, Mg, Na, Nd, P, Pr, Re, Se, Sr, Te than in the control plants, these metals being accumulated effectively in the whole of the aboveground biomass (BCF>1). Although the concentration of the majority of elements was significantly higher in the flotation tailings, significantly higher concentrations of these elements were observed in the tree organs from unpolluted sites, which points to the important role of substrate characteristics in the phytoextraction efficiency of P. sylvestris.

Establishment, Growth, and Yield Potential of the Perennial Grass Miscanthus × Giganteus on Degraded Coal Mine Soils.

Miscanthus × giganteus is a giant C4 grass native to Asia. Unlike most C4 species, it is relatively cold tolerant due to adaptations across a wide range of altitudes. These grasses are characterized by high productivity and low input requirements, making them excellent candidates for bioenergy feedstock production. The aim of this study was to investigate the potential for growing Miscanthus on extremely marginal soils, degraded by open lignite (brown coal) mining. Field experiments were established within three blocks situated on waste heaps originating from the lignite mine. Analyses were conducted over the first 3 years following Miscanthus cultivation, focusing on the effect of organic and mineral fertilization on crop growth, development and yield in this extreme environment. The following levels of fertilization were implemented between the blocks: the control plot with no fertilization (D0), a plot with sewage sludge (D1), a plot with an identical amount of sewage sludge plus one dose of mineral fertilizer (D2) and a plot with an identical amount of sewage sludge plus a double dose of mineral fertilizer (D3). Crop development and characteristics (plant height, tillering, and biomass yield [dry matter]) were measured throughout the study period and analyzed using Analysis of Variance (ANOVA). Significant differences were apparent between plant development and 3rd year biomass production over the course of the study (0.964 kg plant-1 for DO compared to 1.503 kg plant-1 for D1). Soil analyses conducted over the course of the experiment showed that organic carbon levels within the soil increased significantly following the cultivation of Miscanthus, and overall, pH decreased. With the exception of iron, macronutrient concentrations remained stable throughout. The promising yields and positive effects of Miscanthus on the degraded soil suggests that long term plantations on land otherwise unsuitable for agriculture may prove to be of great environmental and economic significance.