Potential of Energy Willow Plantations for Biological Reclamation of Soils Polluted by ¹³⁷Cs and Heavy Metals, and for Control of Nutrients Leaking into Water Systems

Abstract

Willow is a low-maintenance crop that has potential for energy production and enhancing the local environment. The area of commercial plantations of willow in Europe is mostly concentrated in Sweden, with more than 20 000 ha. Willow trees are used not only for energy production, but also for reclamation of polluted soils because a plantation may grow for 20–25 years, with a three-year period of harvesting. Our research covers issues of reclamation of soils contaminated by radionuclides and heavy metals, and decreasing of eutrophication of water ecosystems with using willow plantations. The field studies of phytoremediation of soil contaminated by 137Cs by willow plants were conducted in eastern Belarus, in the area where agricultural activity was banned after Chernobyl disaster. This region is heavily polluted with 137Cs (from 185 to 555 kBq/m2) and heavy metals. The transferring factors of accumulated 137Cs and heavy metals from the soil to willow biomass were determined. The field experiments showed that willow does not accumulate actively Cd and Pb, but it accumulates Zn, Cu and Mn intensively. The potassium application decreases the accumulation of 137Cs in willow biomass and increases accumulation of Cu, Zn and Mn, but has no influence on accumulation of Cd and Pb. Our results confirmed that soils polluted with radionuclide and heavy metals could be used for willow cultivation as energy crop, if adequate management is applied. The different potential of the willow species concerning heavy metals accumulation was also established. The yield of willow biomass on polluted soils achieved 11.5–12.8 DMg ha–1 per year, depending on variety, that is competitive with the ordinary yield of willow on mineral fertile soils. Willow plantations also may be used for accumulations of nutrients like nitrogen and phosphorus in watersheds. It enables to decrease impact for water ecosystems and to control eutrophication.

Ecological aspects of peat, straw, and wood ash application for energy willow cultivation

“…As a result, the ash had a positive effect on willow growing, especially in the second year after application (Table 3). In our experiment, the ash had a positive effect with dose application 1.0 and 1.5 mg dry mass ha -1 (Parka et al, 2005;Rodzkin et al, 2018;Rodzkin et al, 2019). Another study reported the positive effect of wood ash application on the soil acidity and the size of willow stems, but not on biomass production because the mean number of stems was significantly smaller in the ash-treated plots than in the control plots (Lazdina et al, 2011).…”

Patterns and driving factors of ecological stoichiometry in system of deadwood and soil in mountains forest ecosystem

“…Raw wood composed mainly of cellulose and lignin contains C in the amount of approx. 50%, while N and P in raw wood are only about 1.0–1.5% and 0.15–0.20% respectively 32 . The C:N:P proportions depend to some extent on the wood species 31 .…”

Untargeted metabolomics reveals anion and organ-specific biochemistry of salinity tolerance in willow

“…and willows (Salix sp. ), are common phytoremediation and biorefinery crops on marginal lands (Brereton et al, 2017;Dimitriou and Aronsson, 2005;Gonzalez et al, 2018;Rodzkin and Volk, 2018;Sas et al, 2021;Volk et al, 2006), with high potential for growth on salinised soils. For example, some cultivars can maintain transpiration and growth under saline conditions up to 6-8 dS m -1 (Bilek et al, 2020;Chen and Polle, 2010;Huang et al, 2020;Jerbi et al, 2020;Mirck andZalesny, 2015, 2015;Steppuhn et al, 2008).…”