Biochar-Assisted Phytostabilization for Potentially Toxic Element Immobilization

In response to the growing threat to the quality of the soil environment, new technologies are being developed to protect and remediate contaminated sites. A new approach, namely, assisted phytostabilization, has been used in areas contaminated with high levels of potentially toxic elements (PTEs), using various soil additives. This paper determined the effectiveness of biochar-assisted phytostabilization using Dactylis glomerata L. of soil contaminated with high concentrations of the selected PTEs (in mg/kg soil): Cu (780 ± 144), Cd (25.9 ± 2.5), Pb (13,540 ± 669) and Zn (8433 ± 1376). The content of the selected PTEs in the roots and above-ground parts of the tested grass, and in the soil, was determined by atomic absorption spectrometry (AAS). The addition of biochar to the contaminated soil led to an increase in plant biomass and caused an increase in soil pH values. Concentrations of Cu, Cd, Pb and Zn were higher in the roots than in the above-ground parts of Dactylis glomerata L. The application of biochar significantly reduced the total content of PTEs in the soil after finishing the phytostabilization experiment, as well as reducing the content of bioavailable forms extracted from the soil using CaCl2 solution, which was clearly visible with respect to Cd and Pb. It is concluded that the use of biochar in supporting the processes of assisted phytostabilization of soils contaminated with PTEs is justified.

Aerenchyma Formation in Adventitious Roots of Tall Fescue and Cocksfoot under Waterlogged Conditions

The formation of aerenchyma in adventitious roots is one of the most crucial adaptive traits for waterlogging tolerance in plants. Pasture grasses, like other crops, can be affected by waterlogging, and there is scope to improve tolerance through breeding. In this study, two summer-active cocksfoot (Dactylis glomerata L.) cultivars, Lazuly and Porto, and two summer-active tall fescue (Lolium arundinaceum Schreb., syn. Festuca arundinacea Schreb.) cultivars, Hummer and Quantum II MaxP, were selected to investigate the effects of waterlogging on root growth and morphological change. Cultivars were subjected to four periods of waterlogging treatments (7, 14, 21 and 28 days), while comparable plants were kept under free drained control conditions. The experiment was arranged as a split–split plot design, with waterlogging treatments (waterlogged, control) considered as main plots, time periods (days of waterlogging) as subplots and cultivars as sub-subplots. Plants began to show signs of waterlogging stress 14–21 days after the onset of waterlogging treatments. There were no significant differences in shoot biomass between the waterlogged and control plants of any cultivar. However, waterlogging significantly reduced root dry matter in all cultivars, with greater reduction in cocksfoot (56%) than in tall fescue (38%). Waterlogging also led to increased adventitious root and aerenchyma formation in both species. Cocksfoot cultivars showed a greater increase in adventitious roots, while tall fescue cultivars had a greater proportion of aerenchyma. Both cultivars within each species showed similar responses to waterlogging treatments. However, an extended screening program is needed to identify whether there are varietal differences within species, which could be used to discover genes related to aerenchyma or adventitious root formation (waterlogging tolerance) for use in breeding programs.

Recycling of Blast Furnace and Coal Slags in Aided Phytostabilisation of Soils Highly Polluted with Heavy Metals

(1) Background: The growing demand for developing new methods of degraded land remediation is linked to the need to improve the soil environment, including post-industrial soils. Biological methods such as the aided phytostabilisation technique are the most common methods applied to achieve effective remediation. This study aimed to determine the technical potential of methods using novel or yet not used soil amendments, such as blast furnace slag (BFS) and coal slag (CS), with Dactylis glomerata L. as a test plant. (2) Methods: The experiment was conducted on post-industrial area soil with high concentrations of Cu (761 mg/kg), Cd (23.9 mg/kg), Pb (13,539 mg/kg) and Zn (8683 mg/kg). The heavy metal content in roots and the above-ground parts of plants and soil was determined by flame atomic absorption spectrometry. (3) Results: The addition of BFS to the soil was the most effective in increasing Dactylis glomerata L. biomass yield. The Cu, Cd, Pb, and Zn concentrations were higher in the roots than in the above-ground parts of the plants. BFS and CS induced a considerable increase in soil pH, compared to the control treatment. The addition of BFS also produced the greatest significant decrease in the Pb content in soil following the phytostabilisation process. (4) Conclusions: In view of the above, the use of BFS in the aided phytostabilisation in soils contaminated with high levels of Cu, Cd, Pb, and Zn can be recommended for larger-scale in situ projects.

Agronomic Evaluation of the Results of Selection within Late-Maturing Dactylis glomerata Populations

Selection from novel orchardgrass (Dactylis glomerata L.) germplasm sources resulted in the development of a late-maturing orchardgrass population. This population comprises 58 families that were evaluated with 5 commercial cultivars under frequent and infrequent harvest intervals at two Cache County, UT, USA field locations during 2013 and 2014. The objective of this study was to characterize the performance of individual families when compared to check cultivars Intensive and Latar. Across locations and harvest intervals, individual families produced greater herbage dry mass and nutritive value than the check cultivars did, i.e., up to 12% greater herbage dry mass than that of the highest check, Intensive, and 1% (neutral-detergent-fiber digestibility) to 14% (water soluble carbohydrates) greater forage quality than that of the corresponding highest check cultivar. However, there were substantial genotype-by-environment interactions between families and locations, but not harvest intervals. Because of this, results were analyzed across harvest intervals but within locations. Within each location, there were families that possessed similar or greater maturity, herbage dry mass, in vitro true digestibility, and neutral-detergent-fiber digestibility at both locations. Overall, on the basis of the performance of its component families, this late-maturing orchardgrass population exhibited potential for developing improved cultivars.

Uptake and Utilization of Nitrogen from Organic Fertilizers Influenced by Different Doses of Copper

Copper is a microelement involved in the metabolism of nitrogen compounds in plants. Good utilization of nitrogen from soil and fertilizers by plants requires an adequate supply of copper. The aim of the study was to determine the effect of increasing levels of copper (100, 200, and 300 mg Cu·kg−1 of soil) applied together with various organic fertilizers (cattle manure, chicken manure, and spent mushroom substrate) on nitrogen content and uptake by cocksfoot (Dactylis glomerata L.) and the coefficient of nitrogen utilization from organic fertilizers. The pot experiment was carried out in three growing seasons (May–September) in greenhouse, and in this cocksfoot was grown and harvested four cuts in each year. Copper and organic fertilizers were applied once in the first year before sowing cocksfoot, and the after-effect was investigated in the second and third years. Application of different amounts of copper did not influence the nitrogen content in the biomass of cocksfoot. At the same time, soil application of this micronutrient in the amount of 100 mg Cu∙kg−1 of soil caused an increase in nitrogen uptake in the biomass of cocksfoot. Application of 100 and 200 mg Cu·kg−1 of soil caused an increase in the coefficient of nitrogen utilization from the organic fertilizers, which was highest effect in the case of cattle manure. All of the organic materials used increased the content of nitrogen and its uptake by cocksfoot, but the greatest effect was noted following application of chicken manure. The study showed no synergistic or antagonistic relationships between copper and nitrogen.

Substantiation of the basic constructive-and-technological parameters of technology for preparing haylage of the cocksfoot (Dactylis glomerata L.) using gas preservative

The most important task for the further development of animal breeding is increase of production of feed, increase of its quality and reduction of production costs. Important thing in these conditions is the parallel development of two areas - creation of highly productive agrocenoses and development of technologies capable of saving the obtained feed mass for future use during winter period. A valuable component in grass mixtures when creating highly productive hayfields in the North-West region is the cocksfoot (Dactylis glomerata L.), which in the North conditions forms rather high yield of feed mass, as soon as it responds to fertilizer application properly. On the basis of the Institute of Agrobiotechnology Federal Research Center Komi Scientific Center Ural Branch of the Russian Academy of Sciences (Russia, Komi Republic, Syktyvkar), a device has been developed for treating haylage by carbon dioxide. To determine the efficiency of this technique when harvesting haylage of cocksfoot, two series of experiments were carried out - laboratory and field. In the course of the laboratory experiment, we conducted an experiment according to the Box-Behnken plan of the second order for four factors with three levels of variation. The optimal parameters of the device were determined as a result: density of raw materials; volume of raw material processed by one spray nozzle; gas preservative consumption and its dose. In the field experiment, haylage was processed in rolls according to certain optimal parameters. The feed obtained was compared in terms of quality with haylage prepared of the same raw material in compliance with standard technology, but with no preservatives. As a result of the studies, it has been determined that carbon dioxide is most effective when harvesting the cocksfoot as raw material for haylage, with the following parameters: density of pressing the hay mass - 290-330 kg/m3 ; moisture content of raw materials - 53-55 %; dose of carbon dioxide introduced into the haylage - (0.40-0.50)∙10-3 m3 /kg; carbon dioxide consumption through a gas supply reducer 0.500.60 m3 /h. This provides an increase in feed units in one kilogram of feed by 0.3, exchange energy - by 0.4 MJ, digestible protein - by 1 g.