In the current study, we have examined the possibility to improve the biocompatibility of the (TiZrNbTaHf)C through replacement of either Ti or Ta by Si. The coatings were deposited on Si and 316L stainless steel substrates by magnetron sputtering in an Ar+CH4 mixed atmosphere and were examined for elemental composition, chemical bonds, surface topography, surface electrical charge and biocompatible characteristics. The net surface charge was evaluated at nano and macroscopic scale by measuring the electrical potential and work function, respectively. The biocompatible tests comprised determination of cell viability and cell attachment to the coated surface. The deposited coatings had C/(metal+Si) ratios close to unity, while a mixture of metallic carbide, free-carbon and oxidized species formed on the film surface. The coatings’ surfaces were smooth and no influence of surface roughness on electrical charge or biocompatibility was found. The biocompatible characteristics correlated well with the electrical potential/work function, suggesting a significant role of surface charge in improving biocompatibility, particularly cell attachment to coating's surface. Replacement of either Ti or Ta by Si in the (TiZrNbTaHf)C coating led to an enhanced surface electrical charge, as well as to superior biocompatible properties, with best results for the (TiZrNbSiHf)C coating.

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Willow (Salix) family is one of the fastest-growing woody energy crops. It·has been widely used for biomass energy production in short-rotation plantations, carbon storage in longer rotation, and as a phytoremediation plant in Northern Europe. Willows could be cultivated on a wide range of soils, including marginal land, and they are readily propagated by planting un-rooted cuttings. Soil fertilization is necessary for obtaining a higher biomass yield. Different side products of energy production and municipal waste could be used for soil improvement. The aim of this research is to review fertilization practices in short-rotation willow plantations and their impact on the biomass yield. The data from the literature were collected, and different doses of various fertilizers were compared. The response to fertilization is positive if fertilizer contains complex NPK macro elements. The most appropriate dose per hectare varies depending on the soil properties, soil types, willow varieties, weather conditions, water availability, and other factors. Wood ash and peat could be used for soil improvement to solve the main characteristic marginal soils problems in Latvia – low organic content and pH value. Wood ash has high concentrations of calcium (Ca) and magnesium (Mg) and already is widely used as a liming agent in organic farming. Less demanded peat fractions, dewatered wastewater sludge, and biogas fermentation leftover -digestate contain a high amount of organic matter and nitrogen, therefore, could be used as a replacement for previously used fertilizers such as cattle slurry. In addition, wastewater sludge, digestate, and wood ash are also sources of microelements. A mix of all listed products has a high potential to be used as a complex soil amendment.

In the context of climate change, it is necessary to establish forest management by balancing more products, using less area, and minimizing environmental impacts. The use of different industrial bio-based by-products as soil conditioners in the last few decades has gain more interest, because it leads to an extended use time of these products and supports the circular economy. The aim of this study was to determine the effect of fertiliser made from cattle and pig manure biogas fermentation digestate and wood ash from two cogeneration plants, applied in different mixture ratios, to test its suitability for fertilisation of deciduous trees, using the physiological, morphological, and chemical parameters of the leaves as an indicator. We selected two poplar clones: foreign ‘OP42’ (syn. Hybrid 275) and local ‘AUCE’ annual shoot stem cuttings as planting materials. A negative control group with acidic forest mineral soil as substrate and four fertilised groups with different applied digestate and wood ash ratio mixtures to forest soil was established (ash:digestate 0:0 (Control), 1:1, 2:1, 3:1, 4:1). Mixture application improved growing conditions because all fertilised group poplars had longer growth periods and photosynthetic rates in August than the control group. Both local and foreign clones showed a good response to fertilisation in terms of leaf parameters. Poplar is a suitable culture to fertilise with bio-waste biogenic products, because of its capacity to absorb nutrients and fast response to fertilisation.

The selection of most suitable propagation material, as well as the adjustment of existing seedling management practices, are gaining increasing importance to ensure the best outcomes under the long-term setting of climate change. One of the factors to consider is a predicted increase in the frequency and duration of high-temperature periods. Since heat often coincides with drought, these factors are typically assessed together, yet heat stress on its own has received less attention. In this study, we examined the effect of supra-optimal ambient temperature on nine Salix alba clone cuttings wilting under greenhouse conditions and sufficient moisture levels. Most plants are especially vulnerable to extreme conditions in early stages of development. Response to heat varied between clones but, overall, shoots that were taller than 350 mm were more sensitive to heat stress. The pruning of excess lateral shoots did not show significant improvement in heat tolerance. In total, 96% of the wilted cuttings proceeded to produce lateral shoots after the cessation of heat stress. It should be studied further if similar patterns are evident in field conditions and if earlier outplanting has a positive effect on cutting vitality.