Owing to the growing volumes of ash and sewage sludge waste, there is a requirement for theoretical and practical research into the use of these wastes as a source of nutrients. However, there are relatively few studies on the transfer of macronutrients in soil-plant systems amended with ash-sewage sludge mixtures under field conditions. The aim of the study was to determine the effect of bituminous coal ash (AC), biomass ash (AB), and municipal sewage sludge (MSS) on the quantity and quality of a grass-legume mixture. During a 6 year field experiment on a sandy loam soil treated with the wastes, applied as mixtures or separately, the plant yield; N, P, K, Na, Mg, and Ca uptake by plants; macronutrient content and ratios in the plant biomass; and the recovery rate of macronutrients by plants were evaluated. The AB-MSS treatment increased the yield in comparison to that where the wastes were applied separately. The N, P, and Ca contents in the plant biomass and N and P uptake under ash-sludge treatments were in the range observed for the ash and sewage sludge. The AB-MSS co-application resulted in the highest K uptake. The AC-MSS treatment increased K and Mg uptake in relation to AC treatment. When AC or AB was added to the MSS, the Ca uptake increased relative to the MSS treatment. The plant biomass under the AB treatment was optimal for biofuel purposes in terms of the chemical composition. The co-application of AC or AB with MSS resulted in the optimum Ca:Mg ratio for fodder purposes. The recovery rate of the macroelements decreased in the following order: K, N, P, Mg, Na, and Ca. The results support the co-application of solid wastes such as ash and municipal sewage sludge to improve productivity, support the recycling of macronutrients, improve sustainability through the reduction of ash and sewage sludge disposal, and reduce reliance on mineral fertilizer.

Gluten-free confectionery products were used as controls for comparison with the products, which included different supplements such as linseed meal, amaranth and/or buckwheat. The latter were expected to increase nutritional values of confectionery products. Cookies were analyzed in terms of volume, selected textural parameters (hardness, cohesiveness), organoleptic quality, shelf-life, and different chemical components. All supplemented gluten-free products received high consumer scores, exceeding in some cases those of control samples. Supplementation of gluten-free confectionery products with linseed meal, amaranth and/or buckwheat flours enhanced their final nutritional quality. A significant rise was observed in the protein content and dietary fiber, and in the case of linseed meal also α-linolenic acid. All of the supplemented gluten-free confectionery products contained more macro-elements and micro-elements (i.e. potassium, phosphorus, magnesium, calcium, iron, manganese, zinc and copper), as compared with the controls. Taking into account the amino-acid composition, amaranth proved a more beneficial supplement of gluten-free products than linseed.

Differences in soil quality indices, in terms of the inherent properties of loess parent material and the potential for Zn, Pb and Cd contamination from the emissions of an adjacent large industrial complex, were determined. A set of independent variables was established for the soils, using principal component analysis (PCA) and a random forest (RF) method. The quality indices of 140 topsoil samples from the environs of an industrial complex were compared with those of reference soils taken from around the borders of the study area. Potential driving factors for the Zn, Pb and Cd concentrations were dehydrogenase activity (DHA), urease (Ure) activity and invertase activity (IA), C, N, K₂O, MgO, P₂O₅ and soil clay content. Maps were generated to show the spatial distributions of the Zn, Pb and Cd contamination. Enrichment factors and potential ecological risks were calculated. We established that, in general, concentrations of Zn, Pb and Cd in the topsoil decreased with increasing distance from the industrial complex, and the levels of Zn and Cd exceeded established intervention values, even in some soils on arable land. The arable land was enriched in P₂O₅, while the highest values for K₂O and MgO were found in wasteland soils. The mean C content of all the soils was about 2%, with N (about 0.2%), C/N ratio (about 12) and pH (about 6.9) in the order: arable land<meadow<wasteland. The highest DHA and Ure activity was determined in the reference (unpolluted) soils, while much higher IA was present in the wasteland soils. PCA model focused on factors connected with different soil uses, while RF model emphasised the natural resistance of the studied soils to degradation. Our results indicate that the driving factors of the soil quality index were controlled by the inherent properties of the loess parent material, rather than soil pollution.