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.

The objective of the study was to examine the structure of typical Ukrainian chernozem developed on loess, which (I) had been fertilized by standard crop rotation since 1912 with farm yard manure at the rate of 16 t ha-1 and (II) had not been fertilized with farm yard manure by sugar beet monoculture since 1929. After harvest of winter wheat and sugar beet, the samples of undisturbed structure were taken from 5 layers of both profiles: 0-8, 10-18, 20-28, 30-38, and 40-48 cm. The morphological analysis of the structure of the investigated chernozem revealed that the most visible differences between the soil structures of the two pedons occurred in their superficial layers. The 0-18 cm layer of the soil in the experiment I had an aggregate structure, whereas analogous layer of the soil in experiment II was much more compacted. Below about 30 cm from the ground level both pedons had very similar structure. For the soil in the experiment I an appropriate crop rotation and regular supplies of organic matter allowed for preservation of a favourable structure even in the upper layers - in contrast to the soil in the experiment II.