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The fertilizer values of ashes from commonly used woody species in the tropics are not well-known. To determine whether ashes of Theobroma cacao, Persea americana, Cola nitida, Mangifera indica, Citrus sinensis, Prunus dulcis, and Senna siamea are suitable fertilizers, we studied the contents of total and plant-available elements. Ashes of dry wood samples burnt at 500 °C were digested in Aqua-regia and Mehlich-3 extractants to determine the contents of total and plant-available elements, respectively, with inductively coupled plasma-mass spectrometry. Ash yields ranged from 3.1 to 7.1% with pH (H2O) of 7.8–12.9. The ashes contained high P, Ca, K, Mg, S, Fe, Na, Mn, Cu, and Zn contents, with significant effects among the species. Total element content ranged from (g kg−1) 2–49 P, 19–218 Ca, 64–325 K, 48–95 Mg, 0.4–16 Fe, 3.6–29 Na, (mg kg−1) 143–798 Mn, 52–81 Cu, and 188–312 Zn. Available plant elements ranged from (mg kg−1) 22–512 P, 37,491–88,303 K, 2948–19,713 Ca, 13,719–29,001 Mg, 75–168 Mn, 40–74 Cu, 44–91 Zn, 1.5–383 Fe, and 836–6937 Na. The releasability (proportion of plant-available elements from the total) ranged from 0.08 to 92.8%. The relatively high releasability (25.4–80.4%) of Ca, K, Mg, Mn, Cu, and Zn in the ashes of the over-all species can supplement low nutrient availability for plants. The low releasability of P (1.1%) of the overall species explains its persistence in soils applied with ashes. The high yield of the ashes and pH support their ideal use, especially for very acidic soils. Ashes of the studied species are suitable fertilizers for soils according to the availability and releasability of macro(P, Ca, K, Mg S) and microelements (Mn, Cu, Zn, Fe, Na). Total and plant-available Ni, Pb, As, and Cd contents in the ashes were below permissible limits in soils. Thus, the studied ashes are especially suitable for soils with high acidity and low fertility.

The analysis of minor/microelements in anthropogenic soils resulting from past settlement activities in different environmental conditions and geographical regions is not well-known. The study aimed to determine whether minor/microelements are suitable proxy indicators of past human activities of Archaeological Dark Earth (ADE) soils from two past hilltop settlements- Ziavi-Galenkuito in Ghana and Dřevic hillfort, Czech Republic. Total and plant-available (Mehlich 3) contents of minor/microelements were determined using portable X-Ray Fluorescence spectrometry and Inductively coupled plasma mass spectrometry, respectively. The black color of the soils from Ziavi-Galenkuito and Dřevic hillfort contrasted the brownish Ferric Acrisol and greyish Luvic Cambisol control, respectively. The contents of total and plant-available Cu, Zn, Mn, Sr, and total Rb was substantially higher in both sites compared to their control of the same geological substrates. The highest total and plant-available Mn content in Ziavi-Galenkuito may indicate specific intensive settlement activities in a comparatively shorter duration. The highest total Cu, Zn, Sr, and Rb content in the soil from Dřevic hillfort compared to Ziavi-Galenkuito related to longevity and intensity of the past human activities. Total Cu, Zn, Mn, and Sr can well reflect past human activities from different geographical regions according to their significant correlations from both studied sites. Except for Mn and Sr, total and plant-available content of Cu and Zn were not well correlated. Except for Mn and Sr, total and plant-available content of Cu and Zn were not well correlated. In the calculation of enrichment factors in ADE soils for geoarchaeological purposes, total Mn, Cu, Zn, and Sr are more suitable. Enrichment by minor/microelements can be reliable enough in predicting past human activities in ADE soils of different geology and climatic conditions, even after hundreds of years.

Archaeological Dark Earth soil is a category of archaeological anthrosols that has gained much attention because it exhibits higher nutrient content and organic matter stocks and a characteristic dark colour, and enables higher crop yields in comparison to neighbouring soil. However, much is unknown about the chemical properties of Archaeological Dark Earth soils in Central Europe. Therefore, we studied a European Dark Earth (EDE) soil, a type of Archaeological Dark Earth soil, in the territory of the early medieval Dřevic hillfort, Czech Republic, aiming to compare the chemical properties of EDE with a control soil unaffected by settlement activities. The black colour of EDE soil contrasted highly with the light grey Cambisol of the control. Soil reaction and total element contents (N, P, Ca, Mn, Fe, Al, Cu, Zn, Sr and Rb) were substantially larger in the EDE soil compared with the control and vice versa in the case of the C/N ratio. Also, the content of plant‐available (Mehlich III) P, Ca, K and Mg was larger in the EDE soil than the control. In contrast to Ca, plant‐available and total P and K were not well correlated. Total element contents are highly suitable for geoarchaeological purposes as enrichment factors can be easily calculated. The increased contents of these elements, together with pieces of charcoal visible in the EDE soil, indicate the deposition of organic waste and biomass ash during the existence of the hillfort. Thus, medieval hillforts can represent extraordinary nutrient‐rich islands in the cultural landscape of Central Europe. The chemical signatures generated by past settlement activities are so intense that they cannot easily be masked by short‐term intensive application of mineral fertilizers. HIGHLIGHTS: Settlement activities increased soil pH and the content of anthropogenic elements. Enrichment by P, Ca, Mn, Fe, Al, Zn, Cu, Sr and Rb may indicate settlement activities. Analysis of total element contents is suitable for geoarchaeological purposes. Application of mineral fertilizers cannot easily mask signatures of medieval settlement activities.

The socio-economic needs of ancient societies before the onset of the industrial revolution thrived the exploitation of metals, with resultant adverse effects on the chemical signatures of soils. So far, there are no studies that summarize the contamination of soils by metals due to mining and metallurgy before the industrial revolution (c. 1800 century AD). The article presents an overview of soil contamination by metals due to ancient (prehistory up to the end of medieval period) mining and metallurgy, the global distribution of metal exploitations, the effects on soils and lives, as well as their speciation and bioavailability. The study established that the concentrations of Cu, Ag, Pb, Hg, and Zn were substantially higher in the soils affected by ancient mining and metallurgy in comparison to background values, eventually causing harm to ecosystems after centuries without mining and metallurgy. The concentrations of the metals subsequently are bioaccumulated in recent fields. Understanding the persistence, distribution, and bioavailability of the metals is pertinent in selecting suitable remediation techniques for contaminated soils from ancient mining and metallurgy sites. Even after centuries without mining and metallurgy in ancient sites, the long-term fate of metal contaminations in soils is detectable. The still-unsolved question is the level of metals available and releasable from the total content to plants, especially on arable fields of previous mining and metallurgy sites and their surroundings. Contemporary effects of past mining and metallurgy on contamination of soils provide relevant information on the current and future implications of recent metalliferous activities.

How long decomposed buried human bodies affect soil elemental composition is so far not well-known. Using portable X-ray fluorescence spectrometry, we determined the elemental composition of sandy necrosols from a Corded Ware Culture (ca 2800–2500 BCE) graveyard, Chudeřin, Czech Republic. The elemental compositions of soils in the grave infills were studied and compared with arable and subsoil layers. After removal of the arable layer, infills of graves were identified by the black color in contrast with their reddish surroundings. The burials affected the content of elements even after more than 4500 years. Increased C contents compared with arable and subsoil layers were recorded only close to bones. The lowest P content was in grave infill, where soft tissues decomposed, because of P leaching. Therefore, increased P content in the infill of the prehistoric graves mentioned by previous authors is not a reliable indicator of soft tissue decomposition. In the acidic environment, P and Ca released from bones partly fixed in the grave infill ≤ 5 cm to bones. The high contents of P and Ca in bones and soils close to bones were a source of these elements for plants, indicated by a high density of fine roots. The highest contents of trace elements (Mn, Cu, As, and Pb) were in the arable layer because of recent disposition. The most reliable soft tissue decomposition indicator was an increased Zn content in the grave infill. The multi-elemental analyses of prehistoric necrosols were neglected so far and require further detailed research as the chemical signatures are well-preserved for millennia.

Archaeological Dark Earth (ADE) is a layer of anthrosol (syn. anthroposol) visually characterized by dark color mainly due to homogenous charcoal inclusion, and substantial enrichment by nutrients in comparison to surrounding soils. ADE is distributed from the tropics (Amazonian Terra preta, African ADE), moderate climatic zones (European ADE) up to the Arctic (kitchen middens). Although ADE soils have been studied also in other regions of the world, they have no special regional names. All types of ADE developed as a result of deliberate and/or unintentional deposition of domestic/occupational wastes, charred residues, bones, shells, and biomass ashes from prehistoric up to recent times. ADEs have optimum C : N ratio for effective mineralization, stable organic matter content, reduced acidity, higher CEC and C, N, P, Ca, Mn, Cu, Zn, Mn, Mg, Fe, Sr, and Ba content in comparison to surrounding soils. The unclear remains the level of ADEs enrichment by these elements as enrichment factors for different elements are based on different analytical approaches from plants-available up to total contents in the soil. Although generally highly productive, comparison of herbage production and crop yields between ADEs and natural soils are still rare. The distribution and persistence of anthropogenic activities leading to the formation of ADEs indicate that they are subject to the continual formation.

Past settlement sites are associated with the accumulation and depletion of many elements. The effects of past settlement activities on recent arable land-use are not well known. The study aimed to determine the effect of past human activities on contemporary arable soil according to the physical and chemical properties and magnetic susceptibility. We studied anthroposols developed on metamorphic maritime sediment of Proterozoic age in an Early Medieval to 1945 settlement, Běla nad Radbuzou, Czech Republic. The study compared the anthroposols with surrounding control of the same geological substrate unaffected by past settlement activities. The originally brown Luvic Cambisol in control turned black in the settlement site mainly due to the decomposition of organic wastes and partly from charcoal inclusion, with a high proportion of clay. The anthroposols additionally were characterized by reduced acidity and higher accumulation of total (P, K, Ca, Mg, Mn, Fe, Cu, Zn, Sr, and Rb) and plant-available (mehlich-3 P, K, Ca, Fe, Cu, and Zn) elements compared to the control. Furthermore, anthropogenic stress was well recorded by the magnetic susceptibility of soil from the anthroposols, with a significant correlation to the Ca, Mn, Cu, Zn, and Pb. Magnetic susceptibility can, therefore, be a suitable proxy indicator for past settlement activities. The comparatively lower releasability (proportion of elements available for plants from the total content) of P, Ca, Cu, and Zn in the settlement site explains why their signatures in archaeological localities are very stable and long-lasting. Total P correlated well with total K, Ca, Mn, Fe, Cu, Zn, and Rb, rendering them suitable indicators of past human settlement activities. Past settlement activities on contemporary arable soils can be reflected by high elemental composition and magnetic susceptibility, even after many years.

Can less than a hundred years of past settlement activities in former European settlements substantially increase the concentration of elements and result in the formation of African Dark Earth soil is a question not addressed. We performed multi–element analysis of Africa Dark Earth soil from a late 19th to mid–20th century CE former German–Togoland settlement, Ziavi–Galenkuito in the Volta Region, Ghana. Relatively neutral reaction and black color of soil mainly from charcoal inclusion in the settlement site contrasted highly with moderately acidic brown Ferric Acrisol in the control located on the same metasedimentary/Voltaian bedrock. Organic C and total N, P, K, Ca, Mn, Fe, Cu, Zn, Sr and Rb concentrations were substantially increased and vice–versa for the C/N ratio in the 0–40 cm layer of the settlement soil compared to the control without settlement activities. The concentrations of plant–available P, K, Ca, S, Fe, Cu and Zn were higher in the settlement soil in comparison to the control. The increased concentrations of the elements mentioned above resulted in the disposition of organic waste and biomass ash. Significantly higher concentrations of total and plant–available elements in 0–10, 10–20 and 20–40 cm layers of settlement site compared to their respective control suggested that chemical signatures from past settlement activities can be determined even in the upper soil layer. Positive correlations between the concentration of P and K, Mn, Sr, Fe, Ca, Zn, Rb, Cu implied that these elements were indicators of past settlement activities. The concentrations of total and plant–available P, K, Ca, Fe, Cu and Zn were well correlated; however, total elements concentrations are much suitable for geoarchaeological purposes as it is easy to calculate enrichment factors. We concluded that intensive human settlement activities in even