Silicon Mobilization in Soils: the Broader Impact of Land Use

Dissolved Si (DSi) provision from land systems triggers diatom growth and CO2 sequestration. Soils and ecosystems act as a Si “filter”, transforming DSi originated from mineral weathering into biogenic Si (BSi) after DSi uptake by plants, or into other pedogenic forms of Si (non-BSi). Land use changes the quantity of BSi and non-BSi pools along the soil profile. However, methods used to isolate Si pools include chemical extractions at high temperatures and alkaline environments and therefore are unable to provide information concerning the dissolution potential of BSi and non-BSi pools under normal conditions of temperature and pH. Here, we conducted a batch experiment where forest, pasture and cropland soil samples were mixed with water at 25 °C and pH 7. The soil samples were collected from a temperate land use gradient located in the Belgian Loess Belt. We measured dissolved Si and aluminium (Al) during 80 days. BSi and non-BSi pool contents along the soil profile were known, as they had been established previously through chemical extraction. Results show that BSi and non-BSi enriched samples present distinct Si and Al dissolution curves. While non-BSi pools contribute significantly with immediate availability of Si, BSi pools present an initial slow dissolution. Therefore, croplands that were depleted of phytoliths and had poorly organic horizons display higher concentrations of initial dissolved Si, while pastures and forests, where pedogenic pools dominate only at depths below 40 cm, have more limited initial Si release.info:eu-repo/semantics/publishedVersio

Ainu Prayer Text Asahikawa Ainu\u27s prayer (published in the KAMIKAWA Ainu Kumamatsuri )

欧文抄録:p.256These texts were told by Tuakanno SUNAZAWA,Nankeainu MONNO,Hautomtei MONNO, Atsumiyashikuru ISHIYAMA, and recoded by Hideaki KURAMITSU in city MONBETSU in Hokkaido on October.25, 1953. 30 prayers texts upon Bear ceremony(iomante) in Ainu northern diaIect (Ishikari dialect). Roman transcription.1. Prayer to the fire goddess 2.Prayer to the fire goddess 3.Tapkar dance 4.Prayer to the fire goddess 5.Prayer to the fire goddess 6.Prayer to the guardian of village 7.Prayer to the guardian of village 8.Prayer to the god of forest 9.Prayer to the god of wolf 10.Prayer to the god of fox 11.Prayer to the god of owl 12.Prayer to the god of bear 13.Prayer to the god of cliff 14. Prayer to the god of altar 15.Prayer to the god of altar 16.Prayer to the god of wren 17.Prayer to the god of waesel 18.Prayer to the Siberian black bellied dipper 19.Prayer to the water goddess 20.Prayer to the god of pile 21.Prayer to the god of pile 22.Prayer to the cubs 23.Prayer to the cubs 24.Prayer to the cubs 25.Prayer to the god of heaven 26.Prayer to the god of bear 27.Prayer to the cubs 28.Prayer to the god of bear 29. Prayer to the god of bear 30.Tapkar dance 31. Tapkar dance 32.Prayer to the fire goddess 33.Prayer to the cub

Amorphous Silica Preservation in an Anthropogenic Soil: An Explorative Study of "Plaggen" Soils

Amorphous Silica (ASi) is present in considerable amounts in most soils and serves as a (micro-)nutrient for many plants. However, our understanding of the response of this important nutrient pool to human or natural disturbances is still very limited. One of the reasons for this is the long time scales involved. This explorative study focuses on the effect of a historical agricultural system, called plaggen management, that was applied on sandy areas in Belgium, the Netherlands and Germany over a period of ca. 1000 yrs on ASi dynamics. The system was designed to maintain high nutrient levels (including C and Si) on arable fields through the addition of mixtures rich in animal manure and vegetation residues. The continuous addition of ASi over such a long time period allows to study if and to what extent ASi is preserved in such a soil system and how Si addition affects the build-up and availability of ASi pools. We quantified ASi pools (Na2CO3 extraction) in a soil profile with plaggen application, and a reference soil without plaggen application. Other measured soil properties were soil organic carbon (SOC) and grain size distribution. There was an important SOC (+20%) and ASi accumulation (+70%) and preservation at the plaggen site. Si losses from the soil column through leaching and crop harvest might thus be restricted by application of organic residue and Si fertilisation to maintain sustainable nutrient concentrations in the topsoil. Net C and Si accumulation rates were 45 kg C ha(-1) y(-1) and 77 kg SiO2 ha(-1) y(-1) respectively, not accounting for the removal of ASi through plant uptake nor for the mineralisation of part of the SOC. The vertical distribution of ASi within the profile, suggests that, contrary to SOC, most of the added ASi has remained stably stored in the soils and that only a smaller, labile pool was removed, most likely through dissolution rather than through plant uptake. Our results indicate that ASi addition leads to a build-up of Si pools in these sandy soils. While this results in increased Si availability, this effect is limited because most ASi remains stored for long time spans. To consolidate our preliminary research results, to answer unresolved questions and to validate proposed hypotheses, future research should: (I) collect additional profiles with higher vertical resolution; (2) include other Si fractions; (3) analyse the relationship between ASi and SOC to better understand the coupling of the ASi and C cycles; (4) develop a modelling approach that would allow one to investigate how ASi pools in soils may respond to future changes

Amorphous silica preservation in an anthropogenic soil : an explorative study of "plaggen" soils

Amorphous Silica (ASi) is present in considerable amounts in most soils and serves as a (micro-)nutrient for many plants. However, our understanding of the response of this important nutrient pool to human or natural disturbances is still very limited. One of the reasons for this is the long time scales involved. This explorative study focuses on the effect of a historical agricultural system, called plaggen management, that was applied on sandy areas in Belgium, the Netherlands and Germany over a period of ca. 1000 yrs on ASi dynamics. The system was designed to maintain high nutrient levels (including C and Si) on arable fields through the addition of mixtures rich in animal manure and vegetation residues. The continuous addition of ASi over such a long time period allows to study if and to what extent ASi is preserved in such a soil system and how Si addition affects the build-up and availability of ASi pools. We quantified ASi pools (Na2CO3 extraction) in a soil profile with plaggen application, and a reference soil without plaggen application. Other measured soil properties were soil organic carbon (SOC) and grain size distribution. There was an important SOC (+20%) and ASi accumulation (+70%) and preservation at the plaggen site. Si losses from the soil column through leaching and crop harvest might thus be restricted by application of organic residue and Si fertilisation to maintain sustainable nutrient concentrations in the topsoil. Net C and Si accumulation rates were 45 kg C ha(-1) y(-1) and 77 kg SiO2 ha(-1) y(-1) respectively, not accounting for the removal of ASi through plant uptake nor for the mineralisation of part of the SOC. The vertical distribution of ASi within the profile, suggests that, contrary to SOC, most of the added ASi has remained stably stored in the soils and that only a smaller, labile pool was removed, most likely through dissolution rather than through plant uptake. Our results indicate that ASi addition leads to a build-up of Si pools in these sandy soils. While this results in increased Si availability, this effect is limited because most ASi remains stored for long time spans. To consolidate our preliminary research results, to answer unresolved questions and to validate proposed hypotheses, future research should: (I) collect additional profiles with higher vertical resolution; (2) include other Si fractions; (3) analyse the relationship between ASi and SOC to better understand the coupling of the ASi and C cycles; (4) develop a modelling approach that would allow one to investigate how ASi pools in soils may respond to future changes

Silicon mobilization in soils : the broader impact of land use

Dissolved Si (DSi) provision from land systems triggers diatom growth and CO2 sequestration. Soils and ecosystems act as a Si “filter”, transforming DSi originated from mineral weathering into biogenic Si (BSi) after DSi uptake by plants, or into other pedogenic forms of Si (non-BSi). Land use changes the quantity of BSi and non-BSi pools along the soil profile. However, methods used to isolate Si pools include chemical extractions at high temperatures and alkaline environments and therefore are unable to provide information concerning the dissolution potential of BSi and non-BSi pools under normal conditions of temperature and pH. Here, we conducted a batch experiment where forest, pasture and cropland soil samples were mixed with water at 25 °C and pH 7. The soil samples were collected from a temperate land use gradient located in the Belgian Loess Belt. We measured dissolved Si and aluminium (Al) during 80 days. BSi and non-BSi pool contents along the soil profile were known, as they had been established previously through chemical extraction. Results show that BSi and non-BSi enriched samples present distinct Si and Al dissolution curves. While non-BSi pools contribute significantly with immediate availability of Si, BSi pools present an initial slow dissolution. Therefore, croplands that were depleted of phytoliths and had poorly organic horizons display higher concentrations of initial dissolved Si, while pastures and forests, where pedogenic pools dominate only at depths below 40 cm, have more limited initial Si release.info:eu-repo/semantics/publishedVersio

Factors controlling Si export from soils: A soil column approach

The release of dissolved silicon (DSi) from A and B horizons was investigated with leaching tests on unsaturated columns. As forest A horizons have larger biogenic Si (BSi) pools than arable lands, we compared the Si release from a forest and a cropland from the same geographical region developed on a Luvisol in Belgium and a Cambisol in Sweden. The A horizons released a quickly dissolving Si fraction in contrast to the B horizons, which did contain no or only little amounts of BSi and released lower Si concentrations. Our experiments show that Si export from forest soils is high because of the presence of a large reservoir of soluble BSi as well as due to the acidity of the soil (pH<4). Leaching at two different water fluxes revealed that export in forest soils was transport controlled while cropland soils were in equilibrium