Armin Skowronek

Future rainfall erosivity derived from large-scale climate models — methods and scenarios for a humid region

The global greenhouse effect is expected not only to increase mean global temperatures, but also to influence characteristics of rainfall. Increased variability of precipitation and a higher amount of erosive rainfall in Middle Europe may also increase soil erosion. In this study the modified Fourniers index is used to derive future rainfall erosivity values by the use of predicted monthly rainfall amounts for elaborating an index in accordance with the universal soil loss equation. The fundamental idea is the significant correlation between this index and the erosivity factor R. Future monthly precipitation data which are required for those calculations were produced by a general circulation model and adjusted to finer scales by expanded downscaling. The results suggest an increase of rainfall erosivity for eight stations in North Rhine-Westphalia (Germany).

Soil chemical properties of a toposequence under primary rain forest in the Itacoatiara vicinity (Amazonas, Brazil)

Abstract Nine soil profiles of a typical toposequence under primary rain forest of the Amazon area were investigated, distinguishing between Geric Ferralsols (Xanthic Kandiudox) in the upper and middle parts of the slope and Geri-Haplic Arenosols (Oxyaquic Quartzipsamments) in the lower ones. Generally, the soils are strongly acid with very high Al contents and show extremely low nutrient contents. In spite of this conformity, significant differences were found referring to the agricultural suitability along the toposequence. The decrease of soil potentials from the top to the lower positions is mainly due to the variation of texture.

Hydrological parameterization of piping in loess-rich soils in the Bergisches Land, Nordrhein-Westfalen, Germany

Pedohydrological properties were investigated on a piped slope in the Bergisches Land in the Rhenish Slate Mountains (Nordrhein-Westfalen, Germany). The study confirmed that genesis and development of pipes decisively depend on hydrological conditions in the soils. Vertical water permeability of saturated samples was very high. This promoted fast seepage. Many macropores produced by earthworms also caused high transport capacity for soil water. Even more efficient were the burrows of moles and mice, enabling immediate infiltration and direct vertical and lateral water movement. On the contrary, the horizontal saturated permeability was low indicating no correlation with piping. Porosity of piped soils was not different to that of other soils of the region without pipes. Hydrologische Parametrisierung von Tunnelerosion in lossreichen Boden des Bergischen Landes, Nordrhein-Westfalen Im Bergischen Land (Rheinisches Schiefergebirge, Nordrhein-Westfalen, Deutschland) wurden bodenhydrologische Eigenschaften auf einem von Tunnelerosion betroffenen Hang untersucht. Die Studie zeigte, dass fur Entstehung und Entwicklung der unterirdischen Rohren die bodenhydrologischen Bedingungen von entscheidender Bedeutung waren. In den Boden war die vertikale gesattigte Wasserleitfahigkeit sehr hoch, was schnelle Wasserversickerung ermoglichte. Auch die zahlreichen, von Regenwurmern geschaffenen Makroporen sorgten fur eine hohe Transportkapazitat fur Bodenwasser. Die Grabgange von Maulwurfen und Mausen waren sogar noch effektiver fur die sofortige Infiltration und eine direkte vertikale sowie horizontale Ableitung des Niederschlagswassers. Demgegenuber war die horizontale gesattigte Wasserleitfahigkeit gering und zeigte keinen Zusammenhang mit der Tunnelerosion. Die Porositat der unterirdisch erodierten Boden unterschied sich nicht von der anderer, nicht betroffener Boden in der Region.

Late Pleistocene loess and their paleosols in the Granada Basin, Southern Spain

Abstract The Granada Basin contains several sites that include Late Pleistocene loess. About seventy samples of fossil soils and sediments in six representative soil sequences were studied using palaeopedological methods. The results form a basis for a regional pedostratigraphy and a high resolution indicator of changing climate during the last interglacial/glacial cycle in the Western Mediterranean. Ten fossil soils of different ages show some similarity to the Middle European loess stratigraphy. It is thus inferred that there was a regular climatic sequence in this region during the Late Pleistocene with sedimentation during dry stadials and soil formation during wetter interstadials even in the sub-humid to semi-arid parts of Southern Spain.

Piping and erodibility of loessic soils in Bergisches Land, Nordrhein-Westfalen

In soils derived from loess on a range land site in the Rhenish Slate Mountains pipes were found at 120—190 cm depth above denser solifluction material. The pipes were 5—30 cm wide and 15—30 cm high. Various soil physical and chemical properties were determined and checked for their suitability as piping indicators. Silt contents reached 808 g kg—1 in the piped soil sections where bulk densities were low to medium in comparison with clay rich and denser horizons beneath. Aggregate stabilities indicated by dispersion features, percolation rates, and dispersion ratios were suitable parameters to indicate piping vulnerability. Organic carbon contents tended to be low in the piped horizons, but there was no relationship between base saturation, ESP or EC values, and piping in the investigated soils. Tunnelerosion und Erodierbarkeit von Losboden im Bergischen Land, Nordrhein-Westfalen In losreichen Boden des Rheinischen Schiefergebirges wurden auf einem Weidestandort Tunnel in 120—190 cm Tiefe oberhalb von dichterem Solifluktionsmaterial gefunden. Die Tunnel waren 5—30 cm breit und 15—30 cm hoch. Es wurden verschiedene physikalische und chemische Bodeneigenschaften bestimmt und auf ihre Eignung als Indikatoren fur Tunnelerosion gepruft. Die Schluffgehalte erreichten 800 g kg—1 in den durchtunnelten Bodenhorizonten, die Lagerungsdichte war hier gering bis mittel hoch, wahrend die darunter liegenden Horizonte tonreicher und dichter waren. Die anhand von Dispergierungsmustern, Perkolationsraten und Dispersionsverhaltnissen ermittelte Aggregatstabilitat erwies sich als geeigneter Parameter zur Kennzeichnung der Anfalligkeit fur Tunnelerosion. Die Gehalte an organischer Substanz lagen in den durchtunnelten Horizonten in der Regel niedrig. Es konnte keine Korrelation zwischen Basensattigung, ESP- oder EC-Wert und Tunnelerosion in den untersuchten Boden festgestellt werden.

Application of gypsum and lime to increase cation adsorption of a Geric Ferralsol in the Brazilian Amazon region

A Brazil-nut plantation 140 km east of Manaus was the site of a 3-month field trial, in which a by-product gypsum and a lime were compared. The soil properties in the plantation, 23 years after slash-and-burn, are not basically different from the remaining primary forest. The comparison is impeded by a distinct spatial variability of the soil nutrient content within the plantation. A linkage between Effective Cation Exchange Capacity (ECEC) and sulfate content of the soil is presumed. Gypsum-application increases the exchangeable Ca considerably, which is not an effect of Al-exchange, but of newly created adsorption sites. The potential of gypsum to increase the ECEC corresponds on a 1:1 basis with the potential for sulfate adsorption in the soil. Mg and nitrate are strongly leached after gypsum application. The applied, extremely fine ground lime has almost no effects below 5—10 cm depth. Ca, Mg and, to a lesser extent, K exhibit a much enhanced adsorption when applied as sulfate instead of chloride. All three cations are preferentially adsorbed in the subsoil, where the ECEC is only half the value of the upper soil. For fertilization concepts of those soils, the subsoil deserves much greater attention. The infiltration pattern of an organic dye gives evidence of a strong influence of bypass water flow through macropores in the soil. Gips- und Kalkanwendung zur Erhohung der Kationenadsorption eines Geric Ferralsol in der brasilianischen Amazonasregion Eine Paranusplantage, 140 km ostlich von Manaus, war Standort fur einen dreimonatigen Feldversuch zum Vergleich eines Nebenprodukt-Gipses und eines Kalkes. Die Bodeneigenschaften der Plantage unterscheiden sich 23 Jahre nach der Brandrodung nicht wesentlich von denen des verbliebenen Primarwalds. Eine hohe raumliche Variabilitat des Nahrstoffgehaltes in den Plantagenboden erschwert den Vergleich. Zwischen der effektiven Kationenaustauschkapazitat (ECEC) und dem Sulfatgehalt der Boden besteht vermutlich ein Zusammenhang. Gipsanwendung erhoht den austauschbaren Ca-Gehalt erheblich, was nicht durch Al-Austausch, sondern durch neu geschaffene Austauschplatze erreicht wird. Das Potential des Gipses, die ECEC zu erhohen, entspricht im Verhaltnis 1:1 dem Sulfatadsorptionspotential des Bodens. Mg und Nitrat werden nach Gipsanwendung stark ausgewaschen. Der verwendete, sehr fein vermahlene Kalk hat fast keine Wirkung unterhalb 5—10 cm Tiefe. Die Adsorption von Ca, Mg und in geringerem Umfang von K wird bei Gabe der Ionen als Sulfat deutlich gegenuber der als Chlorid gesteigert. Alle drei Kationen werden bevorzugt im Unterboden adsorbiert, wo die ECEC nur halb so gros ist wie im Oberboden. Dungungskonzepte fur diese Boden sollten den Unterboden starker berucksichtigen. Das Infiltrationsmuster eines organischen Farbstoffes hebt die grose Bedeutung des Makroporenflusses hervor.

Loess paleosoil-sequences along a climatic gradient in Northern Iran

In Northern Iran, loess is found in diff erent geomorphological settings along a climatic gradient ranging from subhumid to semiarid conditions. Loess-paleosol sequences were investigated in detail in three key sections located on the northern foothills of Alborz mountains (sections at Neka and at Now Deh) and in the loess hills north of Gonbad-e Kavus (section at Agh Band). At the section at Neka, two pedocomplexes consisting of moderately to strongly developed Bwk, Bt or AhBt horizons are intercalated in fi ne textured loess. Luminescence age estimates indicate that the upper paleosol was formed during OIS 5a or 5c, whereas the lower pedocomplex might represent OIS 5e or older interglacial periods. Nine light or dark brown paleosols (CBk, Bwk and Btk horizons) are intercalated in the loess at the section at Now Deh indicating diff erent weathering intensities most likely during interglacial and interstadials periods of the Middle and Upper Pleistocene. Th e upper Bt horizon of Now Deh likely correlates with OIS 5e. Th e lower Bt horizons join to form a strong pedocomplex possibly correlating with OIS 7 or older interglacials. Th e pedocomplexes at Neka and Now Deh indicate polycyclic soil genesis including soil formation, truncation of the upper soil horizons, loess deposition and again soil formation. In the loess hills near Agh Band, 40 m thick homogenous loess covers a brown paleosol (Bw(t)), possibly correlating with the last interglacial soil. Th e loess at Agh Band section has a high percentage of fi ne sand and coarse silt and contains signifi cant amounts of gypsum. Th e loess-paleosol sequences indicate pronounced climate changes from dry and cool to moist and warm conditions with loess deposition and soil formation, respectively. Th ey are excellent terrestrial archives of Quaternary climate and environment change in Northern Iran. [Löss-Paläobodensequenzen entlang eines Klimagradienten in Nordiran]

Zur jungholozänen Oberflächen- und Bodenentwicklung der Siegaue im Hennefer Mäanderbogen

The flood loams in the Sieg valley near Hennef were investigated with geomorphological, sedimentological and pedological methods. They are free of carbonate. Four late Holocene floodplain terraces can be seperated and dated. On the Upper Floodplain Terrace an Auenparabraunerde-Auenbraunerde (Fluvi-Luvic Cambisol) of early Iron Age was found. The pedogenesis on the older Middle Floodplain Terrace lead to a Typische Auenbraunerde (Fluvi-Eutric Cambisol) of Latene Age. The younger part of this terrace is covered by a Braunauenboden (Eutric Fluvisol) of late Middle Ages/modern times. The Lower Floodplain Terrace is the youngest formation, at most 200 years old. It is characterized by an Auengley/Auenregosol (Fluvi-Eutric Gleysol). The Parabraunerde (Luvisol) on the Weichselian Low Terrace is supposed to be of Bronze Age. That anthropogenic flood loams bury traces of a presumably early Holocene soil on the Low Terrace.