Die Böden des oberen Ouémé-Einzugsgebietes in Benin/Westafrika : Pedologie, Klassifizierung, Nutzung und Degradierung

In dieser Arbeit werden die im oberen Ouémé-Einzugsgebiet Zentralbenins gelegenen Böden charakterisiert und die Degradierung in dem aktuellen low input-Landnutzungssystem untersucht. Darauf aufbauend werden Möglichkeiten einer nachhaltigen Bodennutzung erörtert, um zur langfristigen Sicherung der Ressource Boden beizutragen. Die Böden der flachwelligen Pediplain Zentralbenins sind durch die Schichtung von feinkörnigen und skelettreichen Lockersedimenten über tonreichem Saprolit charakterisiert. Auf den Hängen dominieren Sols ferrugineux tropicaux lessivés bzw. Acrisols, während in den Tälern, den Bas-Fonds, Sols hydromorphes peu humifères bzw. Gleysols entstanden sind. Die natürliche Fruchtbarkeit dieser Böden ist nach der Evaluierung nach LANDON (1984), dem Fertility Capability Classification System (FCC) von SANCHEZ et al. (1982) und der Framework for Land Evaluation (FAO 1976, 1981) allgemein als gering zu bewerten. Als Gründe für die nur mäßige Eignung der Böden für die Pflanzenproduktion sind die niedrige Wasserhaltekapazität, das geringe Bindungsvermögen für Nährstoffe als auch die begrenzte Durchwurzelbarkeit und die starke regenzeitliche Vernässung der Bas-Fonds zu nennen. Auf diesen Böden werden traditionsgemäß vorwiegend Getreide wie Mais oder Sorghum und Yams für den Eigenbedarf ohne den Einsatz von Düngemitteln angebaut. Da die Nutzung des Bodens durch das starke Bevölkerungswachstum in den letzten Jahrzehnten intensiviert und die für die Regeneration des Bodens notwendige Brachezeit verkürzt wurde, wird der Boden auf verschiedene Weise degradiert. Zum einen hat der Bodenabtrag durch Oberflächenwasser zur Verringerung der Substratmächtigkeit auf den Ackerflächen geführt. Die Bodenbearbeitung hat ebenfalls die Verschlechterung der Struktur zur Folge, was neben der geringen Bodenbedeckung durch Nutzpflanzen die Erosion begünstigt. Der wiederholte Abtrag, Buschfeuer, das jährliche Ernten und die Verkürzung der Brachezeiten führen weiterhin zur Verarmung des Bodens an organischer Substanz und Nährelementen, d.h. zur chemischen Degradierung. Auch nimmt der Besatz des Bodens mit Lumbriciden und ihre Aktivität mit zunehmender Nutzungsintensität ab, so dass Ackerflächen ebenfalls einer biologischen Degradierung unterliegen. Um dieser Verschlechterung entgegenzuwirken und die Ressource für zukünftige Generationen zu sichern, ist eine Modifizierung des traditionellen Landnutzungssystems durch verschiedene kulturtechnische und pflanzenbauliche Maßnahmen sowie die Einführung von Düngemitteln erforderlich.The soils in the catchment of the Upper Ouémé in Benin/West Africa - soil genesis, classification, land use and degradation In the work, the soils developed in the catchment of the Upper Ouémé are characterized and their degradation in the current low input land use system is pointed out. Furthermore, possibilities of a sustainable land use are discussed to achieve the conservation of the resource. The soils developed in the undulating pediplain in the centre of Benin are characterized by the layering of fine grained and gravely substrates over saprolite. Sols ferrugineux tropicaux lessivés or Acrisols dominate on the slopes, whereas Sols hydromorphes peu humifères or Gleysols are distributed in the valleys, the bas-fonds. The natural fertility of these soils is low according to LANDON (1984), the Fertility Capability Classification System (FCC) of SANCHEZ et al. (1982) and the Framework for Land Evaluation (FAO 1976, 1981). Some reasons for the low suitability of the soils for plant production are the low field capacity, the low exchange capacity for nutrients, the limited rooting space and the water logging of the bas-fonds during the rainy season. Traditionally, cereals like maize or sorghum and yam are cultivated on the soils without any fertilizer for self-sufficiency. Because of intensified land use due to the increasing population and the shortening of the fallow period which is important for the rehabilitation of the soils, different kind of soil degradation take place. Soil erosion by run off has already led to the reduction of the top surface layer. Furthermore, land use has deteriorated the soil structure due to the low cover of the soil surface and the low density of the crops which favour soil erosion. Soil loss, bush fire, harvesting and the shortening of the fallow period lead to the decrease of organic matter and nutrients which means the chemical deterioration of the soils. The population density of earthworms and their activity are decreased on agricultural used fields which are also biologically deteriorated. To counteract soil degradation and to preserve the resource for further generations, the modification of the traditional land use system by different measures of plant cultivation and the use of fertilizer are necessary

Estimation of medium-term soil redistribution rates in Ibadan, Nigeria, by using the 137 Cs technique

Soil erosion is a widespread and serious problem in Nigeria, West Africa. The 137 Cs technique is an alternative to field plots for generating data on medium-term soil redistri bution. It was tested in 2007 in Ibadan, Nigeria, which means the firs t time in the derived savanna. To analyse the vertical and spatial distribution of this nuclide in the soil, core samples were taken either randomly or along transects in an uncultivated and a cultivated site. The study showed an accumulation of 137 Cs near the soil surface and a slow decr ease with depth in the undisturbed site. The arable land was characterized by an almost uniform 137 Cs distribution within the ploughed layer. The reference inventory of 137 Cs determined on the uncultivated site was 569.3 ± 150.1 Bq m -2 ; the inventory of 137 Cs on the field ranged from 96.9 to 1494.4 Bq m -2 . Comparisons with the reference inventory showed smaller values for the upper slope and higher values for the lower slope of the cultivated site, wh ich indicated soil redistribution. The conversion of the inventories into quantitative data of erosi on and deposition by a proportion model revealed, for example, that about 148.5 t ha -1 yr -1 were eroded from the cropland in furrows leading downslope. The estimated results were comparable to erosion measurements made nearby. Hence, the 137 Cs technique is useful as a method to generate data on soil redistribution a nd therefore a tool for improved natural resource management in Nigeria

Soil sequences atlas. 2

TäistekstThis is the second book in the series of Soil Sequence Atlases. The first volume was published in 2014. Main pedogeographic features are presented in the form of sequences to give a comprehensive picture of soils - their genesis and correlations with the environment in typical landscapes of Central Europe from Estonia furthest north, through Latvia, Lithuania, Poland, Germany, Czechia, Slovakia and Hungary to the southernmost Slovenia. Soils of natural landscapes - loess and sand (continental dunes) - are presented, as well as those of plains of various origin, karst lands, low mountains, and anthropically modified soils. Each chapter presents soil profiles supplemented by landscape information and basic analytical data. Then, genetic interpretations of soil properties related to soil forming agents are given as schematic catenas. When one factor changes while the others are more or less stable, the soil sequence can be recognised. Depending on the dominant soil-forming factor affecting repeated soil patterns, different types can be distinguished. Chapters are arranged roughly in accordance with the main soil-forming process in sequences, and referring to the WRB key (peat formation, vertic and gleyic process, podzolisation, humus accumulation, clay illuviation), with one small exception - the Technosols have been placed at the end of book. The main objective of this book is to present the diversity of relations between soil and landscape, climate, hydrology and human relations, and to present interpretations reflecting the World Reference Base for Soil Resources (2015) classification with comments on the choice of qualifiers. Sixteen Reference Soil Groups are featured, and represented by 67 soil profiles. The secondary objective is pedological education. One of the aims of soil science education is to explain to students the relations between landscape and soil cover. The patterns of soil units within landscapes are to some extent predictable. The collected data is intended as a useful educational tool in teaching soil science, supporting understanding of the reasons for the variability of soil cover, and also as a WRB classification guideline. The Atlas was developed as part of the EU Erasmus+ FACES project (Freely Accessible Central European Soil). Marcin Šwitoniak, Przemyslaw Charzynsk

Cross-linking of chloroplast F,F, -ATPase subunit E to y without effect on activity E and y are parts of the rotor

Cys residues were directed into positions 17, 28, 41 and 85 of a Cysb--+Ser mutant of subunit E of spinach chloroplast F,,F, ATP synthase. Wild-type and engineered E were expressed in Escherichia coli, purified in the presence of urea, refolded and reassembled with spinach chloroplast F, lacking the E subunit [F, (-e)]. Cys-containing c variants were modified with a sulfhydryl-reactive photolabile crosslinker. Photocross-linking o f c to F,(-E) yielded the same SDS gel pattern of cross-link products independent of the presence or absence of MgZ+ . ADP, phosphate and Mg" . ATP. Functional reconstitution of photophosphorylation in F,-depleted thylakoids was observed with F, in which 1' was cross-linked to [Ser6,Cys28]c or (Ser6,Cys41]c but not with wild-type E. In view of the intersubunit rotation of y relative to ( @ ) 3 , which is driven by ATP hydrolysis, 7 and E would seem to act concertedly a~ parts of the 'rotor' relative to the 'stator' (c$)?

Topsoil characterization - recommendations for revision and expansion of the FAO-Draft (1998) with emphasis on humus forms and biological features

International audienceThe characterization of topsoils has recently received enhanced attention, particularly for environmental monitoring. Traditional national and international soil taxonomies hardly consider the topsoil in spite of its importance for soil quality. Consequently, the FAO "Topsoil Characterization for Sustainable Land Management" was developed to be used additionally for describing topsoils and to combine it with the "World Reference Base for Soil Resources" (WRB). In this paper, recommendations for a first step of a revision and expansion of the FAO "Topsoil Characterization" are made. On the one hand, common rules for soil description as used in the FAO "Guidelines for Profile Description" were incorporated in the FAO "Topsoil Characterization". On the other hand, new characteristics for the description of the organic matter and of biological features of the topsoils were introduced. At first, the proposed German systematics of humus forms is presented and correlated with different national systematics, for validation in the international context. Secondly, a correlation of the new German systematics of humus forms with the FAO "Top-soil Characterization for Sustainable Land Management" and other topsoil systematics is made. Thirdly, additional qualifiers are described focussing on the organic layers and the biological features. A coincidence between the characterization of humus forms and topsoils was found which appears to be an appropriate basis for the incorporation of humus forms in the FAO "Topsoil Characterization". Investigations have shown that the topsoils in forests can be described comprehensively by additional qualifiers for the organic layers. Grassland or arable land which usually lack organic layers can be characterized in detail by qualifiers concerning soil biological activity in the A horizon. The methodology was already applied successfully in temperate regions. But there is still a need for further discussion of the revision and for tests in tropical and subtropical zones and poorly drained areas