Die Böden von Wallhecken in Schleswig-Holstein. II. Aufbau und Umsetzung der organischen Bodensubstanz

Soils of Mound Hedges in Schleswig-Holstein. II. Composition and Transformation of Soil Organic Matter Two Cumulic Anthrosols of mound hedges and the fossil A-horizons below the deposits, were investigated by means of wet chemistry and ¹³C-NMR spectroscopy in order to characterize soil organic matter (SOM) and to compare their SOM with natural and recent soils. The bulk humus of the Cumulic Anthrosols contains a high amount of easily soluble polysaccharides. Despite their high bioavailability sugars, starch and mobile fulvic acids are not completely consumed by microorganisms and translocated into the subsoil. The initial phase of podzolization is indicated due to this process and the very low pH-level of the soils. After deposition about 30 % of the soil carbon in the A-horizons is mineralized. Litter compounds are predominantly decomposed, whereas humic compounds are selectively preserved or newly synthesized. The significance of the humic compounds in the soil organic matter increases after deposition. This is why the potential cation exchange capacity of the fossil Ahorizons is similar to this of the recent ones.     

Functional diversity of soil microbial community,rock phosphate dissolution and growth of Acacia seyal as influenced by grass-, litter- and soil-feeding termite nest structure amendments

We tested termite mound materials belonging to different feeding groups: Cubitermes (soil-feeder), Trinervitermes (grass-feeder) and Macrotermes (litter-feeder), as natural microbial inoculum to promote plant growth and increase nutrient supplies from soil organic matter and inorganic amendments (rock phosphate), through their effects on soil microorganisms (functional diversity of soil microflora, arbuscular mycorrhizal fungi, rhizobia, fluorescent pseudomonads, actinomycetes and saprophytic fungi). Experiments were made in a pot experiment with Acacia seyal, a leguminous tree abundant in West Africa, with a sandy soil amended or not with rock phosphate. Results indicated a stimulation of plant growth with Cubitermes and Trinervitermes mound powder (plant height and shoot biomass), similar to what was obtained with rock phosphate alone. Leaf content in N was also increased in the termite treatments (except in Macrotermes soil), whereas mycorrhizal colonization was inhibited as compared to the control. The development of saprophytic fungi was significantly higher in the soils amended with rock phosphate and this effect was hypothesized to be related to the production of large quantities of oxalic acid by fungal populations. The fluorescent pseudomonad populations notably increased in the soils dually amended with mound powders and rock phosphate, and this could be due to the fact that some species of this bacterial group are able to dissolve rock phosphate. The organic and inorganic amendments decreased the soil catabolic evenness in all the mound powder treatments. Among the mound materials tested, Cubitermes mound powder had the most promising effect, especially on SIR response to oxalate. It is concluded that soils amended both with rock phosphate and Cubitermes mound soil could promote the development of microbial communities, which could help to metabolize this compound and consequently enhance plant growth.     

Soil engineering ants increase CO2 and N2O emissions by affecting mound soil physicochemical characteristics from a marsh soil: A laboratory study

As ecosystem engineers, ants can mediate soil processes and functions by producing biogenic structures. In their mounds, ants not only directly produce CO₂ by respiration, but may also indirectly impact soil greenhouse gas emissions by affecting substrate availability and soil physicochemical characteristics. Recent studies focused on overall gas production from ant mounds. However, little is known about mound material respiration and N₂O emissions in ant mounds in wetlands. We measured CO₂ and N₂O emissions from mound soils of three different ant species (Lasius niger Linnaeus, Lasius flavus Fabricius, and Formica candida Smith) and natural marsh soils in a laboratory incubation experiment. On the whole, average soil CO₂ and N₂O emission rates from ant mounds were significantly higher than from the natural marsh soils. Over the 64 days incubation, the cumulative soil CO₂ and N₂O production from ant mounds was, respectively, 1.5–3.0 and 1.9–50.2 times higher than from the natural soils. Soil gas emissions from ant mounds were significantly influenced by the specific ant species, with soil CO₂ and N₂O emissions from L. niger mounds being higher than those from F. candida or L. flavus mound soils. Cumulative CO₂ and N₂O emissions from ant mound soils were positively correlated with soil clay, total carbon, dissolved organic carbon, total nitrogen and NH₄⁺ content. Our laboratory results indicated that mound soil is an important source of CO₂ and N₂O emission from ant mounds in marshes, making mounds potential “hot spots” for CO₂ and N₂O emissions. Ants may increase the spatial heterogeneity of soil gas emissions by changing mound soil physicochemical properties, especially carbon and nutrition content, and soil texture. Contributions from ant mound materials should be considered when describing soil C and N cycles and their driving factors in wetland ecosystems.     

Peat soils: Genesis and classification

This paper considers three topical problems—the definition of peat soils as natural-historical formations and the estimation of their profile thickness, the analysis of the genesis of organic soils, and the principles of the classification of peat soils. Based on the experimental data of long-term studies, it was concluded that peat soils may include the whole peat layer and the upper horizons of the surface mineral soil. The organic and mineral parts of the natural structures were found to be a genetically homogeneous soil profile, which has the same history of development. The upper layer of the peat soils should be considered as the horizon reflecting the contemporary stage of the soil formation. A hierarchy of peat soils is analyzed for developing their classification.     

Colluvisols under cultivation in Schleswig-Holstein. 1. Genesis,definition and geo-ecological significance

In Schleswig-Holstein, F.R.G., two typical soil associations from loamy boulder marl and loamy pleistocene sands were mapped and ecologically characterized in order to show the necessity of an adequate classification of Colluvic Cumulic Anthrosols (Colluvisols). More than 50% of the original soils have been altered by erosion. The depth of the colluvic wM horizon ranges between 10 cm and more than 100 cm. The amounts of soil organic matter and plant available nutrients are much higher in the Colluvisols than in the haplic soils. Soil classification does not deal with all these aspects with regard to mapping of colluvic soils. In the German soil classification adequate and ecologically significant definitions and instructions of the nomenclature of colluvic soils are not available. Therefore, a proposal is presented to classify colluvic soils. In addition the threshold value of 0.6% soil organic matter in sandy parent material is too low in order to distinguish a Bv from a M horizon; 1.0% would be a more acceptable value. It would be necessary to investigate yield on erodic, non-erodic and colluvic soils in order to determine the effect of erosion and accumulation on crop yield.     

3-D soil macropore networks derived from X-ray tomography in an alpine meadow disturbed by plateau pikas in the Qinghai Lake watershed,north-eastern Qinghai-Tibetan Plateau

Purpose

The plateau pika (Ochotona curzoniae) is one of the main native soil faunas on the Qinghai-Tibet Plateau and plays a key role in the terrestrial ecosystem there. However, few studies have analysed the macroporosity of soils disturbed by plateau pikas in alpine meadows. The objective of this study was to examine the soil macropores in different parts of an alpine meadow in the Qinghai Lake watershed, namely, an original grassland, a new mound, an old mound, and a bald patch.

Materials and methods

In this investigation, soil cores were obtained from four different parts of an alpine meadow, namely, from under an original grassland, a new mound, an old mound, and a bald patch. A total of twelve soil cores (0–50 cm deep) were excavated, which included three replicates of each treatment. The soil architecture of each soil core was explored using X-ray computed tomography.

Results and discussion

The macroporosity decreased and then increased from the original grassland to the new mound, old mound, and bald patch. The soil macropores were most abundant up to a depth of 400 mm in the original grassland and up to a depth of 250 mm in the old mound and bald patch soils.

Conclusions

The macropores in the original grassland were attributed to well-developed root systems. The smaller and less continuous macropores in the new mound, old mound, and bald patch soils were mainly disturbed by plateau pikas. It was expected that water would move preferentially through the macropores in the original grassland, while surface flow would more readily occur in the new mound, old mound, and bald patch soils, thereby leading to soil erosion.

     

Ecology,classification and soil pattern of colluvial soils of the bornhoeved lake district (North-Germany)

Water erosion causes the accumulation of soil material, especially at the bottom slope and in landscape depressions. According to FAO-UNESCO (1990) colluvial soils can be classified as Cumuli-Aric Anthrosols if the minimum thickness of the altered topsoil is 5 dm or more. These soils are characterized by addition of small amounts of soil material that has been incorporated into the underlying material by tillage and/or turbation. As a result of geological factors and land-use intensities, Cumuli-Aric Anthrosols differ markedly in their ecological properties. In the study area ‘Bornhoeved Lake District (Schleswig-Holstein, North-Germany)’ soil patterns have been investigated showing the interdependence of soil landscapes and their soil units by water erosion and accumulation. Examples of various colluvial soils in catenary sequences in the study area are presented. Colluvial soils in the study area are characterized by a layer thickness between 5 and 14 dm and show significantly higher quantities of organic matter, nitrogen and plant-available water in comparison with eroded soils.     

Effects of Ant Mounds on the Plant and Soil Microbial Community in an Alpine Meadow of Qinghai–Tibet Plateau

Ants are important soil engineers, affecting the structure and function of ecosystems. To address the impacts of ants (Camponotus herculeanus ) on the properties of an alpine meadow ecosystem of Qinghai–Tibet Plateau, we investigated the effects of ant mounds on plant biomass, soil physicochemical properties, microbial diversity, and functions. We found that the total biomass of plant community was significantly greater in ant mound periphery. Plant species richness in ant mounds was reduced compared with that of control plots without ant mounds. Significant changes in physicochemical properties of soil were also observed. Soil organic matter, total nitrogen, available phosphorous, total potassium, and available potassium increased in ant mound soil due to the excavation activities by ants as well as the accumulation of organic matter and other nutrients during mound construction. For example, roots/soil contents (g/g) and soil moisture in ant mound soils were lower than those in controls. Microbial community composition and microbial biomass were clearly changed in ant mound soils. BIOLOG analysis further indicated that the functional diversity of the microbial community of ant mound soil increased and differed from that of controls. This study indicates that ant‐induced modification of soil properties indirectly influences plant biomass and species composition, and ant mounds have different microbial communities from those of control soil. Copyright © 2016 John Wiley & Sons, Ltd.     

Physicochemical and morphological properties of termite (Macrotermes bellicosus) mounds and surrounding pedons on a toposequence of an inland valley in the southern Guinea savanna zone of Nigeria

Abstract

Termites play a significant role in soil-forming processes of the tropics. The influence of termites on pedogenesis as affected by the toposequence, however, has rarely been explored. We investigated the soil physicochemical and morphological characteristics of epigeal mounds constructed by Macrotermes bellicosus (Smethman) compared with those of surrounding pedons along a toposequence (bottom, fringe and upland sites) of an inland valley in central Nigeria. The physicochemical and morphological properties of the mound soils varied according to structural units but were generally different from those of the adjacent pedons. The differences included finer texture, higher electrical conductivity, total N, exchangeable bases (Ca, Mg and K) and effective cation exchange capacity and lower C/N ratio and exchange acidity in the mound than the pedon at each toposequence position. This tendency to modify the soil properties was more prominent in the nest body where the termites actually live, that is, in the hives, royal cell and base-plate, than in the soils below the nest and the other mound parts, that is, the external wall, internal wall and pillars. We found this trend to a greater or lesser degree at all toposequence positions. Our findings suggest that: (1) M.?bellicosus can manipulate the mound soils according to functional applications of structure units or environmental requirements for its livelihood, regardless of local soils; (2) M.?bellicosus makes ecological patches (hot spots) at all toposequence positions in the same measure; (3) the influence of M.?bellicosus on the pedogenesis is reduced in the lowlands compared with the uplands because the number and volume of the mounds were substantially lower in the bottom and fringe sites compared with the upland site.     

Plaggen Soils: landscape history,properties, and classification

Plaggen soils were produced by farmers in the sandy lowlands of Denmark, NW Germany, Belgium, and the Netherlands by long‐term application of plaggen manure. The present paper summarizes the genesis, the properties, and the landscape impact of plaggen soils. The objectives and methods of plaggen management are outlined. Evidence for the plaggen management can be traced back to the late Bronze Age. It has continued until the last century. Numerous references indicate the geographical expansion of plaggen management over Europe. The various conditions of plaggen soil formation are reflected by their basic physical and chemical properties. Recent investigations of soil organic matter composition in sandy plaggen horizons revealed large proportions of lipids and fatty acids and some similarity with organic matter in Podzol B horizons. Finally, the classification of plaggen soils is discussed. In the World Reference Base of Soil Resources (ISSS/ISRIC/FAO, 1998), most of them are classified as a separate subunit: within the reference soil group of Anthrosols, they differ from other artificially transformed soils, and are classified as Plaggic Anthrosols.     

Ertragssimulation mit “Ceres Wheat” an Grundwasserböden gemäßigter Klimazonen. Teil 2: Verifizierung des geänderten Modelles “Ceres Wheat”

Calibration of the simulation model “Ceres Wheat” under conditions of soils with shallow watertable and temperate climate. Part 2: Verification of the modified model “Ceres Wheat” The Ceres Wheat yield model has been adopted to soils under wet conditions and to humide climate. The basic assumptions of the modified model have been checked. The simulated results of the soil water balance, the plant development and the nitrate losses by drain discharge give fairly well agreements to field data from a Calcaric Fluvisol (Speicherkoog, Schleswig-Holstein). The modification improves the model and leads to the opportunity to simulate special aspects in agronomical and ecological advices.     

Microbiological characterization of the structures built by earthworms and ants in an agricultural field

The genesis and architecture of the structures built by ants and earthworms differ markedly, suggesting that—in addition to having different physical and chemical properties—the resident microbial community should also have unique properties. We characterized the inorganic N, biomass C, C mineralization rate, and functional diversity of the microbial communities of earthworm casts, earthworm burrow soil, ant mounds, and bulk soil from an agricultural field. Mound soil was most enriched in inorganic N and had the lowest pH, moisture content, and C mineralization rate. Functional diversity was evaluated by determining the ability of microorganisms to grow on 31 substrates using Biolog^®EcoPlates in combination with a most probable number (MPN) approach. Casts had MPNs that were one to two orders of magnitude higher than burrow, mound and bulk soil for most substrates. Casts also had the highest MPNs for particular substrate guilds relative to bulk soil, followed by mound and burrow soil. Indices of substrate diversity and evenness were highest for casts, followed by burrow, mound, and bulk soil. Differences in the type of habitat provided by the structures built by ants and earthworms result in the differential distribution of nutrients, microbial activity, and metabolic diversity of soils within an agricultural field that affect soil fertility and quality.     

Impact of a soil feeding termite,<Emphasis Type="Italic"> Cubitermes niokoloensis</Emphasis>, on the symbiotic microflora associated with a fallow leguminous plant<Emphasis Type="Italic"> Crotalaria ochroleuca</Emphasis>

The influence of a soil-feeding termite nest (Cubitermes nikoloensis) on the development of a symbiotic microflora (rhizobia, arbuscular mycorrhizas) was tested in a pot experiment with a tropical legume (Crotalaria ochroleuca). Our results confirmed the role of soil-feeding termite nests as sites of high nutrient concentration, as a significantly higher content of available P and mineral-N was found in the mound wall. Arbuscular mycorrhizal spores increased in the soil near the termite mound. The mound soil itself almost totally depressed mycorrhizal establishment. The positive effect of the soils close to the mound was also evidenced by the number of nodules per root system as well as the nodule biomass per legume plant grown on this medium. Better growth of Crotalaria seedlings was observed in the soils from the mound wall; the shoot biomass increased by a factor of 9 and the root biomass by a factor of 6 as compared to the control soil (10 m away from the mound). Plant growth on soils from the immediate vicinity of the mound showed intermediate results but a higher N content per biomass unit. This probably reflected the association with arbuscular mycorrhiza and rhizobia. This work evidenced the linkage of plant nutrition to nutrient availability in mound material and the indirect mediating effect of the symbiotic microflora.     

Verification of the <Emphasis Type="Italic">Classification and Diagnostic system of Russian soils</Emphasis> (2004) on the materials of a collection of soil monoliths from the V.V. Dokuchaev Central Soil Museum

The first in the world collection of soil monoliths from the Dokuchaev Central Soil Museum (St. Petersburg) was examined in order to test and verify the new substantive-genetic classification system of Russian soils. This work made it possible to introduce a number of refinements in the second edition of the Russian soil classification system (2004). These refinements included the addition of new diagnostic horizons and features and the specification of their definitions. The analysis of the museum collection of soils has definite advantages, as it allows one to work with soils from different geographic regions simultaneously, to consider morphological features of soils under standard conditions, to use analytical soil data, and to analyze different names (i.e., interpretations of the genesis) given to the same soils. At the same time, a critical analysis of the collection creates necessary prerequisites for a comparative analysis of soils from different regions of Russia with the national reference soil base, which is important in order to reveal the real pedogenetic diversity and improve the information base on soil resources in Russia.     

Land use history and historical soil erosion at Albersdorf (northern Germany) — Ceased agricultural land use after the pre-historical period

The Holocene landscape history and historical soil erosion were reconstructed at Albersdorf (Schleswig-Holstein, Germany) from soils and colluvial layers. In contrast to many landscapes in central Europe, agricultural land use and soil erosion were more frequent during pre-historical times, whereas it has almost ceased after the advent of history. Pre-historical soil erosion rates from about 0.1 to 6.9 t ha^− 1 a^− 1 were reconstructed with no significant differences between the prehistoric cultural phases. The study of buried soils within the soil/soil-sediment-sequences provided evidence for an acceleration of soil formation processes probably as a consequence of excessive prehistoric woodland pasture on poor sandy soils.     

The problem of soil interpretation according to the WRB 2014 classification system in the context of anthropogenic transformations

Evaluation of soil transformations and degradation is important not only for agriculture, but also for fundamental research on identification of new features for classification. In 1999, new Lithuanian soil classification (LTDK-99) was developed by adopting the diagnostic principles of WRB 1998. Together with new knowledge, it highlighted some relevant soil research and classification problems. Not only new terms but also diagnostic features of several newly distinguished first-level soils groups are being discussed, especially for the identification of cambisols, planosols, arenosols, and regosols. Additionally, a group of stagnosols is suggested for inclusion into this classification. The presence of glaciogenic secondary clay minerals in Lithuanian cambisols does not imply unambiguous brownification involvement, neither any study shows cambisols having specific to brownification iron minerals. The intensively occurring lesive in these soils questions correctness of identification of cambisols additionally aggravated by strong and deep anthropogenization of the soil profiles within the territorial range. Complex glaciogenesis makes it difficult to identify Lithuanian planosols. WRB 2014 (update 2015) identifies planosols according to the pedogenesis in old, strongly weathered binomial deposits using examples mostly from South American, South and East African plateaus of the subtropical zone. The same classification assigns planosols identified in Lithuania to stagnosols, that is, to the soils characterized by binomial genesis and stagnification. The diagnostic features of arenosols and regosols are similar in both groups and are related to primitive pedogenesis. Difficulties in distinguishing between the two groups in Lithuania are strengthened by the intensive cultivation of the ecosystems in their territorial range. The existing problems in Lithuanian soil diagnostics underline the questions of soil classification in general, especially regarding the evolution tendencies in soil classification. The article draws attention to the soil diagnostic aspects like distribution and genesis of clay particles, genesis of territory, and anthropogenic transformation for the improvement of soil identification.     

Dynamics of soil properties and organic carbon pool in topsoil of zokor-made mounds at an alpine site of the Qinghai–Tibetan Plateau

The population of burrowing plateau zokors (Myospalax baileyi) was markedly increased in the Qinghai–Tibetan Plateau. The objective of this study was to investigate the effects of zokor foraging and mound-making disturbance on topsoil properties and organic C pools at an alpine site of the Qinghai–Tibetan Plateau. Surface (0–15 cm) soil samples were collected from mounds with different ages (3 months and 3, 6, and 15 years) and from undisturbed grassland. Above- and below-ground plant biomasses were depleted by zokors in newly created mounds (3 months). Plant cover and root biomass gradually recovered thereafter, but were still lower in the 15-year-old mounds than in the undisturbed soils. Organic C contents of coarse (>2 mm), soil (<2 mm), particulate (2–0.05 mm) fractions, and microbial biomass, organic C mineralization, β-glucosidase activity, urease activity, alkaline phosphatase activity, acid phosphatase activity, and soil aggregation were significantly lower in the 3, 6, and 15-year-old mound soils than in the undisturbed soils or newly created mound soils. Fifteen years after mound creation, the soil had only 12% of root biomass, 35% of coarse organic C, 83% of particulate organic C, 58% of microbial biomass C, 57% of 30-day respired C, and 45% of water-stable aggregate mean weight diameter, compared to values of the undisturbed soils. Our results suggested that foraging and mound-making by zokors have negative impacts on properties and organic matter content of the topsoil.     

THE MORPHOLOGICAL, PHYSICAL AND CHEMICAL PROPERTIES OF TWO MOUNDS OF MACROTERMES BELLICOSUS (SMEATHMAN) COMPARED WITH SURROUNDING SOILS IN SIERRA LEONE

The mounds are situated in the Makeni Area, Northern Province, Sierra Leone. Seventy five percent of this area consists of clayey upland soils that belong to the Makeni series (Typic Paleudult), which contain about 80 per cent of gravel-sized hardened plinthite glaebules. The upland is dissected by numerous streams along which gravel-free fine-loamy terrace soils occur that belong to the Masuba series (‘Plin thic’Udoxic Dystropept) occupying about 15 per cent of the area. Mound 1 is a young inhabited mound on a Masuba soil, whilst mound II is an old abandoned mound on a Makeni soil. A trench was dug from the centre of the mounds into the surrounding soils. Profiles were described and samples were analyzed for organic carbon, CEC, exchangeable Ca, Mg, K, Na, and pH, and for particle size analysis with 5 sand fractions. The material used to build the mounds is derived from the subsoil (between 30 and 100 cm depth). Termite channels extended laterally for at least 10 m for mound I, but could not be traced so clearly for mound II. Mound I and the nest of mound II contain a higher percentage of particles less than 250 μm than the surrounding subsoil. Material over 2 mm is not carried by termites. Both mounds show a higher base saturation and higher values of exchangeable Ca, Mg and K, compared to the surrounding subsoil. Increased CEC and pH are noted in mound I and the nest part of mound II, the latter also showing increased values of exchangeable Na. Organic carbon values are equal to those of the surrounding subsoil. Accumulation of mineral elements from organic matter collected as food, including small contributions from the fungus combs and termite bodies, is primarily responsible for the observed differences. In view of the water analyses no contribution is expected from the fluctuating groundwater table.     

Effect of different termite feeding groups on P sorption and P availability in African and South American savannas

Nest structures of six termite species, four with epigeous (above-ground) and two with subterranean nests were analysed to find out how their building and feeding habits could be related to their nests phosphorus status compared with control soils. Termite nest structure was found to affect significantly the P status in savanna soils: mounds of the African Trinervitermes geminatus and the South American Nasutitermes ephratae (both grass-feeders) displayed a greater amount of available P, especially in the inner part of the nest, than the surrounding soil. The abundant quantities of dead grass material stored in the mound can explain the available soil P increase. A similar increase in P availability was also found for the soil-feeder Cubitermes severus. In mounds of Macrotermes bellicosus, on the other hand, there was a drastic increase in P sorption (and a corresponding decrease in available P) compared to adjacent soils, which was attributed to the building strategy of this species. M. bellicosus selected clay from subsoil to build its nest structure. The data obtained for the subterranean species Ancistrotermes cavithorax and Microtermes toumodiensis indicated also that there is an increase in P sorption in mounds when compared with associated topsoils. Consequently, the nest structures of only certain termite species should be considered, and utilised, as a soil amendment in place of fertilisers. This impact on the P cycle in savannas seems to be related to the termite feeding status and to the type of material utilised in nest building. This should be taken into account before using termite nest material in soil fertility status improvement.