Acidity of size-fractionated aerosol particles     

Ludwig  J.  Klemm  O. 《Water, air, and soil pollution》1990,49(1-2):35-50

Water, Air, & Soil Pollution - At three locations in NE-Bavaria (Central Europe), aerosol particles were collected in five size fractions with a cascade impactor. The water soluble part of each...  相似文献   

Changes in properties of soil-derived dissolved organic matter induced by biodegradation   总被引：1，自引：0，他引：1  

Karsten Kalbitz  David Schwesig  Juliane SchmerwitzKlaus Kaiser  Ludwig HaumaierBruno Glaser  Ruth EllerbrockPeter Leinweber 《Soil biology & biochemistry》2003,35(8):1129-1142

Properties of dissolved organic matter (DOM) determine its biodegradation. In turn, biodegradation changes the properties of the remaining DOM, which may be decisive for the formation of stable organic carbon in soil. To gain information on both mechanisms and controlling factors of DOM biodegradation and the properties of biodegraded DOM, we investigated changes in the composition of 13 different DOM samples extracted from maize straw, forest floors, peats, and agricultural soils during a 90-day incubation using UV absorbance, fluorescence emission spectroscopy, FTIR-spectroscopy, ¹H-NMR spectroscopy, pyrolysis-field ionization mass spectroscopy (Py-FIMS), and ¹³C natural abundance before and after incubation. Changes in the DOM properties were related to the extent of biodegradation determined by the release of CO₂. Increasing UV absorption and humification indices deduced from fluorescence emission spectra, and increasing portions of aromatic H indicated relative enrichment of aromatic compounds during biodegradation. This enrichment significantly correlated with the amount of DOC mineralized suggesting that aromatic compounds were relatively stable and slowly mineralized. ¹³C depletion during the incubation of highly degradable DOM solutions indicated an enrichment of lignin-derived aromatic compounds. Py-FI mass spectra indicated increasing contents of phenols and lignin monomers at the expense of lignin dimers and alkylaromatics during incubation. This partial degradation of higher-molecular, lignin-derived DOM compounds was accompanied by relative increases in the proportions of lower-molecular degradation products and microbial metabolites. Carbohydrates, especially when abundant at high initial contents, seem to be the preferred substrate for microorganisms. However, four independent methods suggested also some microbial production of carbohydrates and peptides during DOM degradation. After incubation, the composition of highly degradable DOM samples became similar to relatively stable DOM samples with respect to aromaticity, carbohydrate content, and thermal stability. We conclude that DOM biodegradation seems to result in organic matter properties being a precondition for the formation of stable carbon. These structural changes induced by DOM biodegradation should also result in stronger DOM sorption to the soil matrix additionally affecting DOM stabilization.  相似文献   

The ‘Bavarian Turnip’ — a rediscovered local vegetable variety of <Emphasis Type="Italic">Brassica rapa</Emphasis> L. em. Metzg. var. <Emphasis Type="Italic">rapa</Emphasis>     

Ludwig?ReinerEmail author  Thomas?Gladis  Harald?Amon  Andreas?Emmerling-Skala 《Genetic Resources and Crop Evolution》2005,52(1):111-113

The Bavarian Turnip (Bayerische Rübe, Brassica rapa L. em. Metzg. var. rapa) is a nearly lost crop today. Until 1900, this local variety was commonly grown in Bavaria for human consumption. The special and very distinct characters of this variety in comparison with recent breeds are preferred by the farmers families and assured the persistence and survival of this turnip in situ (on farm). In the region of Dachau and Freising, located north of Munich, only four farms are known, where this old crop is still grown and maintained. Urgent measures have to be taken to safe this cultural relict for future generations.  相似文献   

Carbon and nitrogen mineralization after maize harvest between and within maize rows: a microcosm study using 13C natural abundance     

Bettina John  Bernard Ludwig  Martin Potthoff  Heiner Flessa 《植物养料与土壤学杂志》2004,167(3):270-276

The sequestration of carbon in soil is not completely understood, and quantitative information about the rates of soil organic carbon (SOC) turnover could improve understanding. We analyzed the effects of the uneven distribution of crop residues after harvest of silage maize on C and N losses (CO₂‐C, dissolved organic carbon (DOC) and nitrogen (DON), and NO₃^–) from a Haplic Phaeozem and on the occurrence of priming effects induced by the decomposition of accumulated maize residues. Soil columns were taken from a continuous maize (since 1961) field after harvest i) between maize stalk rows (M_bare), ii) within the maize rows including a standing maize stalk (M_stalk), and iii) from a continuous rye (since 1878) field after tillage (rye stalk and roots were mixed into the Ap horizon). The soil columns were incubated for 230 days at 8 °C with an irrigation rate of 2 mm 10^–2 M CaCl₂ per day. Natural ¹³C abundance was used to distinguish between maize‐derived C (in SOC and maize residues) and older C originating from former C₃ vegetation. The uneven distribution of maize residues resulted in a considerably increased heterotrophic activity within the maize rows as compared with soil between seed rows. Cumulative CO₂ production was 53.1 g CO₂‐C m^–2 for M_stalk and 23.3 g CO₂‐C m^–2 for M_bare. The contribution of maize‐derived C to the total CO₂ emission was 83 % (M_stalk) and 67 % (M_bare). Calculated as difference between CO₂‐C release from M_stalk and M_bare, 19 % of the maize residues (roots and stalk) in M_stalk were mineralized during the incubation period. There was no or only a marginal effect of the accumulation of maize residues in M_stalk on leaching of DOC, DON, and NO₃^–. Total DOC and DON leaching amounted to 2.5 g C m^–2 and 0.16 g N m^–2 for M_stalk and to 2.1 g C m^–2 and 0.12 g N m^–2 for M_bare. The contribution of maize‐derived C to DOC leaching was about 25 % for M_stalk and M_bare. Nitrate leaching amounted to 3.9 g NO₃^–‐N m^–2 for M_stalk and to 3.5 g NO₃^–‐N m^–2 for M_bare. There was no priming effect induced by the decomposition of fresh maize residues with respect to CO₂ or DOC production from indigenous soil organic carbon derived from C₃ vegetation.  相似文献   

Protonenpuffersubstanzen in Böden     

Udo Schwertmann  Peter Süsser  Ludwig Ntscher 《植物养料与土壤学杂志》1987,150(3):174-178

Proton buffer compounds in soils A classification of solid soil buffer substances according to the type of proton accepting sites, viz. carbonate buffer, variable charge buffer, silicate buffer and hydroxide buffer is proposed. The buffer reactions are discussed in some detail and so are formation and transformation processes of buffer. An association of pH-ranges to various buffer compounds is hampered by an insufficient knowledge of the acid strength of the different functional groups.  相似文献   

Phosphate Solubilization by Several Genera of Saprophytic Fungi and Its Influence on Corn and Cowpea Growth     

Marco E. Gudiño Gomezjurado  Lucas M. de Abreu  Leandro M. Marra  Ludwig H. Pfenning 《Journal of plant nutrition》2015,38(5):675-686

The aim of this study was to test the ability of several strains of fungi, which were isolated from the Brazilian Amazon, to solubilize calcium phosphate in vitro and to promote corn and cowpea growth under axenic conditions. Each plant species received six treatments: inoculation with strains with high solubilization index (SI) (Haematonectria ipomoeae CML 3249 and Pochonia chlamydosporia var. catenulate CML 3250) and control treatments: inoculation with strain that does not solubilize phosphate on Pikovskaya agar (PVK) (Acremonium polychromum FSA115), and non-inoculated treatments with high concentration of insoluble phosphate (HPins), high concentration of soluble phosphate (HPs) or low concentration of soluble phosphate (LPs). The fungi strains had SI between 1.07 cm and 2.03 cm including species without previous report in the literature of their capacity to solubilize calcium phosphate. The two phosphate-solubilizing strains promoted greater corn and cowpea root growth than the controls FSA115, HPins and LPs, to a level similar to the HPs control.  相似文献   

Comparison of growth and survival of white shrimp postlarvae (Litopenaeus vannamei) fed dried Artemia biomass versus four commercial feeds and three crustacean meals     

Ludwig C.A. Naegel  Sonia Rodríguez-Astudillo 《Aquaculture International》2004,12(6):573-581

The use of dried Artemia biomass meal as an exclusive feed for postlarval white shrimp (Litopenaeus vannamei) was compared with four commercial feeds and three crustacean meals in a series of trials. Postlarvae (PL1–PL6) were stocked at a density of 1.5–2.5/litres in 16 tanks (100 litres volume) and fed, ad libidum, five times a day, over 23–29 days. Feeding postlarval shrimp with dried Artemia biomass resulted in a significantly larger size than feeding with three of the commercial feeds, and the crustacean meals. There was no significant size difference observed in animals fed with Artemia biomass and the commercial 'Golden Pearls' feed for postlarvae, however the coefficient of variation among the size of the 'Golden Pearls' fed animals was significantly higher. The weight increase of animals fed with Artemia biomass was higher than in animals fed with all the tested feeds. The survival rate was not significantly different in animals fed with Artemia flakes from 'Salt Creek', 'Bio-Marine', 'Golden Pearls' and Artemia biomass, however the survival rate was significantly larger in animals fed with Artemia biomass than in animals fed with the crustacean meals and 'Artemac.' Results suggest that dried Artemia biomass is a well-suited feed for postlarval L. vannamei.  相似文献   

Development of an integrated aquafarming system     

Ludwig C. A. Naegel 《Aquaculture International》1994,2(1):1-9

The integration of aquaculture into agricultural production systems to intensify profitable food production without the usual environmental degradation appears to be a promising option for a large number of small farmers in many developing countries. However, for the adoption of novel production systems, economic considerations are the main driving force. The farmer has to be convinced of the long- and short-term benefits and profits of different farming systems options. The potential farmer-aquaculturist needs site-specific holistic information packages of different production options, as contrasted with packages of technology only, in order to combine traditional knowledge with modern scientific results. These all-embracing data packages for different production systems must take into account the environmental conditions, the availability and price of the stocking material for aquaculture, of farm animals and seeds, seasonal farm and off-farm labour demands, and the socio-economic situation of the farmer and the neighbourhood. The possible production intensities, profits and risks have to be quantified, and the impacts on the environment, the family and society have to be determined. Such information would serve as a guideline for the selection of management options best suited to his/her farming system and would allow a choice of alternatives in case of unforeseen events. The multifaceted obstacles to developing a sustainable integrated aquafarming system are presented for a case in the Philippines.  相似文献   

Structure and function of soil fauna communities in Amazonian anthropogenic and natural ecosystems     

Hubert Hfer  Werner Hanagarth  Marcos Garcia  Christopher Martius  Elizabeth Franklin  Jrg Rmbke  Ludwig Beck 《European Journal of Soil Biology》2001,37(4)

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Black carbon in the zonal steppe soils of Russia     

Andrej Rodionov  Wulf Amelung  Ludwig Haumaier  Inga Urusevskaja  Wolfgang Zech 《植物养料与土壤学杂志》2006,169(3):363-369

Black Mollisols are typically rich in charred organic matter, however, little is known about the zonal distribution of black C (BC) in steppe soils. In this study, we used benzene polycarboxylic acids (BPCA) as specific markers for BC in particle‐size fractions of depth profiles in several zonal soils (Greyzem, Phaeozem, Chernozem, Kastanozem) of the Russian steppe. In addition, liquid‐state ¹³C‐NMR spectra were obtained on the alkaline‐soluble soil organic matter (SOM). The results showed that both the content and depth distribution of BC varies in the different soil types; the concentration of BC in the bulk top soils being closely related to the aromaticity of the SOM (r² = 0.98 for the native topsoils, 0.83 for top‐ and subsurface soils). Especially the Chernozems were rich in aromatic SOM, which partly contained more than 17% BC of total C, most of which being allocated in the mineral fractions. Long‐term arable cropping did not reduce the BC contents of the surface soil, though it did promote the enrichment of BC in the silt fractions. The same shift was detected as soil depth increased. We conclude that BC is not fully inert in these soils, but apparently can be preserved in the silt as decomposition of SOM increased, i.e., it accumulates exactly in that fraction, which has been formerly assigned to contain old, aromatic C.  相似文献