bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial and temporal variations of the january circumpolar vortex over the northern hemisphere
Authors: Davis Robert E. , Benkovic Stephanie R.
Published: February 2007

Temporal and spatial variations of the Northern Hemisphere's circumpolar vortex are analysed for each January from 1947 to 1990. Our data set is developed by digitizing the 546‐dam isoheight from 50‐kPa charts and recording the latitude of this contour at each 10° meridian. Principal components analysis is applied to the resulting 699‐day by 36‐variable matrix to examine the temporal and spatial evolution of the circumpolar vortex.

The first principal component is comparable to the Pacific‐North America (PNA) teleconnection pattern. Over the 44 Januarys analysed, the frequency of the positive phase of the PNA pattern has increased. Principal component 2 is similar to the Eurasian pattern and varies between axially asymmetric zonal flow and a three‐wave pattern centred over the pole. The asymmetric pattern, which is characterized by higher heights over western Europe and Scandinavia, has increased in frequency over the study period. With the third principal component, which is similar to the East Atlantic teleconnection pattern, the strength of the Icelandic Low varies markedly. Time series of scores on the third component indicate that 50‐kPa heights over the North Atlantic are lower over the past 20 years. The fourth principal component is related to vortex area. The northern vortex has occupied a more expanded position since the mid‐1960s. These first four principal components explain half of the total variance in the data.

In toto, these results indicate that the January circumpolar vortex has expanded over the past two decades. Most of the expansion has occurred in the vicinity of the Aleutian Low and has produced increased meridional flow throughout much of the Western Hemisphere. This circulation change could account for the observed increased occurrence of warm air masses in winter over eastern Alaska and western Canada, increased cyclone occurrence in the north‐western Atlantic, and both the increased frequency of Arctic outbreaks and declining temperatures in the south‐eastern USA. The overall vortex expansion is contrary to general circulation model forecasts that predict a decrease in the meridional temperature gradient of the Northern Hemisphere as trace‐gas concentrations increase.
Creation of homogeneous composite climatological reference series
Authors: Peterson Thomas C. , Easterling David R.
Published: February 2007

Most techniques used to adjust climatological time series for inhomogeneities require a homogeneous reference series for comparison with each time series being evaluated. However, creating homogeneous reference series from data with unknown inhomogeneities presents many obstacles. Although a truly homogeneous reference series may, in fact, not be obtainable, in this article we present a method that has proven successful at minimizing inhomogeneities in the creation of reference climatological time series. The method utilizes a multistep process based on non‐parametric statistics and an alternative way of relating two time series through correlation analysis. This alternative uses the year‐to‐year change in the variable under consideration (e.g. temperature) as the basis for correlation.
An automated procedure for the identification of synoptic types applied to the new zealand region
Authors: Kidson John W.
Published: February 2007

Cluster analysis has been applied to 9 years of daily 1000 hPa analyses for 1980–1988 over the New Zealand region. The resulting 13 synoptic groupings are characterized mainly by high‐pressure cells and pressure gradients reflecting the predominant wind directions. Low‐pressure centres are not well represented, presumably because of their smaller horizontal scale and lower frequency of occurrence.

Seasonal variations in cluster frequency over this period typically differ by a factor of two. The most persistent patterns are associated with highs to the south of New Zealand, whereas the transitions between clusters show the familiar sequence of eastward‐propagating high‐pressure cells interspersed with troughs.

It is anticipated that these synoptic classifications will prove helpful in interpreting inter‐annual climate fluctuations, in validating the performance of climate models for the New Zealand region and in providing improved guidance to forecasters. Their application to the analysis of daily and monthly variations in climatic elements is described in a companion paper.
Climate change, potential evapotranspiration and moisture availability in the mediterranean basin
Authors: Palutikof J. P. , Goodess C. M. , Guo X.
Published: February 2007

Simple methods for estimating potential evapotranspiration, requiring only temperature and day length data, are compared by reference to the results from the Penman method. A modification of the Blaney and Criddle method, in which the c parameter is calculated from seasonal regression equations with the mean monthly temperature as the independent variable, is proposed and tested. It is found to work sufficiently well in the area of interest, the Mediterranean Basin. For a network of 248 Mediterranean temperature stations, present‐day seasonal mean potential evapotranspiration is estimated by this method. Using the results from four equilibrium‐mode general circulation models, seasonal mean scenarios of potential evapotranspiration per 1°C rise in global mean temperature caused by the enhanced greenhouse effect are presented. Comparison of scenarios of the change in potential evapotranspiration and scenarios of the change in precipitation indicates an unfavourable shift in moisture availability due to the enhanced greenhouse effect, throughout the Mediterranean region.
Impact of ENSO episodes on the autumn rainfall patterns near S˜o Paulo, Brazil
Authors: de M. B. S. Xavier Teresinha , Dias Maria A. F. Silva , Xavier Airton F. S.
Published: February 2007

The relative rainfall intensity for autumn near the city of São Paulo, Brazil, is analysed using 89 rain‐gauge stations. Identifying monthly accumulated precipitation extremes in May for the 1935–1991 period is the main aim of this work. The results show a marked influence of strong El Niño events on the spatial organization of rainfall in the neighbourhood of São Paulo. The pattern of relative rainfall intensity shows decreasing values from the north‐west and north of the area to the south‐east and south, respectively, in strong El Niño years (mainly in May) in contrast to other patterns in other years. This result may be due to low‐level wind‐regime anomalies interacting with the topography of the region.
Greenhouse warming and threshold temperature events in Victoria, Australia
Authors: Hennessy K. J. , Pittock A. B.
Published: February 2007

Small changes in the mean climate can produce relatively large changes in the frequency of extreme events. Two experiments were performed: (i) a sensitivity study where observed temperatures at climate stations were increased by either 1°, 2° or 3°C, and (ii) a scenario study for the year 2030 where temperatures were increased according to warming scenarios which vary spatially and seasonally.

The sensitivity study shows that at some sites, up to four more summer days over 35°C occur for a 1°C warming and the frequency is more than doubled for a 3°C warming. The frequency of subzero winter days is halved for a 1°C warming. At selected sites, the current probability of a run of at least five summer days over 35°C is doubled for a 1°C warming and increases by a factor of five for a 3°C warming. Where the current probability of a run of at least five winter days below 0°C is less than 50 per cent, a 1°C warming reduces the probability by a factor of about three. A 10 per cent change in temperature variance is unlikely to significantly alter these results.

A low warming scenario for 2030 gives at least 25 per cent more days over 35°C in summer and spring, and at least 25 per cent fewer winter days below 0°C. A high warming scenario produces 50–100 per cent more extremely hot summer and spring days and 50–100 per cent fewer extremely cold winter days. Larger percentae changes occur in regions where absolute changes are smaller.

The high scenario also gives a 20 per cent increase in the probability of a run of five summer days over 35°C in the northern half of the State, and the risk of a run of five winter days below 0°C is reduced by less than 20 per cent in the western and coastal areas and by 25–40 per cent in the north‐east highlands. Although a reduction in frost frequency may benefit agriculture, more extremely hot temperatures may increase bushfire potential, human mortality, and heat stress to livestock and crops.
Luni‐solar and solar cycle signals in lake Saki varves and further experiments
Authors: Currie Robert G.
Published: February 2007

Spectrum analysis of over 4000 years of Lake Saki varve data in 200‐year swaths yields evidence for two peaks with periods 18·5±1·5 years (18 out of 21 series) and 10·7±0·8 years (in 15 series). Statistical tests show that the long‐period peak is statistically significant at a 98 per cent confidence level. The peaks are identified as the luni‐solar 18·6‐year, Mn, and the 10–11‐year solar cycle, Sc, signals in climate. Amplitudes of both terms are highly non‐stationary with respect to time, and the phase of Mn wavetrains is also highly non‐stationary, often displaying abrupt changes of 180°. On average the two terms account for 20 per cent of total variance in the raw Saki series, the Nyquist frequency of which is 0·5 cpy. This of course is highly unrealistic—and when the power in the raw Saki data from 0·125 cpy (period of 8 years) to the Nyquist is filtered out prior to analysis, and the variance contribution of the signals to filtered data compared over a common frequency interval (periods 30 to 8 years), their variance contribution increases dramatically to 78 per cent. Such experiments have been carried out for thousands of climate records with similar results, and examples from both published and unpublished data are given herein. Thus, the spectrum of climate from 30 to 8 years has turned out to be strongly ‘signal‐like’ rather than ‘noise‐like’ as radically assumed by statisticians/mathematicians over the past 70 years.
Seasonal and diurnal patterns of dry‐ and wet‐bulb temperatures over Argentina
Authors: Rusticucci Matilde , Vargas Walter
Published: February 2007

The diurnal and seasonal patterns of the dry and wet bulb temperatures over Argentina are studied. The wet bulb temperature frequency distributions have negative skewness over all the country. The higher values are in the lower latitude stations, which are under a subtropical regime. The dry bulb temperature frequency distributions change their skewness from north (negative values) to south, and the highest positive value occurs at the most southerly station, which is under a middle latitude regime.

Three stations in the Buenos Aires area are analysed to study the effects of the river and the city on temperature. The effects of the city and the river on the dry bulb temperature and the wet bulb temperature depend on the wind direction and the time of day. The effect of the river also depends on the month. These effects are also present in the anomalies. If it is necessary to represent extreme climatic or synoptic conditions over a region then the city stations are more appropriate than coastal ones.
Construction of a 1961–1990 European climatology for climate change modelling and impact applications
Authors: Hulme M. , Conway D. , Jones P. D. , Jiang T. , Barrow E. M. , Turney C.
Published: February 2007

A 1961–1990 mean monthly climatology for a ‘greater European’ region extending from 32°W to 66°E and from 25° to 81°N has been constructed at a resolution of 0.5°latitude by 0.5° longitude for a suite of nine surface climate variables: minimum, maximum, and mean air temperature; precipitation totals; sunshine hours; vapour pressure; wind speed; and (ground) frost day and rain day ( > 0.1 mm) frequencies. This climatology has been constructed from observed station data distributed across the region. Station frequencies range from 936 (wind speed) to 3078 (precipitation). Over 95 per cent of these data are based on observations between 1961 and 1990 and over 90 per cent were supplied by individual national meteorological agencies (NMAs) on specific request. For four variables, some standardization of the data had to be performed because different countries supplied data under different definitions. Thus cloud cover had to be converted to sunshine hours, relative humidity to vapour pressure, air frost days to ground frost days and rain days > 1 mm to rain days > 0.1 mm.

The interpolation of the station data to the grid used elevation as one of the predictor variables and thus enabled three climate surfaces to be produced for each variable, reflecting the minimum, mean, and maximum elevation within each 0.5° by 0.5° cell. Subsets of stations were used for the interpolation of each variable, the selection being based on optimizing the spatial distribution, source priority and length of record. The accuracy of the various interpolations was assessed using validation sets of independent station data (i.e. those not used in the interpolation). Estimated mean absolute errors (MAE) ranged from under 4 per cent for vapour pressure to about 10 per cent for precipitation and up to 20 per cent for wind speed. The accuracy of the interpolated surfaces for minimum and maximum temperature was between 0.5°C and 0.8°C.

We believe these results constitute the first climatology that has been constructed for this extensive European region at such a fine spatial resolution (0.5° by 0.5°) from relatively dense station networks, for three different elevation surfaces and for a wide range of surface climate variables, all expressed with respect to a standard 30‐year period. The climatology is already being used by researchers for applications in the areas of ecosystem modelling, climate change impact assessment and climate model validation, and is available from the authors.
Murine model of prosthesis failure for the long‐term study of aseptic loosening
Authors: Yang Shang‐You , Yu Haiying , Gong Weiming , Wu Bin , Mayton Lois , Costello Richard , Wooley Paul H.
Published: February 2007

We examined a novel mouse model of wear debris‐induced prosthesis instability and osteolysis, and its application for the evaluation of therapy. A stainless steel or titanium‐alloy pin was implanted into the proximal tibia to form a contiguous surface with the articular cartilage. In some mice, titanium particles were injected into the tibial canal during the surgery, followed by monthly intraarticular injection. MicroCT scans revealed that the implants without particle challenge were stable without bone mineral density changes for 6 months. Histological analysis showed new bone formation around the implant at 6 weeks postsurgery. Periprosthetic soft tissue with inflammatory cells was a ubiquitous finding at the interface between the implant and surrounding bone in samples exposed to titanium particles, and expression of IL‐1β, TNFα, and CD68 was common in these joints. Pullout tests indicated that an average 5N load was required to pull out stable implants from surrounding bone. However, particle stimulation dramatically reduced the pullout force to less than 0.4 N. The feasibility of in vivo gene transfer on this model was confirmed by X‐gal staining of synovial membrane and periprosthetic tissue after injection of AAV‐LacZ in the prosthetic joint. This murine model of weight‐bearing knee prosthesis provides an economical, reproducible, and easily obtained means to study joint arthroplasty failure. The ability to evaluate the biomechanical properties of the prosthetic joint, in addition to histological and biochemical examination, results in a useful model to investigate many of the properties of prosthetic joint components during the response to debris‐associated osteolysis. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:603–611, 2007
Automatische Registrierung der Feuchtdichte und der Wassergehaltsänderung eines Bodens durch Messung der Absorption von Gammastrahlen (Geländemessung)
Authors: Lorch S.
Published: February 2007

Determination of the moisture density and the water content variation of a soil by measuring the absorption of gamma rays

A method is described with which above all the density and its changing (water content) can be measured automatically. A collimated gamma ray (137‐Cs) is measured according to the absorption principle.

Two tubes are inserted into the soil as parallel as possible about 50 cm apart. In the one tube a gamma ray source, in the other one a detector simultaneously moves step by step in a homogeneous manner up and down. The density and the changing of the water content is calculated from the measured counting rate. The measuring time for each step is variable, but usually about 5–10 minutes are chosen. The difference in depth between the stations can also be varied.

The accuracy of the instrument in field use amounts to:

Water content changing: ± 0.0015 g/cm3

Soil density: ± 0.003 g/cm3

The solution power is such that horizontal layers of about 10 mm thickness can be distinguished in respect to the water content changing.
Zur Methodik des Bodengashaushaltes. II. Ergebnisse und Diskussion
Authors: Richter J.
Published: February 2007

The Evaluation of Soil Gas Ecology II: Results and Discussion.
Der Einfluß des NO3 : NH4 ‐Verhältnisses in der Nährlösung auf Ertrag und Gehalte an organischen und anorganischen Ionen von Tomatenpflanzen
Authors: Wehrmann J. , Merkel D.
Published: February 2007

The influence of the relation between NO3 and NH4 in the nutrient solution on yield and organic and inorganic ion contents of tomato plants..

Tomato plants were grown in aerated media of oppositly varying supply of (NH4)2SO4‐and NaNO3 with a constant N‐quantity of 15 meq/1 or a quantity of NH4‐, NO3 or (NO3 + NH4) increasing from 3 to 30 meq.N/1. Yield and ion content were determined.

A maximum yield was achieved by a mixed N‐supply i.e. 4 to 5 parts NO3, 1 part NH4‐N and 7, 5 meq N/l. The “(C‐A) value” was calculated by the content of the cationions “C” (=K+ + Na+ + Ca++ + Mg++ + NH4+) and the inorganic anions “A” (= NO3− + Cl− + H2PO4− + SO4–). The “(C‐A)” value is equivalent to the content of the organic anions. Furthermore we determined the citrate, malate, oxalate, and pektinate content. These make up 60–80% of the (C‐A) value.

The NO3‐ and K content increase considerably, the Ca‐, Mg‐, Na‐, Citrate, Malate and Oxalate content increase less pronounced, the Cl‐, H2PO4‐ and SO4‐ content decrease as the NO3 content increases from 0–80%.

If the medium contains 80–100% NO3 ‐ N, the NO3 and K content remain almost constant, while the Ca‐, Mg‐, citrate, malate and oxalate content especially increase in this case.

The K content decreases in the presence of a high (NH4)2SO4 supply. Parallel to this the value (C‐A) decreases greatly, so that it is less than the sum of the determined organic anions. In this case the content of organic anions obviously does not correlate with the (C‐A) value. The yield correlates with the carboxylate contents. (C‐A) values of 150–170 mval/100 gm. d. m. cause a lowering of the yield.

The plants contain an almost equal amount of citrate, malate and oxalate. Depending on the N‐concentration of the medium, the malate content will be a bit more than the amount of citrate in case of maximum yield.

If there is a lack or toxicity in the medium the citrate content will be higher than the malate content. The yield per dry weight correlates positivly with the quotients of citrate and malate.
Wettability of humic acid and its salts
Authors: Tschapek M. , Ardizzi G. Pozzo , de Bussetti S. G.
Published: February 2007

Homoionic humates are well wetted by hydrocarbons (apolar liquid) and water (polar liquid). By wetting with hydrocarbons low heats of immersion (or wetting) are registered, whereas by wetting with water high heats of immersion are registered and colloidal solutions are formed.

Humic acid is well wetted by hydrocarbons, producing low heats. It floats on the water surface, but once wetted by water it produces the heat of immersion. Studies of the properties of humic acid and humate permit to conclude that their surfaces are covered by hydrophilic and hydrophobic sites. By adsorption of butanol molecules it is established that humic acid and humate contain nearly two hydrophobic sites per 100 Å2.
Untersuchungen zur Translokation von Magnesium (28Mg) in Sonnenblumenpflanzen
Authors: Schimansky Chr.
Published: February 2007

Investigations on translocation of magnesium (28Mg) in sunflower plants.

1. The translocation and retranslocation of Mg respectively 28Mg in sunflower plants of different age have been investigated. The focus of this investigation was on the influence of the composition of the uptake solution and the age of plants on the uptake of Mg respectively 28Mg through the roots or through the leaves and on Mg translocation (distribution).

2. After sunflower plants were grown in Mg‐deficient 1/2‐Hoagland solution Mg in the plants were redistributed. The Mg in the roots, stems, cotyledons, primary and secondary leaves was retranslocated to the youngest leaves.

3. In isolated, secondary‐rooted sunflower shoots grown in Mg‐deficient solution, plant Mg was retranslocated into the new roots and into the youngest shoots.

4. The 28Mg‐uptake from the 0,2 mM MgSO4 solution was usually higher than from the 1/10‐Hoagland solution. The composition of the uptake solution had little influence on the distribution of 28Mg. Independent of the age plants had the highest 28Mg content in the young and the lowest in the old leaves.

5. Root uptake of 28Mg resulted in a more uniform distribution in the plant than leaf uptake. The old leaves had a higher 28Mg content by root uptake than by leaf uptake of 28Mg. This is probably influenced by transpiration, in combination with the xylem transport of 28Mg after root uptake, which differs from leaf uptake and translocation in basipetal direction.

6. With increased age of plants, the content of 28Mg/10 gr. fresh weight decreased and the difference in content between the parts of plant was higher. The decrease of Mg content in the oldest leaves was the highest.

7. The results showed that Mg was transportable in the phloem. The magnitude and the direction of Mg transport was determined as primarily through the assimilation stream, which is coupled with Mg transport in plants.
Einfluß einer Düngung auf den Diffusionsfluß nicht gedüngter Kationen
Authors: Grimme H. , Németh K.
Published: February 2007

Effect of Mineral Fertilizer Application on the Diffusion of Cations that have not been Added with the Fertilizer.

Mineral fertilizer application increases the concentration of all cations in the soil solution, because the cations added displace partly those cations occupying exchange positions into the soil solution. In pot experiments, therefore, the K concentration could be raised by Mg‐fertilization and vice versa.

In the first experiment the response of alfalfa to Mg fertilization was to be studied. 1.2 g Mg/pot (12 kg soil/pot) was applied before sowing and 0.5 g/pot after each cut. 1.0 g P/pot as CaHPO4 was added, but no K was added in the first year (except soil No. 6 K). In the 2nd year 1 g K/pot was added after each cut. At 3 sampling dates soil samples were taken for diffusion measurements.

In a second experiment K availability was tested at different K and soil water contents. 4 K treatments were included (0, 9, 29 and 49 mg K/100 g). K and Mg diffusion were measured.

In the first experiment an increase of K concentration in the soil solution was recorded (Tab. 1) and in the second one an increase of Mg concentration (Fig. 1). This increase of concentration took place without altering the amounts present in the soil, but it led to an increase of the diffusive flux of the cations in question (Tab. 1 Fig. 2).

This is taken as further evidence that cation diffusion takes place in the soil solution and depends mainly on the cation concentration in the soil solution.

In those cases in which the cation availability depends mainly on cation diffusion to the roots mineral fertilizer application may affect the supply of cations that have not been added to the soil.

This effect will be important in pot experiments to which large amounts of fertilizer are applied and which are not subject to leaching. It cannot be detected by most of the conventional soil testing methods because the amounts of cations ‐ except, of course, those that have been added ‐ have not changed. Only an analysis of the soil solution will reveal whether this „salt effect”︁ is significant or not in a specific case.
Auswirkungen von NaCl und Na2 SO4 auf Substanzbildung, Mineralstoffgehalt und Inhaltsstoffe bei Spinat und Salat
Authors: Matar Y. , Döring H. ‐W. , Marschner H.
Published: February 2007

Effect of NaCl and Na2SO4 on dry matter production, mineral content and organic compounds of spinach and lettuce.

In water culture experiments the effect of 2,5 meq and 25 meq NaCl and Na2SO4 respectively on dry matter production and content of mineral elements, chloroplasts pigments and carbohydrates in lettuce (salt sensitive) and spinach (salt tolerant) has been studied.

With increasing Na‐supply the dry matter production was decreased in lettuce and increased in spinach. With increasing Na‐supply in both species the content of K, Mg and Ca in the leaves decreased. This decrease was more pronounced with sulfate as accompanying anion (Na2SO4) and induced already deficiency in Ca and Mg. This induced deficiency of Mg was reflected especially in lettuce in lower contents of chloroplasts pigments.

In both plant species there was no effect of the Na salt treatments on the content of phosphorus or nitrogen in roots or leaves.

The carbohydrate content in both species was strongly affected by the Na salt treatments. Irrespectively of the accompanying anion this effect occured already at the low Na supply and before the dry matter production was influenced. In leaves and roots of lettuce the contents of glucose, fructose and sucrose was considerably decreased; this decrease was less expressed in the starch content. In spinach the Na supply only decreased the carbohydrate content in the roots whereas in the leaves especially the sucrose content was increased. This different effect of Na on carbohydrate content in spinach and lettuce could be an indication of different action of Na on carbohydrate metabolism, namely inhibited synthesis in lettuce and inhibited translocation in spinach.

The results demonstrate that in studies on the effect of increasing Na salt concentrations besides the osmotic effects also the ion specific effects have to be carfully considered. These ion specific effects are competition of Na+ with other cations during uptake and the influence of Na on the cell metabolism, especially on the pathway of carbohydrates.

The authors thanks Mrs. Hwie Juen Tjandraatmadja for her engaged help in various laboratory works.
Pyrolysis gas chromatography of humic substances from different origin
Authors: Martin F.
Published: February 2007

Pyrolytische Gaschromatografie von Huminstoffen unterschiedlichen Ursprungs..

Die Pyrolyse von Huminstoffen liefert unter anderen niedrig siedenden Substanzen Alkane und Olefine, deren Anteil bei Fulvo‐ und Huminsäuren unterschiedlich ist. Diese Verbindungen entstehen durch Radikalreaktionen aus aliphatischen oder alicyclischen Ketten; ihre Bildung wird zum Teil durch den Aschegehalt der Huminstoffe katalytisch beeinflußt. Nach dem Erhitzen von Huminstoffen an der Luft werden weder Alkane noch Olefine pyrolytisch gebildet.
Der Einfluß von Bor auf das Kationen‐Anionen‐Gleichgewicht von Tomatenpflanzen
Authors: Merkel D.
Published: February 2007

Influence of Boron on the Cation Anion Balance in Tomato Leaves.

Tomato plants were grown in nutrient solutions containing 10‐3 to 1 ppm B. Maximum yield was obtained at 10‐1 ppm B. Boron deficiency resulted in a yield depression of about 60%. The boron content of the leaves increased from 5 ppm at low to 89 ppm at high boron supply. Nitrogen and ion contents of the leaves were affected by boron deficiency in the following way: 1. Total and organic N, K. the sum of cations, and the sum of inorganic anions were depressed. 2. The (C‐A)‐value, i.e. the toal content of organic ions, remained almost unchanged. The citrate and malate contents were increased, oxalate and pectinate decreased. .

In plants of adequate boron supply the amount of organic nitrogen and sulphur exceeded the organic anion content by 97 to 114 meq./100 grs.d.m., — in deficient plants only by 25 meq. This is explained by the assumption that the transport of carboxylates from the leaves to the root via phloem is reduced by B‐deficiency.
Infiltration von Tritium‐markiertem Wasser in zwei tiefgelockerten Graulehm‐Pseudogleyen
Authors: Schröder D. , Scharpenseel H. W.
Published: February 2007

Infiltration of Tritium‐labelled water in two subsoil loosened greyloam‐pseudogleys.

On two greyloam pseudogley‐soils, subsoil loosened in 1961 tests, based on the use of truncated cylinders, could not beyond any doubt prove an amelioration of water permeation. Recently conducted investigations, using tritium labelled water demonstrated more distinctly, that water is percolating through the loosened parts faster and in larger quantities than through the unloosened more compacted ones.
Die Verwitterung mafischer Chlorite
Authors: Schwertmann U.
Published: February 2007

The Weathering of Mafic Chlorites in Soils (A Review)

Recent results from the literature and some own data on chlorite weathering as derived from soil profile studies and laboratory work on artificial weathering are summarized. Among the two possible pathways of chlorite weathering ‐ vermiculitization after removing the hydroxide layer and complete dissolution ‐ vermiculitization appears to occur in rather “closed” systems not too acid and poor in organic compounds (e.g. saprolites). Complete dissolution, on the other hand, prevails in strong acid parts of the solum rich in organic matter, e.g. in podzol A horizons. Due to the presence of micaceous minerals in most profiles which also serve as a source for expandable mixed layer species the exact pathway of the chlorite during weathering cannot be followed up easily.
Bildung sekundärer Al‐(Fe‐)Chlorite
Authors: Blum W.
Published: February 2007

Genesis of Secondary Al‐(Fe‐)Chlorites

Comparing the results of soil investigations with those obtained from laboratory syntheses it was concluded that secondary Al‐Fe‐chlorites in soils of moderate cool‐warm‐humid climates mainly develop through protonisation of Al and Fe in the mineral structure of expanded dioctahedral vermiculites with subsequent hydrolysis in the interlayer space. In this process characteristics of the mineral itself (e.g. layer charge) as well as carbonic acid and soil organic acids (as proton suppliers) are the most important factors.

From this, the further conclusion was drawn that in the pH‐range 6, 5–6 secondary chlorites begin to develop increasingly until pH5 (development conditions) and in the pH‐range 5–4,5“conservation conditions” exist. ‐ At pH<4,5 secondary chlorites are unstable (dissolution conditions) through protonisation of Al‐Fe‐hydroxy polymers (reverse of hydrolysis) with subsequent solubilization and leaching especially through complexation by soil organic acids. ‐ As remaining minerals in this weathering sequence smectites occur, resulting from the decrease of layer charge in vermiculites through the chloritization process, thus indicating that chloritization may be an important process for the genesis of smectites under acid weathering conditions.
Verteilung von Stickstoff auf Sproß und Wurzel bei jungen Bohnenpflanzen nach der Aufnahme von NO und NH
Authors: Martin P.
Published: February 2007

Translocation of nitrogen to the shoot of young bean plants after uptake of NO and NH by the root

Phaseolus vulgaris plants (var. nana, cv. Saxa) at the primary leaf stage (without nodules) were fed during 6 hours with 15NO and 15NH, respectively. 24 hours after the absorption period more 15N from the absorbed NO was translocated from the root to the shoot. The presence of NH in the nutrient solution enhanced the translocation of 15NON, probably by an inhibition of nitrate reductase. NH4‐+15N is mainly retained in the root by a high incorporation into the root protein. It can be concluded that nitrogen from newly absorbed NO is not retained and used for protein synthesis in the root according to the root's potential to synthesize protein. Nitrate reduction in the root is considered to be the limiting factor. This is supported by the fact that withdrawal of NO in the nutrient solution prior to the 15N‐experiment increased NOtranslocation to the shoot as a consequence of a lowered level of nitrate reductase. In an experiment with 14NOsupply to the roots and 15NOapplication to the primary leaves (infiltration method) a considerable amount of 15N was translocated from the leaves to the roots. This indicates that an insufficient NOreduction in the root can be substituted by a retranslocation of reduced N‐compounds from leaves to the roots. The proportion of NO reduced in the root influences also the pattern of primary distribution of nitrogen in the shoot of plants at the 4 leaf stage. At a concentration of 0,2 meq/l NO in the nutrient solution as compared to 20 meq/l NO during 10 hours a relative higher amount of 15N was transported from the root to the younger, growing leaves i.e. via the phloem to metabolic sinks.
Nitrogen distribution studies by emission spectrometry in free amino acids and amides of developing panicle of rice
Authors: Muhammad Shah , Kumazawa Kikuo
Published: February 2007

Studien zur Stickstoffverteilung durch Emissions‐Spektrometric in freien Aminosäuren und Amiden junger Reisrispen

Die Verteilung von Ammonium‐ und Nitrat‐Stickstoff auf die freien Aminosäuren und Amide junger, sich entwickelnder Reisrispen (Oryza sativa L.) wurde nach Aufnahme durch die Wurzeln ermittelt. Dabei erfolgten die Auftrennungen der Aminosäuren und Amide durch Dünnschicht‐Chromatographie und die 15N‐Bestimmungen mit Hilfe der Emissions‐Spektrometrie. In den Reisrispen fanden sich große Reserven an Asparagin, Glutamin und Glutaminsäure. Die 15N‐Anteile in freien Aminosäuren und Amiden waren bei Zufuhr von 15N‐Ammoniumionen höher als bei entsprechender Ernährung mit Nitrat. Glutaminsäure enthielt einen wesentlich höheren Anteil an 15N‐ und an Gesamt‐Stickstoff als jede andere Aminosäure, was als Hinweis auf die zentrale Bedeutung der Glutaminsäure für die Synthese der übrigen Aminosäuren aufgefaßt wurde. Allgemein waren für Aminosäuren, die primär oder sekundär im Krebs‐Zyklus entstehen, hohe Einbauraten festzustellen, und Aminosäuren mit niedrigem metabolischen turn‐over zeigten geringeren Einbau; dies gilt sowohl für das Angebot von 15NH als auch für 15NO.
Calciumgehalte in Früchten von Paprika, Bohne, Quitte und Hagebutte im Verlauf des Fruchtwachstums
Authors: Mix G. P. , Marschner H.
Published: February 2007

Calcium content in fruits of paprika, bean, quince and hip during fruit growth

The Ca content and the Ca translocation into the fruits during their growth was determined in paprika and bean under controlled conditions (nutrient solution, growth room) and in quince and hip (Rosa rugosa Thumb.) under field conditions.

Compared to leaves the Ca content in the fruits is very low in all 4 species and declines further during their growth. The K content, however, is similar in the leaves and in the fruits of all 4 species and remains nearly constant during fruit growth. The low Ca content of the fruits cannot directly be related to the cation exchange capacity (CEC) as there are no differences in the CEC between leaves and fruits.

The generally low Ca content of the fruits and its decline during fruit growth is causally related in all 4 plant species to the low rate of Ca translocation compared to the rate of dry matter translocation into the fruits.

There are, however, distinct differences between the 4 plant species in the course of the ratio Ca/dry matter translocation into the fruits: In paprika the Ca translocation into the fruits strongly declines during fruit growth and in bean the Ca translocation practically ceases with the onset of seed growth. In quince under field conditions the Ca translocation into the fruits rapidly declines at later stages and finally a translocation of Ca out of the fruit takes place (decrease in the amount of Ca/fruit). Only in hip the Ca translocation into the fruits remains constant during fruit growth. There is, however, a distinctly different distribution of Ca to the various parts within the hip fruits.

The decline in Ca translocation during fruit growth can be explained in paprika and bean with a shift in water influx from the xylem (rich in Ca) to the phloem at the stage of high rates of dry matter influx into the fruit. In quince and hip, however, additional mechanisms (alternating water flux in the xylem, CEC) seem to be involved in the regulation of the Ca content of these fruits.
Differenzierung oxalatlöslicher Eisenoxide
Authors: Fischer W. R.
Published: February 2007

Differentiation of oxalate soluble iron oxides

According to their mode of formation the oxalate soluble Fe(III)‐oxides show different rates of dissolution especially within the first 30 min of oxalate extraction.

Precipitates formed by bacterial or oxidative decomposition of ferric citrate have a very high dissolution rate with more than 90 percent being dissolved within 30 min.

Ferrihydrites prepared by alkaline hydrolysis of Fe(III) salts, after slow drying, dissolve to about 60 to 80 percent within this period, whereas similar products quenched with liquid N2 dissolve more rapidly. A plot of (Fe30/Feo) vs. (Feo/Fed) allows to draw a boundary line between the field of podzol values and the field of the other pedogenic iron oxides, as from brown earths and black earths (chernozems).
Einfluß der Frucht auf Photosynthese und Atmung
Authors: Lenz F.
Published: February 2007

Fruit Effect on Photosynthesis and Respiration

Several investigations about fruit effects on photosynthesis and respiration, mainly of Citrus madurensis (Lour.) and Solanum melongena (L) plants are reviewed.

Fruiting plants had higher photosynthetic rates (mg CO2 · dm−2 · h−1) than non fruiting ones, particularly during stages of most intensive fruit growth. The photosynthetic rates could be stimulated by increasing fruit temperatures.

No differences in dark respiration rates of fruiting and non fruiting plants were observed. However photorespiration was considerably higher in non fruiting plants as compared to fruiting ones. Leaves of non fruiting plants accumulated more sugars and starch in the leaves during the light periods than fruiting ones.

The gaseous diffusive resistance of leaves was higher in non fruiting as compared to fruiting ones.

The higher photosynthetic efficiency of fruiting plants is probably controlled by several mechanisms, some of which were discussed in the paper.
Molecular weight as influencing factor on the adsorption of dextrans on sodium and calcium montmorillonite
Authors: Guidi G. , Petruzzelli G. , Giachetti M.
Published: February 2007

Der Einfluß des Molekulargewichtes auf die Adsorption von Dextranen an Natrium‐ und Calciummontmorilloniten

Sechs Glukosepolymere, deren Molekulargewicht von 10.300 bis 1.960.000 anstieg, wurden von Natrium‐ und Calciummontmorilloniten aus wäßrigen Lösungen adsorbiert. Bei 27°C folgten die Adsorptionsisothermen der Langmuir‐Gleichung. Die Langmuir‐Konstanten, a' (Adsorptionsmaximum) und, b' (Bindungsenergie) wurden berechnet. Ebenso wurden aus den Werten für die Langmuir‐Konstante, a' die maximal von Dextranen bedeckte Oberfläche berechnet.
Chemische Veränderungen am Lignin bei dessen Isolierung
Authors: Ziechmann W. , Weichelt Th.
Published: February 2007

Chemical alterations on lignin during its isolation

Different methods to isolate lignin from straw (Triticum aestivum) and wood (Picea axcelsa) were investigated.

Yields, methoxyl contents as well as absorption spectra in the ultraviolet, visible and infrared region and in addition color reactions by phloroglucin/HCl indicated quite a lot of chemical alterations of the constitution of various lignins.

The methods by Björkman (1956) and Pepper et al. (1959) reached the aims of isolation best. But Björkman‐Lignin had some impurities from carbohydrates, while the radical content may be unnatural high and the molecular‐weight too low. Although the method by Pepper et al. caused many irreversible alterations on lignin when the extraction time was too long (> 1h) and no N2‐atmosphere was used, this method is quite convient to isolate lignin if these mistakes are avoided.
Clay minerals as heterogeneous catalysts in preparation of model humic substances
Authors: Wang Thomas S. C. , Li Song Wu
Published: February 2007

Huminstoffbildung unter katalytischer Einwirkung der Tonminerale im Modellversuch

In Gegenwart von Tonmineralien und Quarz verläuft die oxydative Polymerisation von Protocatechusäure zu Huminstoffen. Fulvosäuren treten hauptsächlich in der Lösungsphase auf, während Huminsäuren mit dem Bodensatz niedergeschlagen werden. Die Polymerisation wird von Abbau‐ und Mineralisierungsprozessen der verschiedenen organischen Zwischenprodukte begleitet, die über oxydative Ringsprengungen verlaufen. In ihrer katalytischen Wirkung ließen sich die Minerale in die Reihe Illit > Montmorillonit > Kaolinit > Quarz einordnen. Der Mechanismus der Katalyse wird diskutiert.
N2‐Fixation by roots and rhizosphere of sand dune plants
Authors: Ahmad M. H. , Neckelmann J.
Published: February 2007

Nitrogenase activity (by acetylene reduction assay) has been found on the roots and in the rhizosphere‐soil of various plant species collected from dune soils (Table 1.) located on the west coast of Denmark. Out of twelve plant species, five plant species (Deschampsia flexuosa, Ammophila arenaria, Calluna vulgaris, Empetrum nigrum and Corynephorus canescens) revealed a positive nitrogenase activity. Among these five, three were temperate grasses. Except Ammophila arenaria, all four plant species were collected from old sand dune and showed nitrogenase activity on roots as well as in their rhizosphere soil, Ammophila arenaria was collected from fresh sand dune and exhibited nitrogenase activity only on roots (Table 2).
Symptome von Mangan‐Überschuß bei Bohnen (Phaseolus vulgaris)
Authors: Horst W. J. , Marschner H.
Published: February 2007

Symptoms of manganese toxicity in beans (Phaseolus vulgaris L)

In water culture experiments with bush bean plants (Phaseolus vulgaris L. var. „Red Kidney”︁) the macro‐ and micro‐symptoms of manganese toxicity had been studied.

Typical symptoms of Mn toxicity are small distinct blackish‐brown spots, first at the older leaves and at more severe toxicity also at the petals and stems. Using the autoradiographic technique on 54Mn‐distribution and comparing this with corresponding light microscopic studies it could be demonstrated that the blackish‐brown spots in the leaves resemble Mn‐precipitations.

These precipitations are Mn‐compounds of higher oxidated form and are primarily localized in the walls of cells in vicinity of the vessels. The extend to which these precipitations occur is not only a function of the Mn‐content of the leaves but also of their age. At comparable Mn‐content the extend of the precipitation increases with the leaf age.

As secondary symptom of Mn‐toxicity under certain conditions (presence of silicon e.g.) induced Fe deficiency (chlorosis of the youngest leaves) and Ca deficiency („crinkle leaf”︁) may occur.

It is assumed that the process of Mn precipitation within the leaves is enzymatically regulated. The severe reduction in the growth of leaf blades at Mn toxicity is presumably related to an interference with the growth hormon balance.
Untersuchungen zum Bodenlufthaushalt in einem Bodenbearbeitungsversuch. 2. Gasdiffusionskoeffizienten als Strukturmaße für Böden
Authors: Richter J. , Großgebauer A.
Published: February 2007

Investigation of the soil gas regime in a tillage experiment: 2. Apparent diffusion coefficients as a measure of soil structure

In a soil tillage experiment with nursery stock on three different soils the apparent diffusion coefficients for CO2 were measured using soil cores of different depths at different times. Not‐tilled, herbicide treated plots were compared with rototilled plots.

The relationship between the relative apparent diffusion coefficient and the air content may be described by an exponential regression function Ds/Da = 0.0085 · e6.8EL, if all measurements are taken into the calculation. By dividing into different soil textures different regressions are obtained for the three studied soils: a sand, a silt and a clay loam. In many cases it is possible to show by the changing Ds(EL) regression changes of the soil structure with depth or as a result of tillage. In all these cases the soil of the not tilled plots turns out to be better structurized than that of the tilled ones, demonstrated by higher Ds‐values at equal EL.

The interpretation of the differences is being tried with the aid of soil pore tortuousity and continuity. Finally the measured Ds(EL) relationships are applied to characterize the soil gas regime for two seasons, using CO2 concentration profiles of the soil air on a day in summer and fall, respectively. It is shown, that CO2 production reaches farther down in summer than in fall.
Anorganisch‐katalytische Umsetzungen von Cyanamid und dessen Metaboliten in Quarzsand I. Mechanismus des Cyanamidabbaues unter dem Einfluß von Eisenoxiden und Feuchtigkeit
Authors: Amberger A. , Vilsmeier K.
Published: February 2007

Inorganic catalytical transformation of cyanamide and its metabolites in quartz sand I. Mechanism of cyanamide breakdown as influenced by iron oxides and moisture

A study was made of the inorganically catalysed breakdown of cyanamide by iron oxides in quartz sand, and the formation of metabolites in relation to the type of iron oxide and the moisture level in the system. The possibility that cyanamide breakdown was biological and enzymic was largely eliminated.

In the absence of iron oxides the added cyanamide was practically unchanged over the 100 days of the experiment.

With the addition of iron oxides such as amorphous Fe(III)‐hydroxide, ochre or rust, the cyanamide rapidly took up water after a few hours and urea was formed. Water uptake was dependent on the type of iron oxide added. When the moisture level in the reaction medium was low (5% of the total water capacity) the process was accelerated.

Different amounts of dicyanamide and guanylurea were produced depending on the iron oxides applied. When the water content was high, reactions leading to the production of these compounds were slowed down.

The inorganically catalysed breakdown of cyanamide depends on reaction conditions. It can result either in the uptake of water to produce urea directly or in the production of dicyanamide which gives rise to guanylurea by the further addition of water.
Q/I relations and electroultrafiltration of soils as measures of potassium availability to plants
Authors: Grimme H. , Nair P. K. R.
Published: February 2007

The equilibrium activity ratio (ARo) of soil potassium and the K extracted by electroultrafiltration (EUF) within a desorption time of 10 min (EUF10) were compared as measures of K availability indicated by K uptake and dry matter yield of barley plants grown in four soils receiving different rates of K fertilization in a glasshouse experiment. As could be expected, both methods indicated that K intensity in soils increased with higher amounts of K dressings and decreased with progressive crop growth. With EUF10, 56–77% of the variation in plant response in dry matter yield and K uptake could be explained, where as with ARo, it was only 36–65%. There was good linear correlation between ARo, and EUF10 for a particular soil; but there was differential variation in the two parameters for the different soils. When compared on the basis of plant response, EUF10 was found to better describe K availability to plants and differentiate better between soils of different K selectivity.