Vergleich deutscher und schweizer Regensimulatoren - Einfluß der Regeneigenschaften auf die Bodenoberflächenrauhigkeit

Comparison of German and Swiss Rainfall Simulators - Influence of Rainfall Characteristics on Soil Surface Roughness Six different field rainfall simulators were compared. Soil surface roughness was tested by a simple field method before and after rainfall simulation. Preparation of the test site with a rotary cultivator inadvertently entailed spatial variability of roughness and aggregate size. Thus, the plots with finer seedbed showed higher runoff and soil loss. The relative decrease of roughness could best be correlated with the total kinetic energy as well as with the R factor of the different simulators (r = 0.87 resp. 0.91). Thus, the degree of soil surface leveling was shown to be due to the rainfall characteristics of the different simulator types. However, there was no relation between change of soil surface roughness and runoff. The relative classification of the kinetic energy of the rainfall simulators explained the leveling of the soil surface better than the classifications previously used in many studies (r = 0.91 as against r = 0.73).     

Ein Vergleich der Huminstoffsysteme einer Parabraunerde aus der Kölner Bucht und einer österreichischen Schwarzerde

A comparison of the humic systems from a Luvisol from the area of Köln and from an Austrian Chernozem Grey humic acids, brown humic acids and fulvic acids have been extracted from a Luvisol after removal of the “light fraction”. The humic fractions were investigated chromatographically using controlled pore glass with a pore diameter of 17,7 nm. Concentration of both coloured material and carbon were simultaneously recorded in the chromatograms. Specific extinctions at 400 nm were calculated and maximal values were taken as constants specific for “pure” humic substances. These were 349,6; 155,8 and 39,4 for “pure” grey humic acids, brown humic acids and fulvic acids, respectively, and were in part considerably below those determined earlier for an Austrian Chernozem. Using these constants “pure” humic substances could be distinguished numerically from accompanying non-humic substances. The ratio of “pure” humic to non-humic substances was approximately 2:1 for both soils. Within the “pure” humic substances Chernozem humus was dominated by grey humic acids amounting up to 52% whereas in the Luvisol brown humic acids had the same level.     

Ein Vergleich und eine Bewertung von Dränformeln für die Drändistanz von geschichteten Grund- und Stauwasserböden

A comparison and an evaluation of drain spacing equations for layered soils Drain spacings, calculated with different steady-state tile drainage formulas for layered soils, were compared. The formulas under consideration were those of Ernst, van Beers and of Toksöz and Kirkham. It was found that, for certain ranges of the drainage parameters, the drain spacings compare well. For other conditions, differences of over 100 percent did occur. Especially, results obtained with the Ernst equation may deviate considerably from those of the other authors. However, also drain spacings calculated with the van Beers equation do occasionally differ from those of Toksöz and Kirkham. For practical use the equation of Toksöz and Kirkham is recommended.     

Vorstellung der SrCl2-Methode nach Bach zur Bestimmung der effektiven Kationenaustauschkapazität und Vergleich mit der NH4Cl-Methode

Presentation of the SrCl₂-method after Bach for the determination of the effective cation exchange capacity and comparison with the NH₄Cl-method The SrCl₂-method for the determination of the effective cation exchange capacity CEC_eff has been developed by Dr. H. Bach, a former geochemist of the “Geologisches Landesamt Schleswig-Holstein”. Exchangeable metallic cations in soils are displaced by a 0, 1 M SrCl₂-solution and analyzed from the percolate. Reexchange of strontium by a 0, 1 M MgCl₂-solution allows to determine the CEC_eff by analyzing for strontium in the second percolate. In comparison with the customary application of NH₄Cl, SrCl₂ shows the following advantages:

• 1 The nearly unbuffered SrCl₂-solution adopts instantly the pH of the soil.
• 2 In contrast to the weakly acid NH₄Cl-solution, no H₃O⁺-cations compete with the exchange cation. Furthermore, partial dissolution of clay minerals is prevented because of the near-neutral character of the SrCl₂-solution.
• 3 The SrCl₂-method can be applied on all types of soils including carbonate- and salt-bearing soils.
• 4 The amount of free (dissolved) cations can be approximated.

     

Bestimmung von hydraulischen Parametern für die Wasserhaushaltsuntersuchungen im natürlich gelagerten Boden. Ein Vergleich von Feld- und Laboratoriumsmethoden

Determination of hydraulic parameters to estimate water movement and water storage in undisturbed soil. A comparison of field and laboratory methods. The soil moisture characteristics and the unsaturated conductivity were measured under field and laboratory conditions. In an undisturbed soil monolith in continous connection with the underlying loess-soil-layer 60 tensiometer and a neutronprobe-accestube were used respectively to determine the matric potential and water content changes during a transient drainage experiment. Within the matric potential range of 0 to approximately ?50 to ?100 mbar the soil moisture characteristics determined in the laboratory and in the field are substantially different. When the matric potential is more negative than ?100 mbar the slope of these curves and hence the specific moisture capacities are relatively well comparable. The field-measured conductivity functions differ considerably from those values which were either measured under lab-conditions or computed from the soil moisture characteristics data. The conductivities are expressed as a function of the matric potential which is possibly the major reason for these remarkable differences. However, the changes in water content in this dense silty clay loam are too small to express the unsaturated conductivity as a function of the absolute water content. The most serious problems in extrapolating the results of the less time consuming laborcalculation methods to field conditions arise in that range of matric potentials where water movement is significant.     

Bodenkundlicher Vergleich von Kultur- und Brachland im Schweizer Jura

Comparison of soil properties in agricultural and abandoned fields in Swiss Jura Changes of physico-chemical soil properties occurring after abandonment of agricultural fields were investigated at 14 north exposed locations situated between elevations 500 and 900 m in the Jura mountains of Switzerland. These old fields were compared with adjacent fertilized and non-fertilized meadows. All investigated soils were silty clay loams of the type slightly acid brown earth. In old fields the real density remained unchanged but the bulk density decreased significantly to a depth of 20 cm and with it, the soil water content increased. The pH fell from about 6 to 5 probably due to increased leaching, large production of plant litter and different decomposition of soil organic matter. The increase of C/N-ratio in abandoned fields from 10 to 15 further contributes to the deterioration of the site. The absence of fertilization and important N-fixing plants may be the major reasons why soils in old fields are poorer in nitrogen. In spite of the fact, that the entire primary production is left on the field, the organic carbon content mostly decreased upon abandonment of the meadows.     

Kultur vonHordeum vulgare in Erde und in Hydroponik — ein Vergleich

Zusammenfassung Kulturen vonHordeum vulgare in Nährlösung (Hydroponik) waren im vegetativen Wachstum sowie im Kornertrag solchen in Erde überlegen.

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Culture ofHordeum vulgare in earth and in Hydroponic — a comparison

Summary Hordeum vulgare L. had greater matter-production and more corn grains. per plant when cultivated in nutrition solution than in earth.

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Hordeum vulgare

() .

     

Vergleich von Nitrat- und Amino-N-Schnelltest zur Charakterisierung des Stickstoff-Versorgungsgrades von Winterweizen

Comparison of the rapid tests for nitrate and amino-N for evaluating the N-status of winter wheat Nitrogen fertilizer trials with winter wheat were conducted in 1985 and 1986 to compare the efficacy of the rapid test for nitrate (in the stem base) and a newly developed rapid test for amino-N (in fully expanded green leaves) for evaluating the N-status of plants. In addition, the influence of weather conditions on the results given by both tests when using ammonium nitrate (NH₄NO₃ + CaCO₃) (AN) and urea-ammonium nitrate solution (UAN), was evaluated to determine wether the rapid test for amino-N gives more accurate information on the N-status of winter wheat than the rapid test for nitrate. The results show that the rapid test for nitrate is suitable to characterize the N-status of winter wheat when nitrogen is predominantly taken up by roots as nitrate. This is normaly the case when plants are fertilized with the salt form of nitrogen, als well as with liquid fertilizer, such as UAN applied through tubes in the soil, as for fertilization of winter wheat at later growing stages. However, during dry weather (1986 field trial) UAN application on leaves at shooting and ear emergence can result in high nitrogen uptake by leaves, causing an underestimation of plant N-status by the rapid test for nitrate, and thus, subsequent excess N-fertilizer application may be recommended (order of magnitude: 20 kg N/ha). Under these conditions the rapid test for amino-N in leaves (pressed sap) is a more accurate test for estimation of plant N-status because it determines glutamine and amino acids, the most important storage forms of reduced nitrogen in plants. When UAN fertilizer on leaves is washed off by rain (1985 field trial), crop N-fertilizer requirements predicted by both tests are comparable. If storage of nitrate in the stem base occurs, due, for example to low radiation intensity during spring (lower nitrate reduction), with the rapid test for amino-N an underestimation of plant N-status can be obtained.     

Ein Vergleich von Eisenpodsolen im östlichen Niedersachsen mit Podsolen unter borealem Nadelwald in Finnland

Iron podzols in eastern Lower Saxony compared with podzols under finnish boreal Pine forests Well developed iron podzols with orange-brown Bs-horizons poor in humus are found in isolated small areas of eastern Lower Saxony. Because of their similarity they were compared with finnish podzols under boreal pine forest. Similar soil morphology, low humus illuviation and unconsolidized Bs-horizons are common to both groups of podzols. Different are the smaller thickness of soil horizons and the higher amounts of Fe-oxides in B-horizons of finnish podzols. Despite high grade of activity (Fe_ox/d) this may be due more to iron oxide formation by silicate weathering (micas) than to podzolization. An interpretation of the german podzols as relics from boreal coniferous forests may be supposed but there is no significant evidence by the considered datas.     

Adsorption von Wasser, Äthylenglycolmonoethyläther sowie Stickstoff und ihre Beziehung zu Eigenschaften deutscher und israelischer Bodenproben

Adsorption of Water, Ethylene Glycol Monoethyl Ether as well as Nitrogen and its Relation to Properties of German and Israeli Soil Samples To determine the specific surface area, samples taken from 140 soil horizons were selected and the significant physical and chemical properties were investigated. The specific surface area of the samples was determined by adsorption of H₂O, ethylene glycol monoethyl ether (EGME) and N₂. A comparison of the three methods shows that the specific surface area determined by the adsorption of H₂O and EGME does not differ significantly. However, the specific surface determined by N₂-adsorption differs markedly from the results obtained using the polar substances. As a dependent variable the specific surface area is mainly influenced by the clay content and clay mineral type. Further, the organic substance content as well as the iron- and manganoxide content have a more significant influence on the specific surface area the lower the clay content is, or the content of three layer minerals. As an independent variable, the specific surface area determined by adsorption of EGME, proved to be the characteristic soil factor which reflects the effective cation exchange capacity as well as the hygroscopicity with the highest degree of accuracy.     

Bodenatmung,Stickstoffmineralisation und Humusabbau ostafrikanischer Böden nach Trocknung und Wiederbefeuchtung

Soil respiration, nitrogen mineralization and humus decomposition of East African soils after drying and remoistening Soil respiration and nitrogen mineralization of 51 East African cultivated, savanna and forest soils were compared after 3 and 21 weeks of air drying. The average soil respiration after 21 weeks of drying was 1.221 ± 0.106 times higher than that after 3 weeks of drying whereas the average nitrogen mineralization was not increased significantly (factor 1.132 ± 0.256). The increase in soil respiration was correlated positively with the water soluble organic matter. During air dryings of 3 days and moist incubations of 4 days at 30°C, which were repeated 20 times in 10 soils, 3–10% of the organic carbon and 8–19% of the organic nitrogen (low humus vertisol 69%) were mineralized. Changes in the amount and the extinction of humic and fulvic acids were considered to be indicative for an increased humification during the drying and remoistening of soils.     

Vergleich zwischen Total- und königswasserextrahierbaren Elementgehalten in natürlichen Böden und Sedimenten

Comparison between total- and aqua regia extractable contents of elements in natural soils and sediments Total- and aqua regia extractable contents of 19 elements from 28 soil samples with widely varying composition of the ISE ring analytical program (INTERNATIONAL SOIL-ANALYTICAL EXCHANGE) of the year 1995 to 1997 have been taken to find out the comparability between the two fractions. The relations between the two fractions and pH, organic matter and clay content were considered by means of single and multiple regressions. The correlations between the total and aqua regia extractable contents of As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, P, Pb and Zn are very close, whereas Al, Ba, K, Na and Sr are not or only weakly correlating. The multiple regressions show that the content of some aqua regia extractable elements and the proportion (in %) of the total contents is correlated with pH, organic matter and/or content of clay. In the same way the proportion of aqua regia extractable elements is closely related (except Fe and Hg) to the soil pH. Hereby the proportion of the aqua regia extractable content increases with increasing pH in the range 3,5—7,7. The determined equations are tested for As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn by using the values of certified reference material. The estimated aqua regia extractable contents are being compared with values of reference material. The average proportion of the calculated to the measured aqua regia contents of an element in percent are 99 for Zn, 98 for Co, Cu and Mn, 94 for Cd, 90 for Ni, 88 for Cr, 105 for Hg, 113 for As and 114 for Pb.     

Vergleich der mutagenen Wirkung von N-Nitroso-N-Methylharnstoff, Äthylmethansulfonat und Röntgenstrahlen bei Gerste

Zusammenfassung Nach Saatgut-Behandlungen von Gerste wurde die mutagene Wirksamkeit von N-Nitroso-N-Methylharnstoff (NMH) im Vergleich zu Äthylmethansulfonat (ÄMS) und Röntgenstrahlen bestimmt.Eine Analyse der röntgenstrahleninduzierten Chromosomenaberrationen im ersten Mitosezyklus der Keimung zeigte, daß die Meristemzellkerne des für die Versuche verwendeten Saatgutes ausschließlich im G₁-Stadium der Interphase arretiert waren.Die mutagene Effizienz von NMH entspricht etwa der von ÄMS; seine molare Aktivität ist dagegen um einen Faktor von rund 80 erhöht. Auf der Basis vergleichbarer Frequenzen von Chlorophyllmutanten induziert NMH signifikant weniger sichtbare Chromosomenaberrationen als ÄMS, jedoch eine gleich hohe M₁-Sterilität. Reziproke Translokationen zwischen nichthomologen Chromosomen sind sowohl nach NMH- als auch nach ÄMS-Behandlung im Gegensatz zur Röntgenbestrahlung nicht die Hauptursache der M₁-Sterilität.Zwischen den NMH- und ÄMS-induzierten Chlorophyllmutationsspektren sind keine signifikanten Differenzen nachweisbar. In der Relation von Chlorophyll-zu vitalen Mutationen (nurerectoides undeceriferum ausgewertet) bestehen zwischen beiden Agenzien ebenfalls keine Unterschiede. Eine Abhängigkeit der Chlorophyllmutationsspektren vom Sterilitätsgrad der M₁-Ähren konnte nicht nachgewiesen werden. Dagegen führte ein Vergleichsanbau der M₂-Generation im Gewächshaus und im Freiland zu signifikant verschiedenen Spektren. Nach NMH-Behandlungen wurde Homogenität zwischen dem Phänotypenspektrum (albina, xantha, viridis) der in der M₁-Generation auftretenden chlorophylldefizienten Sektoren und dem Chlorophyllmutations-spektrum in der M₂-Generation nachgewiesen.Bestimmungen der Frequenzen von Chlorophyllmutationen in Abhängigkeit vom Sterilitätsgrad der M₁-Ähren innerhalb je einer Behandlungsvariante ergaben, daß sowohl für NMH als auch für ÄMS die Mutationsfrequenzen mit steigendem Sterilitätsgrad zunahmen.Die quantitativen Beziehungen zwischen verschiedenen M₁- und M₂-Kriterien wurden untersucht und im Detail diskutiert. In den Beziehungen von M₁-Wachstumsreduktion zu M₁-Tötungsraten konnten für NMH, ÄMS und Röntgenstrahlen keine signifikanten Unterschiede nachgewiesen werden. Alle anderen Relationen wichen nach Röntgenbestrahlung im Vergleich zu den Behandlungen mit den mutagenen Chemikalien signifikant ab. Signifikante Unterschiede zwischen NMH and ÄMS wurden in den Beziehungen der verschiedenen Kriterien zu den Frequenzen der Chromosomenaberrationen im ersten Mitosezyklus der Keimung gefunden. Unterschiede zwischen NMH und ÄMS bestehen auch bezüglich der Toxizität ihrer Hydrolyseprodukte. Langlebige, radiomimetisch aktive oder toxische Hydrolyseprodukte konnten für NMH nicht nachgewiesen werden.Die Ergebnisse der Versuche zeigen, daß NMH für Mutationsversuche mit angewandter Zielstellung gut geeignet ist und gegenüber dem bisher bevorzugten ÄMS gewisse Vorteile bietet.

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Comparison of the mutagenic action of N-nitroso-N-methylurea, ethylmethanesulfonate, and X-rays in barley

Summary The mutagenic effects of N-nitroso-N-methylurea (NMU), ethyl methanesulfonate (EMS), and X-rays on seeds of barley were studied.An analysis of the types of X-ray induced chromosome aberrations in the first mitotic cycle of germination indicated that the meristem cell nuclei of the used seed material were arrested exclusively at the G₁ stage of interphase.On the basis of maximum frequencies of chlorophyll-deficient M₂ seedling mutants the mutagenic efficiency of NMU is as high as that of EMS, whereas its molare activity is about 80 times the activity of EMS. At corresponding chlorophyll mutation frequencies NMU induces only about one third visible chromosome aberrations as compared to EMS. Nevertheless, both agents induce comparable degrees of M₁ sterility. As opposed to X-irradiation, both chemicals induce only low frequencies of chromosomal interchanges which therefore cannot be a major cause for the sterility in M₁.There is no significant difference between NMU and EMS as to both the spectra of chlorophyll-deficient mutants and the ratios of chlorophyll to viable mutations (erectoides andeceriferum scored only). The spectrum of chlorophyll mutants in M₂ was shown to be uninfluenced by the degree of sterility of the M₁ spikes. A comparative test of M₂ seedlings in the field and the greenhouse, on the other hand, gave rise to significantly different mutation spectra. The chlorophyll-deficient sectors (stripes) in M₁ plants, which occurred after treatment with NMU were classified into three phenotypes(albina, xantha, viridis). It was demonstrated that the phenotype spectrum of the M₁ stripes corresponds to that of the chlorophyll mutants in M₂.Studies on the correlations between M₁ spike sterility and mutation frequencies in M₂ indicated clearly that a selection for fertility or sterility, resp., in M₁ following treatment with NMU or EMS is highly effective. Decreasing fertility is accompanied by increasing mutation frequencies, and vice versa.The quantitative relationships between the M₁ and M₂ criteria were studied and discussed in detail. The correlations between seedling height and survival in M₁ were similar for NMU, EMS, and X-rays. For all other relations significant differences were evident between X-rays and the chemicals. Significant differences between NMU and EMS were observed as to the relations between the frequencies of chromosomal aberrations evaluated in the first mitotic cycle of germination and the other criteria. Differences between NMU and EMS also exist with regard to the toxicity of their products of hydrolysis. Long-living, radiomimetically active, or toxic products of hydrolysis could not be found for NMU.The results suggest that NMU is a suitable agent in mutation experiments for breeding or other applied purposes and gives certain advantage over the so far widely used EMS.

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N--N- , ¶rt;

N--N-o () (). , , , G₁. , 80 . , , , ₁ . , , ₁. , . ( erectoides eceriferum) Z . (albina, xantha, viridis), ₁-, , ₂. . ₁ . ₂-, . , ₁ , , , , . _{1 2}. ₁ , . . . . , , , . , N--N , , .

     

Die Aufnahme und Verlagerung des Phosphorsäurediäthylesters im Vergleich zum Orthophosphat

Uptake and Translocation of Diethyl Phosphoric acid Ester in Comparison to the Orthophosphate. . The uptake of the diethyl phosphoric acid ester (DEP) through intact adventive roots of maize plants and its further translocation to the shoots was studied over a wide range of concentrations (0.001–50.0 mM P/L) in comparison to the orthophosphate (MP). The effect of the relative humidity (r.h.) and the metabolic inhibitor Na N₃ on both processes, uptake and translocation, was also investigated. At low concentrations the plants tended to retain a greater part of the MP intaked in the absorbing roots. Depression of the transpiration streaming influenced relatively the phosphate translocation to the shoots. The higher the MP-outside-concentration was, the greater the effect of the transpiration streaming was on its translocation. Treatment with 10^-4 MNaN₃ inhibited MP-accumulation but not its translocation from the treated roots. The results showed that passive processes are mainly responsible for the DEP-uptake and translocation by the maize plants. Both processes were dependent to a great extent on the transpiration streaming. The r.h. affected the translocation patterns of both DEP and MP dissimilarly at low concentration, though, they come close to each other when their outside concentrations were increased. The results are discussed on the basis of the symplasm theory (2) and the dual mechanisms of ion uptake (28).