Kurzmitteilung Bestimmung von Dicyandiamid,Nitrit und Nitrat in Bodenextrakten mit Hochdruckflüssigkeitschromatographie

Determination of dicyandiamide, nitrite and nitrate in soil extracts by high pressure liquid chromatography A method for simultaneous determination of dicyandiamide, nitrite and nitrate in soil extracts and percolation water by means of HPLC has been developed. Extraction is done with water or CaCl₂, followed by separation on a RP–C18 column with tetrabutylammonium hydrogen sulfate and sodium dihydrogen phosphate as mobile phase UV-absorbance is measured at 220 nm. Detection limit is 0.1 mg N/I.     

Gehalte an Haupt- und Nebenelementen in Konkretionen aus Oberböden von Marschen – Untersuchungen mit einer Mikrosonde

Contents of major and trace elements in concretions of surface samples from marsh soils – Electron microprobe analysis The amounts of 14 elements (Ti, Fe, Mn, Si, Al, Ca, and P, S, Co, Ni, Cu, Zn, Cd, Pb) in concretions of four A horizons of marsh soils were determined by electron microprobe analysis on thin sections. According to the major element compositions the following types of concretions can be distinguished: Ti-Fe(-Mn) concretions (31–39% Ti; 18–29% Fe; 0,3–5,5% Mn); Fe(-Mn) concretions (31–58% Fe; ≤ 1,8% Mn); Fe-Si(-Mn) concretions (6–28% Fe; 8–42% Si; ≤ 5% Mn); Mn-Fe and Mn-Fe-Si concretions (16–40% Mn; 2–9% Fe; 2–15% Si). The formation of Ti-Fe(-Mn) concretions can be explained by adsorption of Fe²⁺ ions under reducing conditions on surfaces of Ti minerals followed by oxidation to Fe(III) oxide. In this way pseudorutile may be formed. Concretions with high Fe and/or Mn content often contain occlusions of carbonates, silicates and/or SiO₂ (bioopal) which may act as nuclei for their growth. Redox processes in marsh soils result in the formation of concretions with dominating Fe or Mn accumulation. Among the group of trace elements, P and S (like Ti and Si) reach their highest concentrations in Fe rich concretions (up to 54.000 mg P/kg and 4.200 mg S/kg). The accumulation of these elements is obviously influenced by anion competition, especially of P and Si, and probably also Ti. Likewise, high amounts of Pb were found in Fe(-Mn) concretions (up to 12.000 mg/kg). Co, Ni, Zn, and Cd show the highest amounts in Mn rich concretions (Co up to 3.400; Ni 1.800; Zn 13.200; Cd 1.000 mg/kg). Cu is also accumulated in some concretions (up to 1140 mg/kg) but no clear affinity to one of the different types of concretions was found.     

Die Validierung von Bodenwasserhaushaltsmodellen mit Hilfe von TRIME-TDR,Tensiometermessungen sowie thermogravimetrischen Bodenfeuchtebestimmungen

The validation of soil water balance models based on measurements of soil water contents by gravimetry and by TRIME-TDR and of soil water suctions determined by tensiometer In this study different measuring techniques for determining soil water contents and soil water suctions were analysed for their suitability for the validation of soil water balance models. For this purpose a period of three years with continuous data of soil water contents measured by TRIME-TDR and soil water suction measured by tensiometer were available. Additionally soil samples at different times were taken for gravimetric moisture analyses. These measurements were compared with the corresponding simulation results of a soil water balance model. This soil water balance model consists of the determination of evapotranspiration according to Penman-Monteith and the calculation of soil water fluxes based on the Darcy-equation. The results indicate the higher suitability of TDR-measurements for evaluating the goodness of fit between the simulated and the calculated results in comparison with the other measuring techniques used in this study, especially in the context of general soil water dynamics. The tensiometer data show the limited measuring range as a well known disadvantage of this technique.     

Einfluß von Lagerungsdichte,Ton- und Schluff- sowie Humusgehalt auf die Wassergehaltsbestimmung mit Neutronensonden

Influences of soil density, clay, silt- and humus content on measurements of soil-water by neutron gauges .     

Untersuchungen zur Anpassung des Stickstoff-Angebots aus unterschiedlichen N-Quellen an den Verlauf der N-Aufnahme von Maisbeständen

Investigations on the adjustment of nitrogen supply from different N sources to the N uptake of maize A two years field experiment was conducted to study the effects of the nitrogen fertilizers: wheat swill, BASAMMON (NH₄ + nitrification inhibitor DCD) and calcium ammonium nitrate (CAN) applied at N rates of 0.60.120 or 180 kg N/ha on yield, N uptake and soil mineral N residues of maize for silage or grain production. CAN was either broadcast or placed in the maize rows, with or without the addition of an Azospirillum-biopreparation (AZOGREEN). Due to initially high soil mineral N contents (50–70 kg N/ha) and a high mineralization from the soil (unfertilized: 100–170 kg N/ha), neither effects of fertilizer type, nor interactions between fertilizer type and N rate on biomass production and N uptake of maize were observed. The economically optimum total dry matter production and grain yield were obtained with a fertilization of 60–120 kg N/ha. In contrast to the biomass production the soil mineral N was considerably influenced by fertilizer type and N rate. The nitrate content of the soil increased during the early developmental stages of maize after an early application of swill or BASAMMON, and also during the ripening period after a late high dose of CAN. Though the placement of CAN was reflected in the soil, the soil nitrogen content per unit area could not be much reduced by row fertilization. The effects of AZOGREEN were only small. The results were greatly influenced by the high mineralization potential at the experimental site.     

Untersuchungen zur Zusammensetzung der Blattpigmente an Mutanten vonLycopersicon esculentum,Lycopersicon pimpinellifolium und Antirrhinum majus

Zusammenfassung Die Mutantensortimente vonLycopersicon esculentum, Lycopersicon pimpinellifolium undAntirrhinum majus des Zentralinstitutes für Genetik und Kulturpflanzenforschung wurden einem Screening-Programm zum Auffinden von Formen mit von der Norm abweichender Zusammensetzung der Photosynthesepigmente unterzogen. Dazu wurden zunächst die Absorptions- und Derivativspektren der Blätter sämtlicher Mutanten in vivo gemessen. Nach Auswertung dieser Spektren wurden verschiedene Mutanten mit veränderten Pigmentverhältnissen ausgewählt, an denen zusätzlich eine Chlorophyllanalyse im Azetonextrakt durchgeführt wurde.Auf diese Weise wurden Mutanten mit teilweise stark veränderten Chlorophyll a/Chlorophyll b-Verhältnissen gefunden.Anhand dieser Ergebnisse wurde geprüft, inwieweit eine quantitative Bestimmung der Chlorophylle aus dem in-vivo-Spektrum möglich ist.Die erhaltenen Ergebnisse zeigen weiterhin, daß Pflanzen mit verringertem Chlorophyll b-Gehalt einen höheren Anteil an der kurzwelligen Chlorophyll a-Form in vivo (C_a673) besitzen.

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On the composition of leaf pigments in mutants ofLycopersicon esculentum, Lycopersicon pimpinellifolium andAntirrhinum majus

Summary The mutant collections ofLycopersicon esculentum, Lycopersicon pimpinellifolium andAntirrhinum majus of the Zentralinstitut für Genetik und Kulturpflanzenforschung were investigated in order to find mutants with changed composition of the photosynthetic pigments.For this purpose the absorption and (second) derivative spectra of the leaves of all mutants were measured. After evaluation of these spectra some mutants were selected, which were additionally analysed by extracting the leaf pigments in acetone.In this way some mutants with strongly changed chlorophyll a/chlorophyll b ratios were found.Proceeding from these results the possibility of a quantitative estimation of the chlorophylls from in vivo spectra was tested.Furthermore it was shown, that plants with a decreased content of chlorophyll b have a higher amount of the short wave form of chlorophyll a (C_a673) in vivo.

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Lycopersicon esculentum, L. pimpinellifolium Antirrhinum majus

, »« . ¶rt; , , in vivo . , , , . . , in vivo. , in vivo (C_a673).

     

Wachstum und Ernährung von Eberesche,Buche und Fichte im Gefäßversuch mit immissionsbelasteten Bodensubstraten aus dem Erzgebirge

Influence of simulated sulphur and nitrogen depositions on biomass and nutrient relationships of mountain ash, European beech and Norway spruce in a pot experiment with two soil substrates from the Ore Mountains Growth and nutrient relationships of mountain ash (Sorbus aucuparia), European beech (Fagus sylvatica) and Norway spruce (Picea abies) were investigated in a pot experiment with the two substrates rhyolithe (acidic) and basalt (alkaline). Additionally, depositions of sulphur (S) and nitrogen (N) as expected to occur in the Ore Mountains (Saxonia, Germany) in the future were simulated in order to test the species′ suitability for forest regeneration. After two years, aboveground biomass was significantly higher on basalt compared to rhyolithe for all species. The amount of S given (0 and 100 kg ha^—1 a^—1) and the dominant form of N applied (NH₄⁺:NO₃^— = 1:4 and 4:1; total amount of N given 80 kg ha^—1 a^—1) were of minor influence only. The contents of N and K in leaves or needles were higher on rhyolithe, whereas P, Ca, Mg and Mn contents were higher on basalt. Nutrient contents were only slightly affected by the amount of S supply and the NH₄⁺:NO₃^— ratio. In contrast to mountain ash, beech saplings exhibited considerable growth on rhyolite. It is therefore concluded that beech may be a suitable species for forest regeneration even on acidic soils suffering heavily from S and N immissions, whereas spruce will not tolerate high S loads. However, increasing N depositions by stimulating growth may cause deficiencies of Mg and K in both species.     

Mikrosondenuntersuchungen an unterschiedlich stark mit Schwermetallen belasteten Böden. 2. Gehalte an Schwermetallen und anderen Elementen in Huminstoffaggregationen,Streustoffen und Holzkohlepartikeln

Electron microprobe studies on soil samples with varying heavy metal contamination. 2. Contents of heavy metals and other elements in aggregations of humic substances, litter residues and charcoal particles EMA point analysis show that the organic matter constituents of heavy metal contaminated soils are highly enriched with heavy metals. The maximal trace element accumulation were for Cu up to 13,000 mg/kg, for Zn up to 48,000 mg/kg, for Cd up to 2,100 mg/kg and for Pb up to 193,000 mg/kg. The affinity for the accumulation of the different heavy metals in aggregations of humic substances can be described by the sequence Cu > Pb ? Cd > Zn ? Ni > Co. In very strongly acidified humic top soil horizons the Pb and Cd accumulation in the organic matter constituents is in competition with the accumulation in Fe and Mn oxides. The heavy metal contents (especially of Cu) of the organic matter are often correlated with the content of organically bound calcium. The EMA results also show that high heavy metal amounts occur in combination with Ca-accumulations in the epidermis and the outer bark parenchym of decayed roots. EMA point analysis of the interior of fungus sclerotias show that sclerotias can contain high amounts of heavy metals, in particular lead (up to 49,700 mg Pb/kg). From statistical results of EMA point analysis follows that lead and other heavy metals attached to humic substances are not only bound as metal organic complexes but also as organic metal phosphate complexes. Also charcoal particles of polluted soils contain high amounts of heay metals. The accumulation affinity is quite similar to that of humic substances.     

Die Ermittlung der Porengrößenverteilung aus der Körnung,dem Gehalt an organischer Substanz und der Lagerungsdichte

The estimation of pore size distribution from texture, organic matter content and bulk density Using regression analysis the dependence of the pore size distribution of soils on the compactness and percentage of organic matter, clay and silt was studied on 450 soil horizons. From the results nomograms for determination of the pore size distribution were constructed. The average deviation between pore size distribution as read from the nomograms compared and determined in the laboratory is ～ ± 3 Vol.-%.