Abbau und Umwandlung von Pflanzenrückständen und ihren Inhaltsstoffen durch die Mikroflora des Bodens

Degradation and transformation of plant residues and their components by the microflora of the soil This review describes recent results of publications in this area. It condsiders the dynamics of degradation under field and laboratory conditions and indicates some of the problems of simulation models. The preponderant part of transformation processes apparently takes place in a relatively small fraction of soil organic matter which also includes the biomass. Methods for the quantitative measurements of the biomass have been considerably improved. The turnover rates of plant residues are effectively influenced by their chemical composition, for instance by their C/N ratio and their content of lignin or polysaccharides. C/N ratios also seem to influence the socalled priming effect and the transformation of increasing amounts of plant residues added to the soil. Some progress has been also made in the transformation of plant, residues under different climatic conditions. Experiments with polysaccharides and glucose have indicated that a major portion of the residual carbon residues in soil are contained in the biomass or N-containing microbial metabolites. A small part is also present in the phenolic constituents of humic compounds. Root excretions also contribute carbohydrates. Recent experiments indicated the transportation of a considerable amount of photosynthetic products from sprouts through roots into the soil. They cause intensive microbial turnover processes in the root zone. N-containing compounds are stabilized in the soil biomass. Proteins and aminopolysaccharides are furthermore stabilized by sorption on humic compounds or clay particles. They are even more effectively stabilized by linkage into humic compounds. Plant residues contain appreciable amounts of free and polymerized phenols which are degraded by microorganisms or incorporated into humic compounds. Easily oxidisable phenols are more slowly degraded in soil than the more stable ones. This is especially true for low concentrations of phenols added to the soil. The pH-values of the soil and its content of humic compounds influence essentially the degradation rate. Lignins belong to the most important natural biopolymers. Methods for their specific labelling with 14°C have essentially promoted studies about their degradation and transformation in soil and have enlarged the knowledge about lignin degrading organisms. Beside lignins and other plant polyphenols, melanins may play an important role in the formation of humic compounds. These melanins are synthesized form carbohydrates by some microscopic fungi through secondary metabolic reactions. They are formed from phenols, quinones, polyenes, aminoacid and aminosugar derivatives. Similar to humic acids they are relatively stabile against rapid microbial degradation. Analytical methods developed in the last years indicate that both groups of polymers contain similar building blocks.     

Einige chemische Aspekte bei der hydrolytischen Zersetzung von Harnstoff-Formaldehyd-Kondensaten mit Düngewirkung

Some chemical Aspects of hydrolytic Decomposition of Urea-Formaldehyde condensates with fertilizing Effect Model investigations have been made on the hydrolysis of urea-formaldehyde condensates with properties of slowly effective fertilizers. The properties of common urea-form have been compared with those of ureaform preparations enriched with the trace elements cobalt and copper. Data show that with hydrolysis all polycondensates' links are being attacked as depending on the medium pH and amide compounds with shorter chains are being predominantly obtained. Urea is a part of them.     

Verteilung von grenzabständen auf bodenkarten und ermittlung von risikofunktionen

Distributions of boundary spacings were analysed for different soil maps (1:25000, 1:5000) by a statistical procedure. The distributions of boundary spacings are satisfactorily described by negative exponential functions. Therefore, connections between mean boundary spacings, sampling interval and the risk of missing boundaries can be evaluated, and it is shown, that the connection between sampling interval and risk of missing boundaries is landscape specific.This results can be used for planning soil survey, particularly for special survey activities.     

Computergestützter Schätzrahmen zur Ermittlung und Verminderung von Ammoniakemissionen nach Flüssigmistausbringung

Computerized simulation framework for evaluation and reduction of ammonia emissions after liquid manure application A computerized framework for estimation of ammonia emissions after application of liquid manure has been developed. For that, the significance of the factors dry matter content, net-irradiation, surface properties, kind of liquid manure (animal species), pH-value, application techniques and rates, and precipitation on the amount and time course of ammonia emissions were determined empirically. The Windows-framework estimates the amount of ammonia emissions after liquid manure application as well as allows to calculate the effectiveness of means of reducing emissions. Therefore, the framework is a valuable tool for agricultural practice to reduce ammonia emissions.     

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.     

Ermittlung der Gesamtsäuredeposition in nordrheinwestfälischen Fichten- und Buchenbeständen

Measurement of total acid deposition into spruce and beech forests in Northrhine-Westfalia During one year the deposition of H⁺, NH₄⁺, Al³⁺, Fe³⁺ and the acidity (BNC_8,2) in bulk precipitation and throughfall of spruce and beech stands was measured in Northrhine-Westfalia. It is shown that the calculation of acid deposition as the sum of the H⁺-equivalents of (H⁺ + NH₄⁺ + Al³⁺ + Fe³⁺ + Mn²⁺) underestimates total deposition of acidity. A simple and useful alternative is the calculation of H⁺-equivalents from (BNC_8,2 + 0.9 NH₄⁺ + Mn²⁺).     

Die Oberflächenladung der Ton-Humusfraktion aus Schwarzerden als Funktion von pH und Ca-Konzentration

Surface charge of clay-humus fractions from Chernozems as a function of pH and Ca-concentration The charge characteristics of clay-humus fractions from A-horizons of several Chernozems as a function of Ca concentration and pH of the soil solution was investigated. The surface charge was measured by titration with charge compensating polyelectrolytes; the endpoint was at zero potential. A logarithmic dependence of the surface charge [mol_c/kg] on the Ca concentration of the soil solution in the range ? 2 mmol/L was observed. The influence of pH on the surface charge was almost linear over a wide range of pH-values, the change in pH-dependent charges being most pronounced for the horizons with low Ca saturation on the exchange sites. It was also found that the competition between protons and Ca ions for the exchange sites leads to a distinct decrease of the influence of Ca concentration on the surface charge in acid environment. The reason for slaking of the soil surface and of the displacement of clay-humus particles in Chernozems could be attributed to an increase in surface charge with decreasing Ca concentrations after leaching of lime. According to the present findings the drop in mobility of the clay-humus fractions during acidification could be explained by a charge compensating effect of protons and aluminium ions.     

Stickstoffernährung und Al-Toxizität bei Buchenjungpflanzen. I: Entwicklung von Buchenjungpflanzen in Abhängigkeit von der Form der Stickstoffernährung und dem Aluminiumgehalt der Nährlösung

Nitrogen nutrition and Al toxicity with young beech plants. I: Development of young beech plants in relation to the source of nitrogen and the Al content of the nutrient solution Young beech plants were grown in aerated nutrient solutions with different Al concentrations over a period of 14 weeks. Nitrogen was supplied in either NO₃- or NH₄-form. pH-changes of the solutions were either corrected to the initial pH of 4 after two days, or not corrected over a period of two weeks. Root growth of the beech seedlings was inhibited by Al. Reduction of root length and dry matter production was more severe if the plants were fed with ammonium nitrogen compared to nitrate nitrogen. Detrimental effect of Al on root growth was also influenced by the pH of the solution. NH₄-N-nutrition led to pH decrease and therefore to increased solubility and toxicity of aluminium. On the contrary, NO₃-N-nutrition weakened Al toxicity because of pH increase at the root surface and in the AFS. This led to an inactivation of Al in the form of insoluble hydroxy aluminium polymers. Compared to NO₃-N-nutrition NH₄-N promoted shoot growth. During 14 weeks no detrimental effect of Al on shoot growth was observed.     

Einfluß von Sorte und Phosphordüngung auf den Phosphorgehalt und die Aktivität der sauren Phosphatasen von Weizen und Gerste. — Ein Beitrag zur Diagnose der P-Versorgung von Pflanzen —

Influence of cultivar and phosphorus application on P concentration and acid phosphatase activity in wheat and barley. — A contribution to the diagnosis of P supply of plants — Acid phosphatase activity compared to total P concentration was studied as a diagnostic criterion of the phosphorus nutritional status of wheat and barley. In a field experiment with wheat cv ‘Sperber’ the influence of P level on P_ase activity and P concentration was monitored at four developmental stages. Significant correlations with grain yield were found for P_ase activity at all four stages whereas P concentration was significantly correlated with grain yield in the early stage (DC 26–27) only. Genetic variability and influence of P supply on P_ase activity and P concentration was studied at low and at high P supply with 9 wheat and 23 barley cultivars grown for 4 and 5 weeks in pot experiments. The variability of P_ase activity caused by cultivars was higher than that caused by P supply. It is, therefore, concluded that the acid phosphatase activity is not suitable as a generally applicable tool for diagnosing P supply. In comparison, total P concentration of the plants was influenced to a higher degree by P supply than by cultivars. Total P is, therefore, more suitable as a criterion for diagnosing P supply of plants than P_ase activity. The samples, though, have to be collected in stages before DC 27.     

Beziehung zwischen dem Stickstoff-Entzug der Pflanzen und der Abnahme von spezifisch gebundenem NH4-N im Boden

Relationship between the N uptake of plants and the mobilization of nonexchangeable NH₄-N In a pot experiment with ryegrass (Lolium multiflorum) the relationship between the release of nonexchangeable NH₄⁺ and the N uptake of plants was studied. For this purpose the surface soil of an alluvial soil and of a grey brown podsolic soil was labelled with ¹⁵NH₄-N. The following results were obtained: After treating the soil with 15-N the alluvial soil contained 4,55 mg and the grey brown podsolic soil 1,64 mg nonexchangeable ¹⁵NH₄-N/100 g soil. In the alluvial soil 72% and in the grey brown podsolic soil 66% of the nonexchangeable ¹⁵NH₄⁺ had been released during the growing season when ryegrass was planted. However, without plants there was no change in the content of labelled nonexchangeable NH₄⁺ in the alluvial soil or only a slight decrease in the grey brown podsolic soil. A highly significant correlation was found between the ¹⁵NH₄-N released and the ¹⁵N uptake of ryegrass in the alluvial soil (r = 0,78⁺⁺⁺) as well as in the grey brown podsolic soil (r = 0,98⁺⁺⁺).     

Testung und Vergleich verschiedener Methoden zur Beurteilung des N-Ernährungszustandes von Winterweizenbeständen

Test and comparison of different nitrogen status indicators of winter wheat crops Six methods of N diagnosis were tested and compared regarding practicability and accuracy of predicted fertilizer requirements in three years of winter wheat experiments at Bernburg Chernozem site. Plant analysis for total N in shoot dry matter as well as the quick tests for nitrate in the stem (with diphenylamino sulphuric acid and with indicator strips, respectively) partly indicated considerable N demand and gave recommendations for fertilizer doses, which were not transformed into grain yield during the dry weather conditions of the experimental years. Besides, the comparison of both quick tests showed unsatisfactory agreement. Values from the test with indicator strips were less accurate. The reflectance (at 550 nm wave length) of detached youngest leaves was correlated with N content in the shoot dry matter. Visual evaluation of leaves, using colour charts, did not give the expected results. In field measurements of crop reflectance the near infrared waveband and the calculated “Ratio Vegetation Index” showed to be particularly sensitive.     

Schätzung der nutzbaren Feldkapazität und Luftkapazität von anthropogenen Bodenhorizonten aus einfach zu bestimmenden Kennwerten

Estimating soil water and air capacity from physical properties in anthropogenic substrate horizons Up to now there is no appropriate method available to estimate soil water and air capacity in anthropogenic substrate horizons. The “Bodenkundliche Kartieranleitung” (German soil classification key) was developed for natural soils and can be applied to anthropogenic soils only with limited validity. For developing an estimation system, a data base of 197 anthropogenic substrate horizons was established, consisting of soil characterizations gained from own investigations and from literature. By using multiple linear regression analysis, estimating models were developed to calculate soil water and air capacity derived from values of soil bulk density, texture, amount of skeleton and content of organic matter. Though every regression model proved to be highly significant, some gained coefficients of determination less than 50%. Absolute mean standard errors of estimate vary between 3.4 and 9.1 Vol%.     

Isolierung von Solasodin-glykosiden aus Pflanzen der GattungSolanum L.Solanum-Alkaloide. XXVIII. Mitteilung

Zusammenfassung Über die alkaloidchemische Untersuchung von 68Solanum-Arten der UntergattungenArchaeosolanum Bitt. undLeptostemonum (Dun.) Bitt. sowie der SektionMorella (Dun.) Bitt. (UntergattungEusolanum Bitt.) wird ausführlich berichtet. Aus 40 Arten konnten Solasodin-glykoside (Solasonin, Solamargin,-Solamargin bzw. -Solanigrin) isoliert werden (Tabelle 1), so daß in Verbindung mit weiteren Literaturbefunden (Tabelle 2) nunmehr 67 solasodinführende Pflanzen bekannt sind.

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Summary A report of the chemical examination of 68Solanum species for alkaloids is given. These species belong to the subgeneraArchaeosolanum Bitt. andLeptostemonum (Dun.) Bitt., as well as to the sectionMorella (Dun.) Bitt. of the subgenusEusolanum Bitt. From 40 species solasodine glycosides (solasonine, solamargine,-solamargine, -solanigrine) have been isolated (table 1). Together with the earlier literature (table 2) 67 solasodine containing plants are known up-to-date.

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68 Solanum, Archaeosolanum Bitt.,Leptostemonum (Dun.) Bitt. Eusolanum Bitt. Morella (Dun.) Bitt. 40 : , ,- - (. 1). (. 2) , 67 , .

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XXVII. Mitteilung: Schreiber, K., Kulturpflanze11, 422–450 (1963), voranstehend.

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Auszug aus der Habilitationsschrift von K. Schreiber, Univ. Jena 1961; vorläufige Mitteilungen: Schreiber (1956, 1957a und 1958a), Schreiber und Mitarb. (1961).     

Schwermetall- und Nährelementgehalte von Pflanzen und Bodenproben schwermetallhaltiger Halden im Raum Bleiberg in Kärnten (Österreich) I. krautige Pflanzen

Heavy metal- and nutrient contents of plants and soil samples from metal liferous waste dumps in Bleiberg (Carinthia, Austria). I. herbaceous plants Lead and zinc concentration in the fine fraction (< 0,2 mm) of mine dump material were twice as high as in coarser fraction (2–0,2 mm) (table 1). Due to high metal levels in roots of several mine dump plants (table 3) interactions between plants and soil-microorganisms are assumed. Furthermore root originating exsudates (organic acids) are probably responsible for an increase in heavy metal availability in soil in spite of a general high pH of soil solution. The low mobility of lead within intact plants is caused by a selective affinity of this metal to cell wall pectines. On the other hand a physiological barrier (endodermis/pericycel) in primary roots of these plants is assumed, which partly prevents lead from upward transport into the shoots. Heavy metal compartmentation may be part of a tolerance mechanism diminishing a surplus of toxic metals within plant metabolism.     

Aufnahme und Verlagerung von 42K und 86Rb bei jungen Gerstenpflanzen in Abhängigkeit von einer Calcium-Behandlung der Wurzeln

Uptake and translocation of ⁴² and ⁸⁶Rb by young seedlings in relation to different calcium levels in the root medium The uptake of ⁴²K and ⁸⁶Rb by 8-d.-old barley seedlings was studied after 4 h period in solutions containing either ⁴²K or ⁸⁶Rb (1 mmol ⁴²KNO₃ + 1 mmol KCl; 1 mmol ⁸⁶RbCl + 1 mmol RbNO₃). The amount of ⁴²K was 56% and 20% higher than that of ⁸⁶Rb in the roots and shoots respectively (Pict. 1). Increasing the level of Ca in the root medium enhanced ^{42 86}Rb uptake. However the translocation rate of ⁸⁶Rb in the shoot was relatively lower than that of ⁴²K. In view of the content in the roots both elements were translocated to the shoot in a similar percentage (Table 1).     

Aufnahme und Verlagerung von 15N-Stickstoff bei Sommergerste in Abhängigkeit von K-Ernährung und Mehltaubefall

¹⁵N uptake and distribution by spring barley in relation to K nutrition and mildew attack Barley cv. Aramir was grown in complete nutrient solution containing 0,5 (K₁), 1,5 (K₂) and 4,5 mM K (K₃) respectively till maturity. Part of the plants was infected by mildew (Erysiphe graminis), whereas control treatments were kept mildew-free by fungicide sprays. Symptoms of mildew attack were less at K₂ and K₃ and grain yields of infected plants were raised from 98 (K₁) to 160 (K₂) and 165 g/pot (K₃). In control treatments grain yields were 130 (K₁), 164 (K₂) and 163 (K₃) g/pot. During anthesis nitrogen in the nutrient solution was labelled with ¹⁵N for two days and ¹⁵N metablism was studied within 7 consecutive days. The aim of this pulse-chase experiment was to find out, how mildew attack and K nutrition influence N metabolism. The following results were obtained: a) ¹⁵N uptake increased from K₁ to K₂ in infected and healthy plants, though at slightly lower levels in the infected treatments. b) During 7 days after the ¹⁵N pulse up to 17,1% of the ¹⁵N absorbed were translocated into the grains. Better K status as well as spray treatments stimulated nitrogen translocation. c) Mildew attack of leaves does not seem to influence the conversion of grain-¹⁵N into grain proteins. Better K supply stimulates the rate of protein synthesis in the grain. d) In mildew infected leaves relatively more of the ¹⁵N absorbed is incorporated into leaf proteins. But this may be a consequence of slower grain growth, because already 7 days after anthesis infected plants in all K treatments had significantly lower grain yield. In spite of the short duration of the experiment the ¹⁵N data do not indicate that the visible depression of mildew attack by better K nutrition of the crop might inter alia be due to K stimulated defense reactions within N metabolism. This is in agreement with a previous experiment.