Vertikaler Wasser- und Nitrattransport in tiefere Bodenschichten süddeutscher Ackerstandorte

Vertical water and nitrate movement into deeper soil layers on fields located in the south of Germany In Southern Bavaria, selected fields from deep loess and sandy sediments were sampled to a depth of maximum 10 m every 4 months, in order to determine the basic processes of water and nitrate movement in the course of the year. The downward movement of water and nitrate followed the principle of piston flow only in the intermediate vadose zone of loess soils with a leaching distance amounting 0.8 m per year. On the other hand, an accelerated as well as a delayed transport was observed in the zone of evapotranspiration of loess soils and in the whole profile of sandy soils, not being in accordance with the simple simulation model FLOTRA based on the classic theories of transport (Darcy flow, convection-dispersion-equation). Preferential flow led to the leaching of nitrate from the top soil to the lower boundary of the evapotranspiration zone of loess soils in 2 m depth, in winter and spring. In sandy soils nitrate was leached to the groundwater table in 4–6 m depth after extensive rainfall.     

Zur Pedogenese und Klassifikation von Marschböden des Unterweserraumes. II. Die Bedeutung von Schwefelmetabolismus,Methanproduktion und Ca/Mg-Verhältnis für die Marschen-Klassifikation

Development and Classification of Marsh Soils from the Unterweser Region, West Germany. II. Importance of Sulfur Metabolism, Methane Production and Ca/Mg Ratio for Classifying Marsh Soils The importance of sulfur metabolism in each step of marsh soil development (Brümmer, 1968) is also confirmed for the marsh soils of the Unterweser region. Sulfur contents and sulfur fractions indicate that soil development has advanced further in brackish marshes than in marine and river marshes. The results give additional evidence that the various properties of marsh soils are only partly caused by sedimentation conditions. – The sedimentation areas (Müller, 1954) apply only to small regions. Thus, methane production predominates in the freshwater area, while sulfate reduction predominates in the marine area. Both processes occur at high rates in the brackish area. Classifying soils on the basis of the Ca/Mg ratio gives the same soil groups as Brümmers classification. Consequently, classifying the marsh soils of Niedersachsen on the basis of Ca/Mg ratio is a suitable method, if the idea that sedimentation conditions cause soil properties – especially the contents of exchangeable Ca and Mg – and the present designations of the soil groups are rejected.     

Untersuchungen zur Bedeutung des Ernährungszustandes von Kulturpflanzen für ihre Salztoleranz

Investigations on the significance of the nutritional status of plants for their salt tolerance In order to explain the causes of salt damages on crops in the Sibari Plain (Southern Italy) the nutrient contents of plants were used in addition to soil data. Increasing Na- and Mg-salinity reduced the K-contents of wheat plants during sprouting below the (preliminary) critical value of 30%_o and the Ca-contents below the value of 3%_o in spite of high gypsum contents and optimum K-supply of the soils (compared to soils with low salt contents). The content of nutrient elements can be improved by an increased nutrient supply up to the optimum range, and the content of detrimental elements in plants can be reduced below toxic limits. The specific toxicity of Mg-salts (believed to be especially high) could be prevented by optimum nutrition of the plants until general salt effects became dominant factors of damage. At optimum nutrient supply 6–7%_o Mg in the tops of corn plants were toxic in greenhouse experiments. In the field even at high Mg-supply of the soils no more than 2,5%_o Mg were found in cereals. At optimum K-supply more than 1–2%_o Na in wheat plants reduced the yield. The salt tolerance of plants, therefore, can be increased by proper fertilisation.     

Stickstoff-Assimilation in der Wurzel und Transport von N-Verbindungen mit dem Blutungssaft der Wurzeln in Abhängigkeit von der Mn-Versorgung

Nitrogen Assimilation in Roots and the Transport of Nitrogen Compounds in the Bleeding Sap of Roots in relation to Manganese Nutrition. The assimilation of nitrogen in the roots of 27 days old pumpkin plants was examined in relation to manganese nutrition. The transport of nitrogen compounds in the xylem was determined in roots and in the bleeding sap of roots using nitrate as the N-source. The maximum NO₃ content in the roots was observed in the Mn treatment which resulted in the highest shoot yields (0.05 ppm Mn). The bleeding sap of this treatment was lowest in nitrate concentration, but showed the highest rate of transport of organic nitrogen compounds. In experiments with ¹⁵N in the nutrient solution the isotope was found in the roots in organic and in inorganic compounds. The composition of the fraction of free amino acids differed between roots and xylem sap. In the bleeding sap glutamine was especially dominant. In the roots the amino acid composition depended on the extent of Mn-supply. Lowest glutamine concentrations were found in the xylem sap from the treatment with maximum shoot yields. A numerical difference was found in the xylem sap between organic N (N_(org)) and the amino acid nitrogen. This difference which account for more than 50 % of the organically bound nitrogen is suggested to be made up in part by low molecular weight peptides, amino sugars and other compounds. In Mn deficiency a general reduction in the intensity of nitrogen metabolism was found. With Mn toxicity the N assimilation activity was more intensive than for the low Mn supply. Simultaneously, however, the transport of organic N compounds from the root was lower.     

Untersuchungen zur physiologischen Bedeutung von Chlorophyllb,eine Literaturübersicht

Значение хлорофилла Ъ обсуждается в литер атуре со следующих точек зрен ия:

1. Улучшение абсорбции света зелеными расте ниями.
2. Полимеризация фотос интетически возникш их моносахаридов до кра хмала.
3. Стабилизация фотоси нтетического аппара та.
4. Первичная фотосинте тическая реакция как таковая.
5. Накопление и перенос энергии на фотосинте тически действующие молекул ы хлорофилла a.

     

Untersuchungen zur Kohlenstoffdynamik und Bioturbation von Mollisolen

Investigations regarding carbon dynamics and bioturbation in Mollisols Bioturbation in Mollisols (mollic horizons) is not really leading to a homogenisation of C-atoms of different ¹⁴C-ages. Age versus depth curves indicate rather flatly stretched or steeper shapes, dependent on either slow development via an extended pararendzina phase or faster growth of the mollic epipedon under more half bog like conditions. 291 ¹⁴C-dates of Mollisols versus depth of soil result in one mutual and several individualized regression lines for the countries of origin with variable coefficients of X. Highest levels of X indicate steepest increase of age towards depth, i.e. weakest bioturbation in the sense of homogenization. When eliminating 16 sand covered Mollisol samples from Tunisia 275 dates remain, which, plotted as age/profile maximum age versus depth, produce regressions of the date collectives of different countries in relation to organic matter decomposition. The steepest regression line indicates maximization of old carbon species and most intensive decomposition of the young organic matter; the flat ones stand for slowed down decomposition. Comparative ¹⁴C-dates of texture fractions of the aquic Hapludolls ?Asel”? and ?Söllingen”? show age maxima in the middle clay and fine clay fractions. ¹⁴C-dating of the body – C of layerwise collected earthworms as well as of fillings of fossil rainworm or Citellus tracks reveal for the worm – C exclusively recent bomb – C (> 100% NBS) with youngest C species in the top soil and in the greatest depth of the soil profile. The fossil rainworm and Citellus track-fillings are above the measured total soil age. Studies of the decomposition of organic matter from different soil depth indicate in case of the almost neutral agricultural soil ?Söllingen”? expectedly lowest CO₂-release from the organo-mineralically stabilized soil layer at maximum depth (in mgC/100 g soil as well as in mg C/g C_org). In case of the more acid forest soil ?Asel”? the same trend of diminishing CO₂ release with depth prevails at normal soil-pH as well as under condition of uniformly adjusted pH to 7.5–8.3. The two deepest layers (80–100 cm) fall of the trend by higher rates of decomposition. The unfavorable ratio of organic C (0.139%) versus carbonate-C (1.54%) under synchroneous pH-increase is considered responsible.     

Die Bedeutung der Umsetzung von Weizenstroh im Hinblick auf den C- und N-Haushalt von Löß-Ackerböden

The significance of wheat straw decomposition with regard to the C- and N-cycle of a cultivated loess soil In 1984/85, a microplot experiment with ¹⁵N-enriched fertilizer was carried out on a field of the Calenberg loess area near Hannover (surface area of the plots: 1 ± 2 m; experimental soil: stagnigleyic cambisol from loess). On the one hand, the extent of immobilization as well as remobilization of native soil- and fertilizer-N associated with straw incorporation (± 8 t/ha) was quantified. On the other hand, the turnover as well as the alteration of C- and N-masses in the decomposing straw material was studied. About 70% of the initial dry organic matter of straw was mineralized within one year. An enrichment of fertilizer-N as well as native soil-N in the residues of up to 20 kg/ha was observed as compared to the initial N-mass. On a microplot cropped with winter-wheat, microbial N-immobilization of about 30–40 kg/ha (native soil-N and fertilizer-N) occured in the soil after straw incorporation. The immobilization extended to march 1985. Subsequent, associated with a C/N-ratio in the straw of 43, N-remineralization as well as -extramineralization was observed with 40 kg/ha at maximum in december 1985.     

Zur hydrologischen Bedeutung der organischen Auflage im Wald: Untersuchungsmethoden und erste Ergebnisse

About the hydrological role of organic layers in forest: methods and first results The forest floor (total organic matter above the surface of the mineral soil) is an important interception storage for throughfall. Therefore, it must be considered in detailed water balances of forest. The objective in this paper is to present a method for measuring the forest floor percolation. It was developed within the framework of the interdisciplinary project Ecosystem research in the Bornhöved lake region. A technique for permanent registration of mineral soil input and a vacuum control system for mini lysimeters and suction plates are described. The registration system has a resolution about 0,1 mm. Some figures illustrate the instrumentation, respectively measured row data and some results. Finally, the used materials, their properties and sources of supply are presented.     

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.     

Zeitschrift für Pflanzenernährung und Bodenkunde: Schwermetallgehalt von Wurzel und Sproßorganen der Rebe (Vitis vinifera L.) nach Düngung mit Müll-Klärschlammkompost

Heavy metal content of roots and shoots of vines (Vitis vinifera L.) after fertilization with garbage-sewage-sludge-compost The enrichment of Zn, Cu, Pb, Cd, Co, Ni and Cr from garbage-sewage-sludge-compost in vineyard soils, vines and must was studied in field-and pot-experiments. The following results were obtained: 1. In a field experiment, in which garbage-sewage-sludge-compost was applied, a marked soil enrichment of Zn, Cu, Pb, Cd and Cr was found. It was most evident at the 0–20 cm depth but also obvious at the 40–60 cm depth thus indicating downward migration. The soil was not enriched with Co and Ni. The heavy metal content of leaves, berries and must of riesling vines did not increase on the plots treated with garbage-sewage-sludge-compost. 2. In a pot trial, using an acid and an alkaline soil each mixed with garbage-sewage-sludge-compost, it was observed that only the uptake of Zn and Cu increased into the leaves, tendrils and wood of the riesling cuttings. In relation to the content of the substrate, the heavy metals were detected in the roots percentually in the following order: Cu, Cd > Zn > > Pb, Co, Ni, Cr The root contents were mostly substantially higher than those of the shoot. The migration from root to shoot decreased in the following percentual order: Zn > Cu > Cd, Pb 3. The heavy metal content decreased considerably from the roots to the upper plant organs. This was reflected in low concentrations of heavy metals in the vine must.     

Veränderungen in der stofflichen Zusammensetzung von Buchenstreu und Gerstenstroh beim Abbau unter Laborbedingungen

Chemical changes of beech litter and barley straw during decomposition under laboratory conditions Beech litter and barley straw were incubated at 20°C and 70% of maximum water holding capacity in the presence and absence of artificial “soil” and earthworms (Eisenia fetida). Results show that beech litter biodegradation was enhanced by E. fetida during the first part, but delayed in later stages of the incubation period, as indicated by the changes of ash contents and C-to-N ratios with progressive decomposition. In the long run the organic matter (OM) of beech litter tended to be stabilised through the action of worms. In contrast, for barley straw a more intense biodegradation was observed in the presence of E. fetida throughout the experiment. Almost 80% of litter and straw OM could be identified by means of wet chemical degradation methods (70% polysaccharides, lignin; 10% lipids, protein). The proportion of the exclusively plant-derived constituents cellulose and lignin showed a partly strong decrease with progressive decomposition; simultaneously the contents of also microbially synthesised components such as non-cellulosic polysaccharides and protein increased. Changes of the non-cellulosic polysaccharide-cellulose-quotients (NCQ), lignin-cellulose-quotients (LCQ), and acid-to-aldehyde ratios (ac/al)_v and (ac/al)_s in the residual lignin reflected well the litter decomposition process. At the end of the experiment - irrespective of treatments - the degree of beech litter biodegradation was comparable to that of Of-Oh transitional layers in beech-derived forest humus profiles. In the case of barley straw only NCQ and LCQ, but not (ac/al)_v,s were valuable parameters for the characterisation of the decomposition process.     

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.     

Zur Kalkwirkung von Phosphatdüngemitteln

Basic effect of phosphorus fertilizers To test the basic effects of Thomas slag (Basic slag), Rhenaniaphosphate, Superphosphate, Hyperphos (soft rockphosphate) and Novaphos (partly water soluble phosphate), model, pot and longterm field trials were carried out. Changes in soil pH and base saturation served as a measure of the basic effect. The basic effect results from chemical reaction (oxides, hydroxides, carbonates and silicates of alkali- and earth alkali components as well as Ca-phosphates) and physiological reaction (different uptake of P and Ca by plant roots in exchange with HCO and H⁺). In contrast to Thomas slag and Rhenaniaphosphate the basic effect of Hyperphos due to chemical reaction is small; Superphosphate and Novaphos both have a chemically acidic reaction. Plant growth increased the basic effect of all fertilizers, especially of Hyperphos. On acid and weakly acid soils (field and pot trials), Hyperphos achieved about the half effect of Thomas slag expressed on a total phosphate basis whereas the effects of Superphosphate and Novaphos were only poor. The basic effect of P-fertilizers is directly associated with their solubility and P-effectiveness depending on particular soil conditions (pH). In a pot trial using loamy soils with a requirement for lime and small requirement for phosphorus, Thomas slag, Rhenaniaphosphate and Hyperphos showed nearly the same basic effect (50kg CaO per 100kg fertilizer). This value contrasts with the much lower figures for Novaphos (10–20kg) and Superphosphate (0–10kg).     

C. Zur Geschichte von Dorf und Burg Gatersleben

Genetic Resources and Crop Evolution -     

Bedeutung der Kalium-Verarmung in der Rhizosphäre und der Tonminerale für die Freisetzung von nichtaustauschbarem Kalium und dessen Bestimmung mit HCl

Significance of K-depletion in the rhizosphere and clay minerals for the release of nonexchangeable potassium and its determination with HCl Experiments were carried out with four different soils (basaltic soil, C-horizon of a keuper, sea alluvium, and a podsolic brown earth from loess) to investigate whether the fractions of exchangeable K and HCl-soluble nonexchangeable K are decreased in root vicinity by the K uptake of ryegrass (Lolium perenne). After a growth period of 70 days with five cuts distinct K depletion profiles were obtained showing that in the direct vicinity of the root the decrease in exchangeable K was the most pronounced. The K depletion in this fraction extended to 2 cm distance from the root zone. Also the concentration of HCl-soluble nonexchangeable K of the interlayers was decreased in root vicinity. It is assumed that the decrease in K concentration in soil solution is a prerequisite for the net release of interlayer K. The decrease in exchangeable K plus HCl soluble nonexchangeable K was equal to the amount of K taken up by the grass from the basaltic- and the alluvial soil. In the case of the podsolic brown earth and the keuper soil, however, much more K was taken up by the grass than was found in the decrease of exchangeable K plus HCl soluble nonexchangeable K. It is assumed that in these two soils the fraction of the HCl soluble K was more altered by the expansion of interlayers during the growth of rye-grass. The net release of interlayer K was neither related to the concentration of exchangeable K, HCl-soluble non-exchangeable K, the K fixation power nor the clay concentration. It is supposed that the net release of interlayer K also depends on clay mineral characteristics.     

Zum jahreszeitlichen Nitratgehalt und zur Nitratauswaschung von landwirtschaftlich genutzten Böden in Baden-Württemberg

Seasonal nitrate content in, and nitrate leaching from, agricultural soils of Baden-Wuerttemberg The behavior of soil nitrate was investigated at five field locations in the State of Baden-Wuerttemberg between 1984 and 1987. It was found that the amount of nitrate in the upper 90 cm of soil was not a constant, but fluctuated throughout the year with maxima in the spring and in the fall. Additionally, it was found that the amount of nitrate leaching during winter (from November through April) was correlated to, but not identical with the mineral nitrogen content of the previous fall. It further appeared that nitrate leaching in light sandy soils is mainly a mixing process, whereas in heavy soils it seems to be more a miscible displacement phenomenon.