Die kurzfristige pH-Pufferung von gestörten und ungestörten Waldbodenproben

Short-timed pH-buffering of disturbed and undisturbed forest soil samples The pH buffering of disturbed and undisturbed soils under spruce (podzol and podzolic cambisol derived from phyllite, eutric cambisol derived from basalt) was studied in the laboratory by adding H₂SO₄ in ecologically relevant concentrations (pH 5.6–2.0). For the cambisol with crumb structure no difference was found. 80–90% of the added protons were neutralized by release of Ca and Mg. Disturbed samples of the podzol buffer less than 70% of the applicated acid. For undisturbed samples the maximum buffering rate of 185 g H⁺/ha · h is reached with a proton load of about 500 g H⁺/ha · h (related to 4 cm soil depth). Buffering behaviour of the podzolic cambisol lies between the podzol and the cambisol. 70–90% of the proton input is buffered in the disturbed samples while the undisturbed one does not reach its maximum buffering rate, even with high proton load. In this soil Al-release is the most reactive buffer.     

Berechnung des kapillaren Aufstiegs aus dem Grundwasser in den Wurzelraum unter stationären Bedingungen

Calculation of capillary rise from groundwater table into the root zone under steady-state conditions .     

Eine Einrichtung zur Beregnung von Bodensäulen

A device for the irrigation of soil columns An irrigation device was designed for maintaining a constant water flow in soil columns over a long period of time. The apparatus consists of three construction elements: A balance for the dosage of the water, a sprinkler to distribute the water on the soil surface and an electronic time control to adjust different time steps. The wide range of possible rain intensities is shown. The mean variation of the water pulses and their distribution over the surface are discussed. The apparatus exhibits good results in long duration experiments.     

Simultane Bestimmung von N-Transformationsraten in Bodensäulen unter Verwendung von 15-N: Stickstoffmodell für eine Terra fusca-Rendzina

Simultaneous determination of nitrogen transformation rates in soil columns using 15-N: N-Model of a Terra fusca-Rendzina soil Rates of ammonification, nitrification, immobilization, and denitrification were determined in undisturbed columns of a Terra fusca Rendzina soil. A steady input of 15-N labelled ammoniumsulfate with the irrigation water created a steady state of the turnover processes in the soil resulting in a constant output of 15-N-nitrate. In this state the rate constants (8°C) were K₁ = 0.64 for the netto-N-nitrification, K₂ = 0.11 for the netto-N-denitrification, and K₃ = 0.25 for the netto-N-immobilization. 64% of the nitrate was leached, 25% immobilized in organic matter, and 11% denitrified. Relating these rate constants to the turnover of the soil nitrogen one can calculate the mean annual rates for the different processes of a forest soil, using the mean annual temperature. For the Göttinger Wald situation (T = 6.9°C) the following rates were calculated; Ammonification = 183 kg N·ha^?1·a^?1, immobilization = 44 kg N·ha^?1·a^?1, netto N-denitrification = 19 kg N·ha^?1·a^?1, and netto-N-mineralization = 120 kg N·ha^?1·a^?1.     

Ungestörte Bodensäulen: eine Methode zur Herstellung,Beregnung und Installation im Labor

Undisturbed Soil Monoliths: a Method for Preparing, Installation, and Sprinkling in the Laboratory A method for preparing undisturbed soil monoliths is described. The columns are encased with water-repellant cement. Because of the intense contact between soil and cement edge effects are prevented. On account on the cement, the pH-value in the periphery of the soil columns increase by one degree. The monoliths are sprinkled by a precipitation simulator at any adjustable intervall. Soil monoliths of this kind are suitable for testing chemicals, if the soil has to be analyzed, as well as for investigations concerning the water flow.     

Auswirkungen einer Temperaturerhöhung in einem Freilandexperiment auf den Stickstoffaustrag aus Bodensäulen mit verschiedenartiger Humusform

Effects of a temperature increase in a field experiment on the nitrogen release from soil cores with different humus forms Global warming could have far-reaching consequences for the properties of soils. From the available knowledge it is postulated that an increase in temperature (all other climatic conditions unchanged) will decrease the nitrogen contents until a new equilibrium is reached. To test this hypothesis we established in the ‘Tegernsee Alps’ a field experiment. In spruce-dominated montane forests 60 undisturbed soil cores (= monoliths) were carefully digged out at 1250 and 1320 m asl and reestablished at 3 elevations (1250 m and 1010 m and at 740 m asl) corresponding to a warming of around 1 and 2°C. At each slope position we investigated a Dystric Cambisol with raw humus (RH) and another one with moder (MO). Each of these 6 trial-variants therefore was represented by 10 monoliths. From August 1992 to December 1995 seepage water was sampled by suction cups every 2 or 4 weeks and analyzed for the concentrations of important bioelements including aluminum, pH and electrical conductivity. After translocation to warmer climates additional nitrogen was released from both soil forms mainly as nitrate. The cambisol with the more active humus form moder reacted stronger than the one with raw humus (additional output > 40 vs. 34 kg ha^?1 a^?1; +2°C). In both soil forms the N release was accelerated in summer, in RH by 55 to 92 and in MO by 37 to 86 ppm. The Cambisol with moder showed higher nitrate leaching also in winter and thus was superior with regard to the total annual N output. In all cases Al was the most important associated cation to NO₃^? with 75% (RH) and 54% (MO) of the cation equivalent sum respectively. The experiment thus confirms a substantial increase of nitrification even by a temperature increase of only 1 and 2°C, which in permeable, well aerated soils should lead to increased nitrate leaching under conditions where no vegetation is interfering.     

Extraktion eines kupferbelasteten Bodens unter Verwendung eines aminosäurehaltigen Reststoffhydrolysats. 2. Elutionsdynamik und Bilanzierung der Aminosäuren nach kontinuierlichem Eintrag in Bodensäulen

Extraction of a copper contaminated soil material by the percolation of an amino acid containing residue hydrolysate. 2. Time course of amino acid elution and input/output balance of amino acids During 16 days an amino acid containing blood meal hydrolysate (amino acid concentration: 188 mMol·L^?1) was percolated through a column packed soil material (soil content per column: 4.1 kg dry weight, four parallels). The copper contaminated material (soil type: Typic Udifluvent, soil texture: sandy loam, loamy sand) was sampled from an area formerly used for cultivation of hop (Humulus lupus). Besides the investigation of the copper liberation the experiments aimed to determine the elution dynamic and input/output balance of amino acids (time span for amino acids balance 14 days). In total 11.7 L of hydrolysate, containing 2.2 Mol of amino acids, were introduced into each column. The mean amino acid output with the column effluent was 1.13 Mol. This corresponds to an elution degree of 51.2%, related to the sum of applicated amino acids, and to a mean substance specific elution degree of 48.4% reflecting the elution of 15 compounds. The substance specific elution ranged from 9.6% (serine) to 75.5% (valine). The highest concentrations of serine and threonine were determined in the effluents after two days, whereas the histidine concentration was highest at the last sampling. The differences in the percolation properties of the amino acids are discussed in terms of important retention and elimination processes (biodegradation, ad-/desorption, intercalation).     

Schwermetalle in Oberböden des Warthetals unter städtischem Einfluß

Heavy metals in surface soils of the Warta river valley in an urban area In the urban area of the city of Poznan the contamination with heavy metals was investigated. From the top soil layers of five cross-sections of the valley of the Warta river 87 samples were collected. Beside common soil characteristics the contents of arsenic, barium, cadmium, chromium, copper, iron, lead, manganese, phosphorus and zinc were analyzed. Predominantly the level of contamination with heavy metals is low in the valley soils. A higher level was found in the area of the old city centre. Especially the contents of lead, copper and zinc were raised. Downstream of the sewage plant discharge into the river Warta increased contents of lead and cadmium were found. The distribution of heavy metals in the river Warta sediments indicates that the reason of the local increase of heavy metal contents is the sewage water discharge, Correlations between the content of different heavy metals and other soil properties (pH, clay and P-content, C/N-ratio) were calculated.     

Verlagerung von Chlorid und Nitrat in Lößmonolithen unter einfachen nicht-stationären hydraulischen Bedingungen

Nitrate and chloride transport in loess monolithes under quasistationary conditions The transport of nitrate and chloride has been investigated in an experiment with loess-monolithes under non-steady conditions and by a simple mathematical simulation technique approximating non-stationary flow by quasi-stationary conditions. Six precipitation cycles were followed by analysing soil solution drawn off by means of porous cups from the soil columns at different depths and times. At all times, the simulated “pure” transport profiles compare reasonably well with the experimental profiles. In the columns, however, nitrogen mineralisation took place during and before the experiment.     

Phosphatformen in Unterwasserböden Ca-reicher Fließgewässer

Forms of phosphates in underwater soils of Ca-rich running waters Underwater soils of small carbonaceous rivers in Upper Bavaria have phosphorus contents between 300 ppm in oligotrophic creeks and more than 0.2% in heavily polluted waters. The (Al,Fe)-P and the Ca-P occupied 20–35% and 28–38% of total phosphorus (P_t) resp., so that inorganic phosphates represent 53 to 64% of P_t. The correlation between P_t and carbonate is negative, but is positive between P_t and oxalate Fe or organic substance. Addition of P results in a relative increase of (Al,Fe)-P compared with other forms. Approximately 7 to 15% of total P is subject to isotopic exchange with ³²P.     

Bemerkungen zur Ermittlung der ungesättigten Wasserleitfähigkeit unter nichtstationären Bedingungen

On the Determination of Capillary Conductivity at Unsteady-State Conditions . Therefore it is stated that for obtaining the effective k_u-values. Considering the importance of capillary conductivity for the soil water regime the large differences up to 2 orders of magnitude between determinations on core samples from the same soil using the double-membrane-method (Henseler and Renger 1969) and the evaporation-method (Becher 1971a) initiated a study concerning the error caused by a possible nonlinearity of suction changes between two measuring levels using the latter method. The study was carried out on disturbed and undisturbed core samples from the three textural classes sand, silt and clay and with modified evaporation method. Comparing the geometric means of the obtained k_u-values calculated at unsteady-state and quasisteady-state conditions for different suctions resulted in that with usual application of the method the measured k_u-values must be diminished for obtaining the effective k_u-values. This correction factor increased with suction and is considered to be more important in laboratory than in field use.

• 1 For sandy soils a correction factor of 2 at 150 cmH₂O increasing to 6 at 1000 cm H₂O must be applied. The coarser the sand would be, at the lower suction nonlinearity will start and the more rapidly the correction factor will increase;.
• 2 For silty soils a correction factor of 2–4 must be applied for suctions > 300 cm H₂O;.
• 3 For clayey soils a correction factor of 2 rapidly increasing to 10 must be applied for suctions > 150 cm H₂O, but depending on soil cracks.

. The overestimation of water through-put resulting from the uncorrected k_u-values amounts to 1.5–4.0 [l/m² · d] at 100 cm H₂O, but these values are within the variation of the effective k_u-values. For 800cm H₂O the overestimation amounts to 0.002–0.065 [l/m² · d], but this makes up 300–1000 % of the effective water through-put.     

Fotometrische Messung der PEP-Carboxylase-Aktivität in Maisblättern unter Berücksichtigung des Entwicklungszustandes der Pflanze

Photometric estimation of the activity of phosphoenolpyruvate carboxylase in maize leaves as depending on plant development In order to measure photometrically the activity of Phosphoenolpyruvate carboxylase in homogenates of maize leaves, a method for larger test series was developed. When optimal conditions for the mixture, the pH-value and the temperature of the test mixture had been developed, reliable values were measured. The activities of Phosphoenolpyruvate carboxylase are dependant on the age of maize leaves. The activities increased during the first ten days of leaf development. The following twenty days were marked by a relatively small reduction of the activity. Thereafter a steady decline of the activity took place.     

Die Rolle der mikrobiellen Biomasse und des mineralisch fixierten Ammoniums bei den Stickstoff-Transformationen in niedersächsischen Löß-Ackerböden unter Winter-Weizen. I. Poolgrößenveränderungen

Significance of microbial biomass and non-exchangeable ammonium with respect to the nitrogen transformations in loess soils of Niedersachsen during the growing season of winter wheat. I. Change of pool sizes Nitrogen transformations in loess soils have been examined by laboratory and field experiments. After straw application (· 8 t · ha^?1), N in microbial biomass (N_mic) increased by about 20 mg · kg^?1 soil (· 90 kg N · ha^?1 · 30 cm^?1) after 9 days of incubation (20 °C). Another laboratory experiment yielded an increase of about 400 mg of NH₄+-N · kg^?1 fixed by minerals within 1 h after addition of 1 M NH₄+-acetate. Defixation of the recently fixed NH₄+ after addition of 1 M KCl amounted to only 60 mg · kg^?1 within 50 days. In a field experiment with winter wheat 1991, an increase in N_mic of about 80 kg N · ha^?1 · 30 cm^?1 was observed from March to June. After July, growth of the microbes was limited by decreased soluble carbon concentrations in the rhizosphere. Different levels of mineral N-fertilizer (0, 177 and 213 kg N · ha^?1) did not affect significantly the microbial biomass. The same field experiment yielded a decrease of non-exchangeable ammonium on the “zero”-fertilized plot in spring by 200 kg N · ha^?1 · 30 cm^?1. The pool of fixed ammonium increased significantly after harvest. After conventional mineral N-fertilizer application (213 kg N · ha^?1). NH₄+-defixation was only about 120 kg N · ha^?1 · 30 cm^?1 until July.     

Zur Interpretation erhöhter Schluffgehalte in Böden des Bayerischen und des Oberpfälzer Waldes

On the interpretation of raised silt contents in soils of the Bavarian and Upper Palatinate Forest For the Bavarian and Upper Palatinate Forest (Bavaria), 41 representative pedons were examined for aeolian components using grain‐size analysis. Soils derived from loess (three pedons) are only available in the foreland of the Bavarian Forest near to the river Danube. Soils with aeolian fractions (one pedon) also exist in the adjacent part of the Bavarian Forest. No indication for loess components (37 pedons) were found in all other parts of this mountain range: these soils are missing a coarse‐silt maximum in their upper layer as should be expected for loess‐influenced soils. However, 17 of these pedons have a medium‐silt maximum in their upper layer interpreted as a result of intense physical weathering. Therefore, the widely occurrence of soils with aeolian components cannot be confirmed for this low‐mountain range of E Bavaria.     

Die Wirkung von Klärschlamm auf die Kationenumtauschverhältnisse in einer Lößlehm-Parabraunerde unter Fichte

The effect of sludge application on cation exchange capacity of a loess loam Parabraunerde under spruce 5 years after sludge application the following effects on cation exchange capacity were found: Sludge application influenced soil chemistry to a depth of 10 cm. Cation exchange capacity was almost doubled in the layer of 0–5 cm, whereas in 5–10 cm only a slight rise was recorded. The proportion of exchangeable cations held by the soil, especially the relation between Ca: Al, was changed from 10:60 to 50:30 in the layer of 0–5 cm. The change was substantially lower in 5–10 cm. By separate analyses of samples the variation of cation exchange capacity as well as of the proportion of exchangeable cations was estimated.     

Nährstoffverlagerung und Wasserbilanz einer Braunerde aus Löß-Kolluvium unter Ackernutzuug

Nutrient displacement and water balance under oat crop on a Cambisol from loess colluvium Field experiments with oat on a loess soil were carried out from January until December 1978 on a since 6 years cultivated small plot area to study the water budget and the influence of different nitrogen fertilization on nutrient leaching. Ceramic cups were used to obtain soil water samples at a depth of 100 cm at two-week intervals, two years after application of a compost and after the application of artificial nitrogen fertilizers. Main components of the water balance were calculated with the use of a computer simulation (CSMP) program, the performance of which was controlled by tensiometer measurements. It was calculated that 214 mm of the total 608 mm rainfall in 1978 drained out of the profile, and that the cumulative evapotranspiration was 448 mm. This study included 70 stress days during which evapotranspiration was reduced. Chemical analyses of the soil solution samples showed that an intensive nitrogen fertilization surrendered to a significant increase in the nitrate displacement, whereas the average yearly losses of other nutrient elements, including potassium, phosphorus, calcium and magnesium were unchanged. The use of the compost fertilizer resulted in a significant increase in the sodium concentration of the soil solution samples.     

Anwendung des Agrarökosystemmodells EPIC zur Prognose des Wasser- und Nährstoffhaushaltes von landwirtschaftlich genutzten Flächen auf Sandböden in Ost-Brandenburg

Predictions of water and nutrient dynamics from agricultural sites on sandy soils in East- Brandenburg The validity of the agroecosystem model EPIC was tested for two agricultural sites on sandy soils without groundwater located at the moraine landscape in East-Brandenburg. Measurements of soil moisture, soil nitrate, above ground plant biomass and yield from these two agricultural investigation sites were compared with the corresponding simulation results of the model. The calculations of the soil water balance show a good fit between simulated and observed soil moisture values. The comparison between simulated and measured above ground plant biomass presents an underestimation of biomass by the model at the beginning of crop growth in spring and an overestimation at the end of the vegetation period. EPIC shows also an overestimation of yield in this study. The observed and the simulated soil nitrate values show no fit. Probably one reason for this fact might be the kind of process modeling included in EPIC, which was designed for long term calculations up to 50 years. Another possible reason could be the over estimation of N-uptakes of plants in comparison with estimates of the N-demand of plants based on the simulated yields. However a clear reason for the insufficient calculations of soil nitrate status by the model could not be found in this study. Further analysis of mineralization, N-uptake of plants and N-Ieaching in EPIC must be done in future.