Theoretische Betrachtung des Ionenkreislaufs in Waldökosystemen

Theoretical consideration of the ion cycle in forest ecosystems From the law of mass conservation and the principle of electrical neutrality it is deduced for forest ecosystems being in steady state that proton production or -consumption during ion uptake is balanced by opposite proton turnover during mineralization. With a beech (Fagus silvatica) forest ecosystem in the Solling as an example it is shown that the turnover of nitrogen plays a key role in this respect. Temporal and spatial discoupling of the ion cycle cause acidification pushes and deacidification phases. It is distinguished between seasonal acidification pushes, which are regulated by weather conditions, and climatic acidification pushes, which are regulated by climate fluctuations. Strong long lasting reductions of the phytomass production, as caused by strong changes in climate or by human interaction, can lead to instationary states. It is distinguished between two consecutive instationary states, which are connected with soil acidification: humus-disintegration and podzolization. It is concluded that an acute podzolization in its beginning stage, which appears at present in deciduous forest and older stands of spruce and pine, cannot be caused by ecosystem internal reasons, but is the consequence of acid precipitation.     

Bodenchemische Vertikalgradienten als charakteristische Zustandsgrößen von Waldökosystemen

Soil chemistry depth gradients as characteristic state variables of forest ecosystems Based on model concepts and on analyses of the soil solution and the soil solid phase we present a procedure to predict the cation composition of the soil solution from solid phase properties. For the intended prediction, the aluminum (or base) saturation (NH₄Cl extraction) of the soil exchange complex yields the best results. This parameter shows distinct gradients through a soil profile, and these gradients can be used to characterize the state of the ecosystem. We suggest to utilize this parameter as an additional criterion in the practice of forest site classification.     

Ordination von Waldökosystemen nach Stoffkonzentrationen der Lösungsphase und bodenchemischen Tiefengradienten

Ordination of forest ecosystems using element concentrations of the solution phase and soil chemical depth gradients Using data sets from 16 forest ecosystems the possibilities of an ordination procedure with respect to matter budget parameters are demonstrated. Principal component analysis was selected as method of ordination. Ordinations were carried out separately for (i) depth gradients of base saturation, for (ii) average element concentrations in the soil solution at two different depths, and (iii) for element concentrations in the bulk deposition and the throughfall. In the majority of cases the procedure yields plausible and interpretable arrangements of the ecosystems along the first and the second principal component axes. These two components contain over 80 percent of the total variance in the datasets. Compared to other methods of ecosystem characterization the ordination procedure is advantageous concerning practicability and objectivity. It is suggested to apply the method to a larger set of forest ecosystems with the aim of grouping the systems according to their individual states. An additional application is the analysis of temporal changes as attempted in ecosystem monitoring.     

Raten der Deposition,der internen Produktion und des Umsatzes von Protonen in zwei Waldökosystemen

Rates of deposition, of soil internal production and of turnover of protons in two forest ecosystems The rates of deposition, of turnover and of soil internal production of protons are calculated from the flux balance of chemical elements within two forest ecosystems (Dystic Cambisols from loess/sandstone with beech or spruce). The rates of interception deposition vary significantly throughout the season and determine the rates of total deposition to a large extent. The comparison of the actual rates of proton load with the buffer rates possible in the soils leads to the conclusion that soil acidification up to the level of the Al-buffer range is unavoidable in most forest soils in Middle Europe. The behaviour of the incoming S in the soil is related to the dissolution and precipitation of Al-hydroxo-sulfate. The accumulation of S within the soil of the spruce stand was found to be reversible and was followed by a phase of strong leaching of S and Al from the soil. The processes that account for the rates of soil internal proton-net-production are quantified. More than 70% of the total proton load results from the deposition of air pollutants while only less than 30% is of soil internal origin.     

Bodenstruktur und Regenwurm-Aktivität in einem Wiesenboden im Solling

Soil structure and earthworm activity in a meadow soil in the Soiling area The A-horizon of a Golden Oat Meadow (Trisetetum flavescentis OB) in the Solling was analyzed micromorphologically and micromorphometrically. Five tables with magnifications of the soil structure form an essential part of the presentation. The upper 8-10 cm of the soil consist mainly of earthworm castings with different density of deposition. By these a spongy structure, stable against water, was formed in the upper 3-5 cm of depth. But also in the deeper horizons the soil bulk is penetrated by a net of pores of different width, causing a favourable water capacity as well as allowing sufficient air for the roots.     

Fracht an chemischen Elementen in den Niederschlägen im Solling

Loading of chemical elements in precipitation at the Solling For the period 1969–1976 (NH₄, NO₃: 1971–1976) monthly values of concentrations and flows of the ions NH₄, H, Na, K, Ca, Mg, Fe, Mn, Al, Cl, NO₃, SO₄, P and organic bound N in precipitation are passed on. From the correlations between elements the following main ion sources are concluded: sea water (Na, Cl), combustion processes (SO₄, NO₃, NH₄), lime dust after dissolution by H₂SO₄ and HNO₃ (Ca, Mg), soil dust after dissolution by H₂SO₄ and HNO₃ (Al, Fe), leaching from plants (K, NO₃, SO₄, Mg, Ca), biogenic contaminations (P, organic N, K, NH₄, NO₃). Seasonal variations in the concentrations are most evident for Na and Cl, less for NH₄, SO₄ and NO₃. During the measuring period the flux of NH₄ is significantly increased; for H and SO₄, less for NH₄, Mg, Ca and Fe, the increasing trend was interrupted in winter 1973/74 (oil crisis). Consequences for sampling are discussed.     

Mathematische Modellierung der Funktionen des Bodens im Stoffhaushalt von Ökosystemen

Mathematical modelling of the role of soil in ecosystem functioning The structure of ecosystems and the parameters necessary for their characterization are discussed under the aspect of matter balances. The main weight is layed on the regulatory role of transport processes and storage changes in soil. It is postulated that the quantitative ecological analysis of landscapes requires the application of computer models of the regulatory processes in soil as a method for minimizing the measuring expense. The basic equations describing transport processes and storage changes are discussed and their application for special problems of the balance of water and chemical elements is demonstrated.     

Abschätzung der organischen Kohlenstoffeinträge in Waldökosysteme durch Messung der UV-Absorption (254 nm) im Niederschlagswasser

Estimation of organic carbon deposition into forest ecosystems by determination of the spectral absorption of rainwater in range of ultraviolet radiation (SAC₂₅₄) Organic compounds are mostly neglected within deposition measurement programs because their determination is expensive and complicated. A very simple and rapid estimation of total organic carbon (TOC) is possible by determination of the spectral absorption coefficient in the range of ultraviolet radiation at 254 nm wave-length (SAC₂₅₄): TOC (mg/1) = 0,5 SAC₂₅₄ (m^?1) - 0,15     

Beitrag zum Elementaustrag mit dem Sickerwasser unter verschiedenen Ökosystemen im nordwestdeutschen Flachland

Contribution to the element output with seepage under different ecosystems in the flat plains of Northwest Germany Over a period of one year samples of seepage water were taken from 3 different ecosystems of the pleistocene lowlands of Northwest Germany. A mixed crop of oak, a pure pine forest and a heathland area were chosen. The ions H, Na, K, Ca, Mg, Mn, Fe, Al, PO₄, SO₄, Cl, NO₃ and NH₄ were analysed. A balance calculation was done based on measurements or estimations of total evaporation and on measurements of element input with rainfall. The data indicate different interception (dry deposition) rates of air pollutants for the 3 stands. Al-ions were found in the soil solution under the pine stand and under the heathland area in a depth of 1.2 m. This status has not yet developed in the soil of the oak stand, but seems to be reached soon.     

Rekonstruktion des Ausgangszustandes und Bilanzierung von Böden einer Moränenlandschaft

Reconstruction of the original composition and balancing of soils developed on glacial till In this paper a method for the reconstruction of the original composition of soils formed on heterogeneous glacial till is described. As an exampel the original contents of carbonates, iron and clay were calculated in two soils. The soils investigated are “Rostbraunerde” under forest and ?Braunerde”? under meadow. The “Braunerde” has been regularly irrigated with waste water for the last 70 years. The heterogenity of the fine earth of the parent material is caused by the successive deposition of materials with varying particle size distribution as well as in situ cryoclastic weathering of the different rock fragments. The reconstruction was calculated from the relation between the above mentioned weatherable components and less weatherable components in the pleistocenic sediments of Berlin. The sorting grade (So, Muller, 1962), median (Md) of the particle size distribution in the 2–600 γ fraction and the contents of coarse sand, Zr and Ti in the fraction 2-2000 pm were considered as unweatherable. The calculations were performed using multi regression analysis. The influence of the pedogenetic processes of decarbonatisation, acidification, clay formation and clay migration as well as the pedological changes resulting from the waste water irrigation were quantified through the comparison between the calculated original and the measured actual contents of the weatherable components.     

Flüssebilanzen und aktuelle Änderungsraten der Schwermetall-Vorräte in Wald-Ökosystemen des Soiling

Flux balances and current rates of change of heavy metal stores in forest ecosystems of the Soiling The inventory of the heavy metals Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb is calculated for a beech and a spruce forest ecosystem in the Soiling mountains on the basis of measured concentrations in the vegetation and soil compartments and their dry mass per hectare. The inventory is compared with measured heavy metal fluxes coupled with precipitation above and below the canopy, with seepage water fluxes below the rooting zone (50 cm depth), with litterfall, and with the current increment to biomass. The ratios between heavy metal stores in the forest floor layers (table 3) and the annual flux with litterfall (table 4) show decreasing tendency for liberation of the elements by decomposition of organic matter (OM) in the following order: Mn>OM>Ni>Cd>Cu>Cr ≈? Zn>Co ≈? Fe ≈? Pb Manganese is set free faster than total organic matter. The flux balances for the total ecosystems (table 4) show input > output in the case of Cr, Fe, Cu, Cd, and Pb; input ≈? output for Ni and Zn; input < output for Mn and Co. Heavy metal stores in mineral soil are decreasing by percolation losses and increment to biomass (mainly wood) in the case of all elements investigated, except Zn (under beech), Cd and Pb (table 4). The concentrations of Cu and Pb in the forest floor layers have reached levels at which deleterious effects on microorganisms and litter decomposition are to be expected.     

Einfluß 85jähriger differenzierter organischer und mineralischer Düngung auf Bodeneigenschaften im Statischen Versuch Bad Lauchstädt

Influence from a 85-year differentiated organic manuring and mineral fertilization on soil fertility in the static experiment at Bad Lauchstädt The results of the static experiment started on chernozem from loess at Bad Lauchstädt in 1902 are used to demonstrate the influence of differentiated organic manuring (no manuring, 20 t and 30 t ha^?1 of farmyard manure) and mineral fertilization (NPK, NP, NK, N, PK, no fertilization) on the organic matter and nutrient contents in soil. After 85 years the content of organic C (C) in the topsoil was higher by 0, 5% after organic and mineral fertilization than after mineral fertilization. Exclusive mineral fertilization (NPK) increased the C-contents in soil by 0, 2% than without fertilization. Farmyard manure considerably reduced nutrient deficiency, which is due to plots without mineral fertilization. This holds especially true for potassium and phosphorus deficiencies. With rising pH value the Mn content in the soil diminished.     

Wirkung der Phosphatdüngung in einem 40jährigen Dauerversuch auf einer Sandlöß-Braunschwarzerde in Halle

Effect of differential P fertilizer application over a period of 40 years in a long-term field experiment on a Phaeozem near Halle, Germany P fertilizer in three forms was applied at 0 (P₀), 15 (P₁) and 45 (P³) kg ha^?1 P per annum to a relation lucerne — lucerne — potatoes — winter rye — sugar beet — spring barley. The experiment was laid down in 1949 near Halle on Phaeozem soil containing 57 mg total P and 8.5 mg DL-P per 100 g soil (0–20 cm) and with pH 6.0 (0.1 M KCl). Small differences between treatments were first observed only after 20 years. Since then the effects of treatment increased but even after the 7th cycle (1982–1987) the maximum effect was <8 cereal units (CU) per ha. The crops most responsive to P were: lucerne (in the year of sowing), potatoes and sugar beet. Over the period 1977–1988, annual P removal exceeded P input by 23 and 9 kg ha^?1 P for treatments P₀ and P₁ respectively; on treatment P³, P input exceeded removal by 19 kg ha^?1 per annum. DL-P on treatment P₀ in 1979 was 3.5–4.0 mg per 100 g, insufficient to support high yields. A level of 5–6 mg DL-P per 100 g soil, as found in treatment P₁ is required for sustainable high yield. Change in total soil P content corresponded with the P balance (input — withdrawal) only on treatment P³. The lack of correspondence on treatments P₀ and P₁ suggests that crops obtained much of their P requirement from subsoil.     

Bilanzierung der Tonbildung und -verlagerung sowie der Tonmineralumwandlung in Löß-Parabraunerden

Balances of alteration and migration of clay fractions and clay minerals in Gray Brown Podzolic Soils from Loess Balances of alteration and migration of clay fractions, clay minerals, K, Mg and Fe bound in clay silicates were calculated for Gray Brown Podzolic Soils (Parabraunerden) derived from Young Pleistocene Loess below arable and forest land in the district south of Würzburg. The extent of clay formation lies between 63 and 98 kg/m², of which 60–80 % belong to the fraction <0.1 μm. The clay migration varies between 35 and 51 kg/m², the fractions < 0.2 μm (especially the fraction <0.1 μm) predominating, the coarse clay being involved only to a smaller extent. During Holocene soil formation 121 kg illite, 16 kg vermiculite and 11 kg kaolinite per m² are formed in the clay fraction (< 2 pm). The loss of smectite amounts to 68 kg/m². The biggest alterations of the clay mineral quantities occur in the fraction <0.1 pm; they indicate a smectite-illite transformation. Illite, at 23 kg/m², accounts for half of the clay migration, followed by smectite and vermiculite each at 9 kg/m² and kaolinite at 5 kg/m². When comparing the migrated with the present amounts no preference of certain clay minerals during clay migration can be determined. In the clay fractions the gained Fe (3.07?4.32 kg/m²) and K (2.75?3.84 kg/m²) predominate over Mg (0.57?1.15 kg/m²). The three elements accumulate to the greatest extent in the fine clay fraction. The element migration parallels the gain. The balances of the elements are discussed in connection with pedogenic illite formation as well as biotite and vermiculite disintegration.     

Zur Dynamik gelöster organischer Substanzen (DOM) in Fichtenökosystemen - Ergebnisse analytischer DOM-Fraktionierung

Dissolved organic matter (DOM) dynamics in spruce forested sites - examinations by analytical DOM fractionation Dissolved organic matter from two spruce forested sites in the Fichtelgebirge (Germany) was divided into different chemical and functional fractions, and the budgets of the fractions obtained were calculated. For both sites hydrophobic acids (HoS), hydrophilic acids (HiS), hydrophobic neutrals (HoN), hydrophilic neutrals (HiN), and hydrophilic bases (HiB) are discriminated concerning their dynamics in the compartments. Most of the HiN and HoN are mobilized by leaching from the forest canopy. Both neutral fractions are netto retained in the forest floor as well as in the mineral soil. In contrast, HoS and HiS are mainly released in the organic layers with a total input of organic acids from the forest floor into the mineral soil of ca 100 kg C (HoS) ha^?1 a^?1, and 50 kg C (HiS) ha^?1 a^?1, respectively. HoS are selectively better retained in the mineral horizons, leading to a mineral soil output of 2.4 – 4.4 kg C (HoS) ha^?1 a^?1, and 2.7 – 6.5 kg C (HiS) ha^?1 a^?1, respectively. It is concluded that the different mobility of the DOM fractions has implications for the mobilization and transport of organic pollutants and heavy metals.