Genauigkeit von Bodenfeuchtemessungen mit „Time Domain-Reflektometrie” und., Frequency Domain-Sensoren”︁ in heterogenen Waldböden

Precision of soil moisture measurements done with “Time Domain Reflectometry” and “Frequency Domain Probes” in heterogeneous forest soils Using “Time Domain Reflectometry” (TDR) and “Frequency Domain” (FD) technique soil moisture of a homogenized soil- substrate of silty loam was measured in the lab as well as soil moisture of the same silty loam and of two soils with coarser texture and more heterogeneous structure in situ. These measurements were compared with gravimetric soil moisture measurements done at the same measuring sites. Thus the measuring errors caused by soil heterogeneities should be assessed. The standard error of both, the TDR- and the FD- probes amounted to less than 1 Vol%, at the in situ measurements as well as in the homogenized substrate. In the homogenized substrate under relatively dry conditions soil moisture was overestimated to about 2 Vol% by both electronical methods, which is most likely the result of compactions in the contact zone between rods and the soil caused by the insertion of the rods. In the field both electronical methods, however, underestimated the soil moisture up to 14 Vol%. This applied especially to the surface of the mineral soil and under the influence of high stone contents. This deviation is interpreted as an effect of gaps along the rods, caused by the insertion. In loosely packed and stony upper soils we propose therefore to install the rods in homogenized autochtoneous soil material having settled to its natural bulk density instead of inserting them into the natural layered soil.     

Ertragssimulation mit “Ceres Wheat” an Grundwasserböden gemäßigter Klimazonen. Teil 2: Verifizierung des geänderten Modelles “Ceres Wheat”

Calibration of the simulation model “Ceres Wheat” under conditions of soils with shallow watertable and temperate climate. Part 2: Verification of the modified model “Ceres Wheat” The Ceres Wheat yield model has been adopted to soils under wet conditions and to humide climate. The basic assumptions of the modified model have been checked. The simulated results of the soil water balance, the plant development and the nitrate losses by drain discharge give fairly well agreements to field data from a Calcaric Fluvisol (Speicherkoog, Schleswig-Holstein). The modification improves the model and leads to the opportunity to simulate special aspects in agronomical and ecological advices.     

Accumulation soils like “Ockererde”—forgotten soil units in soil‐classification systems

Accumulation soils like those known as “Ockererde” are not yet represented in the German and in international soil‐classification systems, even though they represent important members of catenas found in humid low‐mountain areas influenced by the translocation of interpedon matter. Currently, this soil is referred to as “(Hang‐)Oxigley”, though this does not take into account its water and matter dynamics. Six representative catenas in the Black Forest (SW Germany) will be used to describe the occurrence, extent, and properties of the accumulation‐affected “Ockererde” derived from a variety of parent materials at specific altitudes. On the basis of their morphological, chemical, and physical properties as well as matter dynamics, it is possible to distinguish “Ockererde” clearly from soil units with similar characteristics (“Lockerbraunerde”, Andosols). Finally, suggestions will be given for the classification of “Ockererde”.     

”The principles of rational agriculture” by Albrecht Daniel Thaer (1752–1828). An approach to the sustainability of cropping systems at the beginning of the 19th century

The identification of quantitative fertility indicators for evaluating the sustainability of cropping and farming systems has become a major issue. This question has been extensively studied by the German agronomist Albrecht Daniel Thaer at the beginning of the 19^h century. In this paper Thaer's work is set in its historical background, from the end of the 16^th century (Palissy, 1580) to the middle of the 19^th century (Liebig, 1840). Then the paper focuses on Thaer's quantitative and complex fertility scale (expressed in “fertility degrees”), which was based on soil properties, on the requirement of nutrients by plants, and on the cropping system (including crop rotation). Thaer expressed soil fertility and economic results as a function of rye production in “scheffel of rye per journal” (ca. 200 kg per hectare). He also proposed a scale to describe the intrinsic fertility of soil. Thaer used this approach to assess the effect of major German cropping systems on soil fertility. He applied it to eight theoretical systems and nine existing systems in a true modeling approach. Thaer completed the fertility evaluation for the nine existing systems with a detailed economical analysis commenting the limits and potentialities of each system. Thaer's approach was used with success during half a century as it combined numerous empirical findings on soils and fertilization with organic substances in a sophisticated model. Unfortunately and despite effective practical applications, the scientific foundations of Thaer's “Humus Theory” proved definitively false as soon as 1840 when Sprengel and Liebig published on mineral nutrition of plants. Thaer's work deserves to be rediscovered since it approaches the modern issue of the sustainability of cropping and farming systems.     

Zu Eigenschaften,Horizontaufbau und Gliederung der „Haftnässepseudogleye”︁

Properties, horizons and classification of the “Haftnässepseudogleye” (Stagnosols periodically waterlogged with capillary water) The term “Haftnässe” (soil wetness due to capillary moisture) can be used in describing soils with Sg-horizons in which long-term waterlogging and anaerobic conditions occur in the absence of gravitational water. “Haftnässe” is caused by water held in pores with an equivalent diameter of 0.2–50 μm by soil-water tension (pF) between 1.8 and 4.2, when the air capacity of the horizons is very low. “Haftnässe” moves primarily by capillary forces and is available to plants (available water). In some soils, the horizon below the Sg-horizon contains large pores, is well aerated and tends to impede the movement of capillary water. This type of horizon is often wetter than the overlying and underlying horizons, due to the presence of capillary water in the immediately overlying Sg-horizon. The symbol “So” is proposed for such horizons. In these soils, in the Sg-horizon reduced iron compounds are oxidized and precipitated, forming rusty mottles. The sequence of horizons developed in the “Haft(nässepseudo)-gleye” (Stagnosols periodically waterlogged with capillary water) typically affects the continuity of the pathways along which capillary water normally moves. The “Haft(nässepseudo)gleye” are divided into two subtypes on the basis of the sequence of horizons in the soil profile:

• Typical “Haft(nässepseudo)gley” (Shn) exhibits a sequence Ah/Sg/(II)So and shows transitions to Luvisol and Glossisol,
• Thick “Haft(nässepseudo)gley” (Shm) exhibits a sequence Ah/Sg and shows transitions to “Stau(wasserpseudo)gley” (Gleysol periodically waterlogged due to perched water), Gleysol, Fluvisol and tidal marsh soil.

     

Characterization of a Unique “Super Soft” Kernel Trait in Wheat

Kernel texture in wheat (Triticum sp.) is central to end‐use quality and utilization. Here we report the discovery of a novel soft kernel trait in soft white winter wheat (T. aestivum L.). Two heritable kernel phenotypes were selected among F₃‐derived sibs, hereafter designated “normal soft” (wild‐type) and “super soft.” Normal soft lines exhibited single kernel characterization system (SKCS) hardness index (HI) values typical of soft wheat (HI ≈ 20), whereas the super soft lines were unusually soft (HI ≈ 5). Under some environments, individual super soft lines exhibited HI values as low as HI = –4. The super soft trait was manifested in reduced SKCS kernel texture and higher break flour yields, with some increase in sodium carbonate SRC (solvent retention capacity) values and sponge cake volumes. Straight‐grade flour yield, flour ash, milling score, and cookie diameter were largely unaffected. With the possible exception of the sodium carbonate SRC values, we observed no indication that the super soft trait conferred any negative aspects to commercial soft wheat quality. As such, the super soft trait may provide wheat breeders with new opportunities to modify the end‐use quality of wheat.     

Ertragssimulation mit “Ceres Wheat” an Grundwasserböden gemäßigter Klimazonen. Teil 1: Anwendungsgrenzen des Originalmodelles und Modelländerungen

Calibration of the simulation model “Ceres Wheat” under conditions of soils with shallow watertable and temperate climate. Part 1: Limitations in the applicability of the original model and necessary modifications To apply the yield simulation model “Ceres Wheat” under the specific climate conditions of Schleswig Holstein, the following modifications were necessary:

• Wheat development is strongly influenced by climatic conditions. Therefore the model has been adjusted to the temperate climate of Schleswig Holstein.
• The soil water balance routine of the model was originally designed for soils without oxygen deficiencies due to water logging. Routines for shallow water tables and artificial drainage were formulated.
• Due to modifications of the soil water balance routine, the associated nitrogen routine, especially the leaching of nitrate, has been changed.
• The simulation of yield depressions due to excessive water required the introduction of a trafficability delay function and an additional reduction factor for crop development.

All routines concerning the water and nitrogen balances and the quality of simulations have been tested under conditions of coastal marsh soils in Schleswig Holstein.     

On the Determination of the Constant Parameters of the “Two-surface” Langmuir Equation

The constant parameters k₁, k₂ (in ml/μg P) and b₁, b₂ (in μg P/g soil) of the two-surface Langmuir Equation for phosphate adsorption were determined by three methods for ten high pH montmorillonitic soils. The techniques included a graphical approach in which a curve is resolved into two straight line components (“Hofstee” method) and two methods utilizing the regression characteristics of the experimental adsorption data. The first regression method obtains estimates of k₁, k₂, b₁ and b₂ indirectly through various relationships resulting from the mathematical representation of the sorption isotherm as a “Stieltjes” transform (“Sposito” method). The second regression method obtains the parameters directly, assuming that k₁ ? k₂ and b₁ ? b₂ (“Approximation” method). Statistical analyses showed that each method yielded significantly different k₁ and k₂ constants compared to the other two. With regard to b₁ and b₂, the “Approximation” method produced significantly higher b₁ and lower b₂ values in all samples, though no difference was found among the three methods for the theoretical adsorption maximum (b_T=b₁+b₂). The relationship between k₁ and k₂ as well as b₁ and b₂, as expressed by their ratios, changed significantly from one method to another. This indicates the need for a more precise arithmetic definition of the condition k₁ ? k₂ and b₁ ? b₂ which is necessary for the “Approximation” method, accepted so far to be valid for k₁ ～ 100 k₂ and b₁ ～ 0,3 b₂ respectively.     

Mineralization of “non‐metabolizable” glucose analogues in soil: potential chemosensory mimics of glucose

Glucose is widely used to study the dynamics of easily available organics in soil. Pure culture studies have revealed that many microorganisms can sense and respond to glucose through chemosensory mechanisms that are not directly reliant on energy catabolism. However, the rapid mineralization of glucose by microorganisms makes it difficult to disentangle its energy effects from such non‐catabolic interactions. “Non‐metabolizable” glucose analogues have proven useful in mechanistic studies of glucose in pure culture, but have never been applied to complex microbial communities in soil. We sought to determine how their mineralization in soil differs from that of glucose, and whether they have potential as a new approach for investigating chemosensory mechanisms in soil microbiology. We incubated soil from an agricultural Haplic Luvisol under controlled conditions for 24 d and monitored CO₂ efflux after addition of (1) glucose, and three “non‐metabolizable” glucose analogues: (2) 2‐deoxyglucose (DG), (3) α‐methylglucoside (αMG), and (4) 3‐O‐methyl‐glucose (OMG), at three concentration levels, along with a control. All three analogues did in fact produce a large increase in soil CO₂ efflux, but the dynamics of their mineralization differed from the rapid degradation seen for glucose. At medium and high concentrations, CO₂ efflux peaked between 2.5 and 4 d after amendment with DG and αMG, and was delayed by about one week for OMG. The markedly different patterns of mineralization between glucose and OMG offer a new tool for investigating the behavior of glucose in soil. By using OMG as a glucose model, chemosensory mechanisms could be studied with limited interference from energy catabolism.     

Lime‐chlorosis occurrence and leaf mineral composition of grapevine treated by root microorganisms

One‐year‐old rooted cuttings of Vitis vinifera L. cv. Pinot blanc clone 55, grafted on “S.O.4” and “41 B” hybrid rootstocks, were grown in pots containing a calcareous soil. Before potting, the roots were infected by the VAM fungus (Glomus mosseae) and by a suspension of the following endophytic bacteria: Erwinia sp., Pseudomonas fluorescens, Enterobacter cloacae. The shoot growth was checked every ten days and leaf blade chlorophyll and mineral elements were assayed at the middle of the annual growing cycle as well as the mineral composition of the leaf petiole. Chlorosis was rated by visual screening as well in order to control the effect of the root treatments on the chlorosis occurrence. The most significant findings of the trial were: a) root infection with Erwinia sp. and Pseudomonas fluorescens increased the chlorophyll concentration over the untreated plants in both the graft combinations, b) the plants grafted on “S.O.4” rootstock did benefit from the treatment with Glomus mosseae as well, and c) root infection with Enterobacter cloacae depressed growth and chlorophyll concentration in both the graft combinations.     

Studies on growth and distribution of Na+, K+ and Cl− in soybean varieties differing in salt tolerance

Soybean plants, varieties “Lee”, “Jackson” and “Bragg” were grown in solution culture at various salinity levels. A NaCl concentration of 10 mM was already inhibitory to growth of “Jackson”; growth of “Lee”, however, was only reduced at a salt concentration of 50 mM or higher. The moderately salt tolerant variety “Lee” efficiently excluded Cl^? from the leaves up to about 50 mM NaCl in the medium, but showed high Cl^? contents in the root; exclusion of Na⁺ from the leaves was also apparent in this variety. On the other hand, the salt sensitive variety “Jackson” did not have the capacity for exclusion of Cl^? and Na⁺. The physiological behaviour of the variety “Bragg” resembled that of “Jackson”. It is suggested that the exclusion of Cl^? and Na⁺ from the leaves in the soybean variety “Lee” is regulated by the root.     

Effect of phosphorus management in rice–mungbean rotations on sandy soils of Cambodia

Nitrogen (N) and phosphorus (P) deficiencies are key constraints in rainfed lowland rice (Oryza sativa L.) production systems of Cambodia. Only small amounts of mineral N and P or of organic amendment are annually applied to a single crop of rainfed lowland rice by smallholder farmers. The integration of leguminous crops in the pre‐rice cropping niche can contribute to diversify the production, supply of C and N, and contribute to soil fertility improvement for the subsequent crop of rice. However, the performance of leguminous crops is restricted even more than that of rice by low available soil P. An alternative strategy involves the application of mineral P that is destined to the rice crop already to the legume. This P supply is likely to stimulate legume growth and biological N₂ fixation, thus enhancing C and N inputs and recycling N and P upon legume residue incorporation. Rotation experiments were conducted in farmers' fields in 2013–2014 to assess the effects of P management on biomass accumulation and N₂ fixation (δ¹⁵N) by mungbean (Vigna radiata L.) and possible carry‐over effects on rice in two contrasting representative soils (highly infertile and moderately fertile sandy Fluvisol). In the traditional system (no legume), unamended lowland rice (no N, + 10 kg P ha^?1) yielded 2.8 and 4.0 t ha^?1, which increased to 3.5 and 4.7 t ha^?1 with the application of 25 kg ha^?1 of urea‐N in the infertile and the moderately fertile soil, respectively. The integration of mungbean as a green manure contributed up to 9 kg of biologically fixed N (17% Nfda), increasing rice yields only moderately to 3.5–4.6 t ha^?1. However, applying P to mungbean stimulated legume growth and enhanced the BNF contribution up to 21 kg N ha^?1 (36% Nfda). Rice yields resulting from legume residue incorporation (“green manure use”–all residues returned and “grain legume use”–only stover returned) increased to 4.2 and 4.9 t ha^?1 in the infertile and moderately fertile soil, respectively. The “forage legume use” (all above‐ground residues removed) provided no yield effect. In general, legume residue incorporation was more beneficial in the infertile than in the moderately fertile soil. We conclude that the inclusion of mungbean into the prevailing low‐input rainfed production systems of Cambodia can increase rice yield, provided that small amounts of P are applied to the legume. Differences in the attributes of the two major soil types in the region require a site‐specific targeting of the suggested legume and P management strategies, with largest benefits likely to accrue on infertile soils.     

Sunflower ( Helianthus annuus L.) Seeding Rate Additions to Forage Oat-Legume Mixtures in Newfoundland

Lingonberry (Vaccinium vitis‐idaea L.) cvs “Sussi”; and “Sanna”; were cultivated on mineral soil with four different soil surface treatments (Sphagnum peat mulch, sand mulch, plastic mulch and herbicide 3‐syclohexyl‐5, 6‐trimethylenurasil (lenasil)). Amount of annual weeds, plant coverage and yield were observed over five years. Weeds were most abundant in the first two observation years. Sand mulch was the least efficient for the control of annual weeds for both cultivars, whereas lenasil was the most efficient for “Sussi”;, and peat mulch for “Sanna”;. The plant coverage increased steadily throughout the years in the “Sussi”; plots, especially in plots mulched with peat. The spreading of “Sanna”; was slower in all treatments. It was best in plots mulched with peat or sand. Overall, “Sanna”; was more productive, with the highest yield on sand mulch and the lowest on lenasil‐treated plots. “Sussi”;, instead, yielded best on lenasil plots and poorest on sand.     

Should farmers apply fertilizer according to when their daffodils are in flower? Utilizing a “farmer‐science” approach to understanding the impact of soil temperature on spring N fertilizer application in Wales

Perennial ryegrass starts growing when soil temperatures reach 5.5°C for five consecutive days; applying N fertilizer before this risks environmental losses. To test whether daffodil flowering signified when to apply N fertilizer, farmers volunteered to take part in a citizen science study. The PROSOIL project used a “citizen science”, participatory approach to create farmer‐informed science, aiming to increase awareness of the importance of soil health. In 2014, over 300 farmers completed a “How do you manage your soil” survey. The survey included a question on the use of daffodils (Narcissus spp.) to indicate the best time to apply the first nitrogen fertilizer of the season, based on anecdotal feedback from farmers involved in the PROSOIL project. The survey recorded 7% of farmers based their first fertilizer application on when daffodils flowered. To increase farmer awareness of soil temperatures, we provided them with soil thermometers, held workshops and hosted interactive stands at agricultural events in 2014. In autumn 2014, farmers planted daffodil bulbs of the same variety, across Wales, and monitored soil temperatures. Farmers returned postcards once their daffodils were in flower, noting the soil temperature. An assessment of whether daffodil flowering date could indicate when to apply N fertilizer was made. Overall, in spring 2015, daffodils flowered when soil temperature was 6.4(±0.35)°C, suggesting daffodil flowering date is a more reliable indicator for fertilizer application, than first hypothesized. Findings show a scientific validation of local knowledge, regarding the use of daffodils to indicate the “not‐before” date for the first N fertilizer application.     

Vergleichende Betrachtung von Verfahren zur Auswertung von Nährstoffsteigerungsversuchen am Beispiel Phosphor

Comparison of two procedures to evaluate phosphate‐fertilizing field trials Growth response of agricultural crops to different input levels (e.g., fertilizer rates) can be described by the “law of diminishing increments”, which has been formulated mathematically amongst others by Mitscherlich (1928) and von Boguslawski and Schneider (1962, 1963, 1964). In the present paper, the economically optimal phosphate‐fertilizer requirements in 43 long‐term phosphate (P)‐fertilization experiments were calculated using equations on the basis of the yield functions of Mitscherlich or von Boguslawski and Schneider, respectively. For three field trials with linear or disproportionately high yield responses on P fertilization, none of the two procedures could be used. The same held for four trials with maximum yields already appearing at the first fertilization level. Similar P‐fertilization optima were calculated for 36 trials following the “law of diminishing increments”, resulting in a highly significant correlation (R² = 0.946) between both procedures. The correlation coefficients between the phosphate balance at the calculated optimum profitability and CAL‐P content in the soils at trial start were R² = 0.70 (Mitscherlich, 1928) and R² = 0.65 (von Boguslawski and Schneider, 1962, 1963, 1964), respectively. An optimal soil P content of 8–10 mg CAL‐P (100 g soil)^–1 was deduced. Both methods are applicable to calculate the optimum phosphate‐fertilizer requirement if yield effects due to P fertilization follow the “law of diminishing increments” and the increments of fertilization levels in each trial are established in a way that diminishing yield increments can be expected.     

Veränderungen physikalischer Bodenmerkmale im „Statischen Düngungsversuch”︁ während einer Vegetationsperiode

Temporal variations of physical soil properties in the “Static Fertilization Experiment” The objective of the present paper was to observe short-term changes in physical soil properties of a differently fertilized loess-Chernozem. Samples were taken weekly from the plots with 17.2 g C_org kg^?1 (unfertilized) and 25.0 g C_org kg^?1 (NPK + farmyard manure) of the “Static Fertilization Experiment”, Bad Lauchstädt, and their moisture contents (θ), bulk densities (?_d) and particle densities (?_s) were determined. The soil moisture contents showed very similar variations in the two treatments. Clear differences between the unfertilized (≈ 16 Vol.-%) and the NPK + farmyard manure treatment (≈ 10 Vol.-%) only occurred during summer (means 25th–29th week). The values for ?_d were lower in the NPK + farmyard manure plot (mean: –0.10 g cm^?3). Similar short-term changes in ?_d were found in both treatments and correlated to both, organic matter contents and composition (C_org, N_t, C/N). These data, however, gave no indication of reasons for the short-term changes in particle densities up to 0.09 g cm^?3.     

Zur Definition von Humusformen ackerbaulich genutzter Böden. II. Quantität und Qualität der organischen Bodensubstanz

The definition of humusforms from soils under cultivation. II. Quantity and quality of soil organic matter In the new edition of the German textbook “Practical Studies in Soil Science” the authors presented a proposal of mapping humusforms in arable soils in order to characterize soil and site ecology (Schlichting et al., 1995). This proposal was developed from the definitions “Ochric”, “Mollic” and “Umbric” of the Soil Taxonomy and the FAO classification. The characterization of humusforms in 45 arable surface soils was carried out according to this proposal while soil organic matter (SOM) composition was investigated by means of wet chemistry and CPMAS ¹³C-NMR spectroscopy. “Mollic” in contrast to “Umbric” humusforms could be characterized by a higher carbonyl/carboxyl carbon content probably deriving from proteins, polysaccharides and humic substances. In addition the mollic epipedon contains 10% more litter compounds, whereas in the umbric epipedon humic acids are of major importance. The humin fraction in the mollic epipedon is thought to be raised by the formation of Ca-humates. Our data suggest, that with regard to microbial decomposition a surplus of available organic matter is present in the mollic horizons. The ochric-like epipedon has a much lower humus content compared to “Mollic” and “Umbric” horizons and exhibits the highest amounts of soluble organic matter as well as aromatic and carboxylic C-compounds in the humic fraction. Our data suggest, that SOM quantity and quality of the mollic, umbric and ochric epipedons differ substantially. These findings suggest that the proposal of Schlichting et al. (1995), which was extended by Blume & Beyer (1996), should be regarded as a useful basis to discuss the development of humusforms in soils under cultivation and facilitate soil survey in order to improve site characterization.     

Growth and mineral nutrition of cattails inhabiting a thermally‐graded South Carolina reservoir: I. Growth and the macronutrients 1

Growth and macronutrient uptake in two species of cattail, Typha latifolia and T. domingensis, were determined during an annual growth cycle in Par Pond, a thermally‐graded nuclear reactor cooling reservoir in South Carolina. Shoots of the same age class were sampled periodically from the initiation of growth in early spring to senescence in late autumn. Although differences between thermal regimes were mostly statistically non‐significant, growth and macronutrient uptake, especially of N, P, and K, tended to be enhanced by elevated water temperatures. The pattern for growth and N, P, and K uptake in decreasing order were: “Warm”; > “Intermediate”; > “Ambient”; regimes. The non‐significant statistics were attributed to large between‐stand and between‐temperature regime variations. Both Typha species exhibited sharp declines in N, P, and K concentrations in the shoots, and some decline in the rhizomes, early in the growing season, followed by either a more gradual decline or leveling off of concentrations until senescence. Calcium in shoots of both species increased with season, whereas Mg remained fairly constant. Thermal effluents can alter the growth form of Typha, as confirmed by the elimination of T. domingensis in the “Warm”; regime, and can affect their mineral nutrition.     

Beziehungen zwischen “verfügbarem” Bodenphosphat und den Phosphatblattgehalten von Tectona grandis (Teak) in Westafrika

Relationships between “available” soil phosphorus and foliar phosphorus content of Tectona grandis (teak) in West-Africa Significant relationships were analysed between the foliar phosphorus content of Tectona grandis L. and the topsoil phosphorus contents on a broad range of soils in West African plantations of Tectona grandis L. (teak), except for soils very poor in clay or organic matter (< 15% T or < 1% C). Of all methods used (P-H₂O, P-Mehlich, P-CAL, P-Bray-1, P-Soltanpour, P-Dabin, P-Resin, P-H₂SO₄, P-550, P-org) the fraction of soil P (P-550) dissolved in 1 n H₂SO₄ after dry ashing at 550 °C (r = 0.548^***, n = 63) and the method of Bray-1 (r = 0.505^***, n = 63) show the best results. The first reflects 80-90% of the organic P content and is recommended for the evaluation of the phosphorus supply. Using multiple correlation analysis we found a highly significant relationship (R = 0.794^***, R² = 0.63, n = 58) between foliar P as depending variable and P-Bray (positive), the soil sand content (negative) as well as soil pH (positive). A sufficient phosphorus supply of teak foliage (0.2% P) occured at soil levels of 300-320 kg P per ha and 15 cm (or more than 150 mg P/kg in topsoils free of stones (P-550)) in the studied area between Benin and Liberia.     

Die „Baumfuß-Methode”︁, dargestellt anhand einer Untersuchung der Immissionsbelastung von Nordwest-Jugoslawischen Buchenwäldern

The “Trunk Base Method”, Demonstrated by an Investigation on Immission Load of Beech Stands in Northwestern Yugoslavia Due to stemflow, the soil area close to the stem of old beech trees (Fagus sylvatica) differs from the soil farther from the stem as a consequence of higher input rates of all elements. It is postulated that the level of deposition determines the degree of deviation in soil chemical properties of the trunk base area (“Baumfußbereich” = “micro-habitat”) compared with soil which is not influenced by stemflow water (“Vergleichsstandort” = “macro-habitat”). The paper attempts to estimate the relative load of air pollution in 10 beech stands (mainly Rendzinas and Cambisols from limestone and dolomite) of northwestern Yugoslavia. In each plot 10 micro- and macro-habitats were chosen, for analysis of soil samples of Ah horizons for pH and exchangeable cations after percolation with NH₄Cl. The differences in pH, base saturation and saturation of (H+Fe) between trunk base area and related soil are used to determine acid loading. The saturation of (H+Fe) turned out to be the most appropriate indicator to describing the acidification. The results indicate high acid deposition rates at sites 1–5,9 and 10, but low rates at stands 6–8. It is assumed, that the main sources of pollutants reaching the plots 1–5, which are located at the western declivity of Risnjak, are industrial plants in northern Italy and towns at the Adriatic coast. The sources of pollutants reaching the sites 9 and 10, which are located at the eastern declivity of Gorski Kotar, respectively Lika region, are the industrial plants in northern Yugoslavia and Hungary.