Löslichkeit des anorganischen Bodenphosphors und Phosphatdüngung

Solubility of the inorganic soil phosphorus and fertilizer phosphate The solubility of the inorganic soil phosphate of different soils was determined in up to 40 consecutive extractions with water and lactate solutions. The graphs showing the relationship between total extracted P, and P concentration in the extract ants (Fig. 1 and 3) were of an exponential type, independent of chemical bonding of the soil phosphorus, and independent of other soil properties. P contents in the first extractions were closely correlated with the sum of the P contents of all extractions with a solubility > 100 μg P/1 (fig. 2). All of the soil phosphate capable of diffusion is plant available. Therefore all phosphate in the soil which originated from fertilizer phosphate will be utilized. This follows from the data of solubility of the soil phosphorus (20–140 μg P/1) after repeated water and lactate (CAL) extractions. The slow adjustment of equilibrium, which is common with phosphate adsorption experiments is due to the influence of diffusion. The relationships between P fertilization, solubility of soil phosphate, and the recommended soil P content for economical P utilization with optimum plant growth (e.g. Tab. 2) is shown.     

Wasseraufnahme und Wasserverbrauch von Ackerbohne und Hafer auf einer Löß-Parabraunerde

Water uptake and water use of field beans and oats grown on a loess-derived grey-brown podzolic soil (Eutroboralf) The terms of the water-balance equation were determined, when field beans (Vicia faba L.) and oats (Avena sativa L.) were grown on a loess-derived soil during two seasons (1982 and 1983). A specific objective of this investigation was to quantify the water uptake from different layers and the total transpiration of both crops, as field beans are known to be susceptible to water shortage. Beside soil physical measurements climatological data for calculation of potential evapotranspiration were recorded. Plants were analyzed due to leaf area and root length density once a week. Actual evapotranspiration including interception, as determined by the soil physical approach, was split up by calculation procedures into actual evaporation, interception and actual transpiration. Total root length and root length density of field beans were much smaller and the rooting system was shallower as compared with oats. Development of leaf area and of roots was slower with beans than oats and was retarted by 2 to 3 weeks. Accordingly the time of maximum transpiration was found begin of June with oats and at begin of July with field beans. Despite reduced root growth Vicia faba transpired 250 mm in total, that is 86 % of what was found for the cereal crop (290 mm). Water uptake field beans however, was restricted to the upper 80-cm profile with 90 % of total uptake. The water uptake per unit length of root was substantial higher with beans than with oats. Due to the delayed development of the bean crop the losses by evaporation and seepage exceeded those from the soil grown to oats by 40mm (64 %). These investigations support the conclusion that yield stability of field beans may be substantially improved by selection of new varieties with increased rooting depth.     

Initiale Bodenentwicklung in aufgespültem Löß und Hafenschlick

Initial soil development in loess and harbourbasin mud reclaimed by slurry poldering In the Rhenish Brown Coal Strip Mining Area initial soil development was investigated for 6–15 and 15–25 years old loamy-silty loess soils reclaimed by slurry poldering. In the Emden environs the same analyses were applied to 6, 17, and 28 years old silty-clayey harbour-mud soils, also reclaimed by slurry application. The most prominent results when comparing these two types of soil are as follows: The mud soils show higher contents of clay and organic matter. Therefore they reveal more favourable characteristics concerning cation-exchange capacity, soil physical and soil biological properties in comparison to those of the loess soils. In both types of soils cation-exchange-capacity and soil biological activity increase in the Ap-horizon over time. The soil physical characteristics of the mud soils markedly improve in the run of the development, whereas those of the loess soils hardly improve. It remains a subject of discussion, since what stage of development mud soils should be classified as sea-marshes/“Kleimarschen” and loess soils as rendzinas.     

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.     

Beziehung zwischen Bodenorganismen und Gefügeentwicklung auf Löß-Neuland unter Acker- und Waldnutzung

Relationship between soil organisms and soil structure in new reclaimed soils derived from loess under agricultural and forestral use In the Rhenish Browncoal District est of Cologne he question occurs wether forestry or agriculture is the better form of primary use to force structure development in new reclaimed soils derived from loess. The investigations on 10–25 years old reclaimed soils under forestral and agricultural use indicate that humus content, microbiological activities as well as the number of soil meso- and macrofauna individuals like earthworms are increasing with growing age of the forest soils. These processes and the strucutre development are faster under forestral use. Here after about 20–30 years conditions are similiar to those of undisturbed forest soils in comparable substrates. So from the ecological point of view temporal priority should be given to forestral use.     

Al-Spezies im Sickerwasser saurer Waldböden - Einfluß von Wasserbewegung und Löslichkeitsgleichgewichten

Aqueous Aluminum Species in Acidic Forest Soils - Influence of Water Pathways and Solubility Equilibria In the seepage of three typical Black Forest soils (Haplic Podzol, Dystric Cambisol, Dystric Planosol) the fractions ‘Labile-Monomeric Al’, ‘Stabile-Monomeric Al’ and ‘Acid-soluble Al’ were analyzed. Activities of aqueous Al species and saturation indices (SI) with respect to various Al-bearing minerals were calculated from ‘Labile-Monomeric Al’, using the computer program WATEQF. Al-mobilization/immobilization processes were evaluated by means of AI/CI molar ratios. With 1.5 mg/L in average, the Al_total concentrations are relatively low in all studied soils. In the O-horizon leachates, 70 to 80% of aqueous Al occur as ‘Stabile-Monomeric’ and ‘Acid-soluble’ forms mainly consisting of organo-complexes. This portion decreases in the mineral soil to 35% in the podzol and the planosol as well as to 10% in the Cambisol. Simultaneously, Al³⁺ increases to 40% (planosol), 50 (podzol), and 70% (cambisol). In all horizons, 5 to 15% of Al_total are covered by Al-fluoride-complexes, whereas Al-sulfate-complexes are insignificant. With 5 to 10% monomeric Al-OH-ions play a role only in the subsoil. Aluminum is strongly mobilized in the upper mineral horizons of all studied soils. In the planosol and the cambisol, Al is immobilized in the subsoil. In the subsoil of the podzol, in contrast, Al reveals further mobilization due to a distinct internal production of HNO₃ and H₂SO₄ as a consequence of mineralization of organic matter. In the podzol, rapid percolation in macropores is crucial for Al dynamics, whereas in the planosol the temporal variation of the perched water table. Leachates from all O-horizons and upper mineral horizons as well as from the planosol subsoil are undersaturated with respect to the solubility of all mineral phases considered. With SI > O imogolite appears to be a permanently stable mineral in the subsoils of both podzol and cambisol. There is evidence for the Al(OH)₃ interlayer of Al-chlorites controlling Al dynamics in the subsoil of the podzol. Al(OH)SO₄ type minerals are not likely to regulate aqueous Al activities in any of the studied soils.     

Oberflächenverschlammung und Abflußbildung auf Böden aus Löß und pleistozänen Sedimenten

Surface sealing and runoff generation on soils derived from loess and pleistocene deposits An attempt is undertaken to bring together existing knowledge on the occurence of surface sealing, on subprocesses and factors controlling surface sealing, and on hydraulic properties of seals, with special reference to the soil conditions prevailing in Germany. A conceptional model is proposed that relates different subprocesses such as aggregate breakdown, aggregate deformation, particle rearrangement and different factors such as soil cover, microrelief, stone cover, and macropores to surface sealing and runoff generation. We conclude that loess soils and soils formed on pleistocene deposits are particularly prone to surface sealing, and seals formed on these soils can induce runoff at rainfall intensities of 5 mm h^?1.     

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.     

Ermittlung wirtschaftlich optimaler Phosphatgaben auf Löß- und Geschiebelehmböden auf Basis der CAL-Methode

Determination of Economical Optimum of Phosphate Fertilization on Loess and Loamy Soils 82 field trials with phosphate fertilizers on loess and loamy soils were evaluated to find out the economical optimum of fertilization. The evaluation in each trial was done by using the exponential function according to Mitscherlich with respect of profits and costs for yields and fertilizers. The result of this evaluation was, applied to the named soils, that the yield level has essential influence on the economical optimum of fertilization. Likewise the optimal P₂O₅ (CAL)-value in the soil is dependent on the yield level (CAL-value of group C), (Tab. 7). Accumulation of phosphate in soil caused by semi-liqued manure, magnesium content in soil, pH-value, and rainfall have a significant influence on the effect of mineral phosphate fertilization and on the reliability of prediction as well. Optimising resp. considering these factors and others are of supposition for exact evaluation of trials, for reasonable recommendation of both fertilization and threshold P₂O₅ (CAL)-value, and for critical examination of methods of soil analysis.     

Der Einfluß einer Kalkung auf Aggregatstabilität und Eindringwiderstand zweier Lößböden

Aggregate Stability and Penetration Resistance of two Normal and Limed Soils To investigate the meliorative effect of liming, the aggregate stability (determined by wet sieving and sedimentation) and the penetration resistance (by a previously described method (Becher 1973 a) of unlimed and limed samples of two field experiments on a Brown Earth-Pseudogley and a Humic Pseudogley were determined. Penetration resistance decreased with decreasing water suction, but it did not show significant relation to liming. Aggregate stability was increased by liming on the Brown Earth-Pseudogley but was lowered on the Humic Pseudogley, while penetration resistance was only influenced in some cases. The behaviour of the Humic Pseudogley was explained by its exceptional high organic matter content (5–6%).     

Effektive Durchwurzelungstiefe,Sickerwasserbildung und Nitratverlagerung in tiefgründigen Lößböden eines Trockengebietes

Effective rooting depth, percolation water, and nitrate leaching in deeply developed loess soils of a water‐shortage area In 14 deeply developed loess soils, high amounts of mineral nitrogen (N) were measured within the first meter, whereas several nitrate depth profiles up to more than three meters resulted in low and medium nitrate values. The maximum depth of water uptake was measured in two years on four representative sites with regard to soil and crop properties. The maximum depth of water uptake was always considerably deeper than 200 cm, with a maximum of 290 cm (alfalfa). It is assumed that roots take up nitrogen even in this depth. The calculation of the effective rooting depth resulted in noticeably higher values (for wheat between 160 cm and 185 cm) than those given by the ”︁German Instructions for Soil Mapping” (AG Boden, 1994), the ”︁Regulations of the German Organisation for Water Management and Land Improvement” (DVWK, 1995) or the ”︁German Institute for Standardization” (DIN, 1998). As a result of low annual precipitation (normally less than 600 mm), only a minor part of the high amounts of nitrate within the root zone was leached into deeper soil layers. We conclude that it is not possible to predict the potential groundwater pollution with nitrate on the basis of the mineral N content in the first meter of the soil profile.     

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.     

Eigenschaften,Entwicklung und Wert rekultivierter Böden aus Löß im Gebiet des Rheinischen Braunkohlen-Tagebaues

Conditions, genesis and value of recultivated loess soils Physical, chemical, microbiological and micromorphological investigations have been executed on recultivated loess soils deposited between 1963 and 1968 and under agriculture since than. The main results are: 1. Dry deposited materials are often strongly compressed at 50-120 cm depth. Wet and dry deposited materials may be compressed at 30-50 cm by tillage. 2. The new soils show already a notable carbonate metabolism, loss of sodium and magnesium and a certain enrichment of humus and potassium. 3. Well recultivated soils are forming fertile Pararendzina soils, whereas the other ones are developing into difficult Pseudogley soils. 4. Land evaluation gives values of 60 to 80. However, fertility is not as high, and 10-15 should be subtracted from the values. 5. In compressed soils, melioration by deep loosening and drainage is the only method to evoid further degradation. It is, however not free from difficulties.     

Pflanzenaufnahme und Extrahierbarkeit von lithogen,pedogen und anthropogen angereichertem Cadmium in einem Parabraunerde-Ap-Horizont aus Löß

Plant uptake and solubility of lithogeneous, pedogeneous and anthropogeneous cadmium of an Ap-horizon from Orthic Luvisol In a pot trial we investigated the cadmium uptake by ryegrass (Lolium multiflorum) and spinach (Spinacea oleracea) in soil material of an Ap-horizon from Orthic Luvisol consisting of loess contaminated with Cd lithogeneously (stone powder), pedogeneously (soil from Ah- and Bv-horizon) and anthropogeneously (CdO) respectively. The concentration of Cd in the pots was adjusted to 1.5. 3 and 6 mg/kg soil. The total Cd-charge in the soil being at the same level, the tested plants (ryegrass and spinach) took up at least two times more of Cd of anthropogeneous origin (CdO) than of the Cd of geogeneous (pedogeneous and lithogeneous) origins. A remarkably higher solubility of the anthropogeneous cadmium was noticed compared with Cd of geogeneous origin. The DTPA-solution showed these differences most clearly. The relative soluble part of the anthropogeneous Cd was more than 60% of the total content, whereas it was lower by the factor of 2 to 3 in the geogeneously enriched cadmium. In the 0, 1 M CaCl₂- and the acid (O.I M HCI + 0.125 M H₂SO₄)-extraction these differences were not as obvious. The DTPA soluble cadmium fraction and the Cd taken up by the plants tested showed the closest correlations.