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.     

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.     

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.     

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.     

Einfluß löslicher organischer Inhaltsstoffe auf die photometrische Analyse von Nitrat,Chlorid und Sulfat in Sickerwässern

Influence of DOC on the photometric analysis of nitrate, chloride and sulfate in seepage water Investigations on the applicability of photometric sulfate and chloride analysis in seepage water are showing strong influences by DOC, causing a raised detection of these anions. Interactions can be reduced, but not completely removed by solid phase extraction with reversed phase material. The photometric detection of nitrate is not influenced by DOC.     

Veränderung des Scher- und Kompressionsverhaltens von Ap-Horizont-Material aus Löß-Parabraunerden durch Kalkung

Change of shear resistance and compressibility of Ap-horizon material from loess-derived Parabraunerde Standardized artificial bodies prepared from soil material of a loessderived parabraunerde-Ap-horizon were tested with respect to their shear resistance and compressibility. The noncalcareous material was enriched with lime (2 stepts), soil humidity changed (3 steps) and the normal pressure increased (4 steps). Liming generally caused an increased initial shear resistance and led to a lowering of compressibility. The effect of lime is interpreted as an result of flocculation of the clay particles at the points of contact between silt grains in the soil matrix. The problems of transferring those results to the field are discussed.     

Modellversuche zur Phosphatsorption von Unterwasserböden unter oxidierenden und reduzierenden Bedingungen

Model experiments on phosphate Sorption by river sediments under oxidizing and reducing conditions. During intensive reduction by sodium dithionite, phosphate sorbing river sediments often show a pronounced desorption of phosphate. Reoxidation by air causes an increase in phosphate sorption up to five times the original value, the height being linearly related to the ferric oxide content (Fe_d) of the sample. A possible explanation for this phenomenon is the oxidative precipitation of iron(III) oxides with high surface area being very active in phosphate adsorption.     

Stoffbilanzierung in einer Pseudogley-Parabraunerde aus Löß unter Anwendung der IR-Phasenanalyse

Material balance in an aquic Hapludalf from loess by means of IR-phase analysis Grain size fractions of an aquic Hapludalf from loess near Göttingen were examined mineralogically and chemically. On the base of actual mineral composition (mode) by means of infrared spectroscopy weathering balances were made up. The results reveal a strong illite/mica loss of about 80 kg/m², which is due to decomposition in the A-horizon, and which is not compensated by a slight gain in the B-horizon. The mineral balance of the total profile yields a clay degradation of 44 kg/m². Furthermore, in the A-horizon the chemical balance gives evidence of considerable mobilizations and substantial losses mainly of SiO₂, Al₂O₃, MgO and K₂O combined in silicates. Depending on soil horizons and grain sizes the illites have K-contents varying from 4 to 8% K₂O. Al₂O₃ and MgO also show distinct variations. Both components are correlated negatively and decrease (Al₂O₃) respectively increase (MgO) from the top to the bottom.     

Veränderungen von Dreischicht-Tonmineralen durch natives K in holozänen Lößböden Mitteldeutschlands und Niederbayerns

Changes of three-layer clay minerals by native K in holocene loess derived soils of Central Germany and Lower Bavaria . Transformations of the clay minerals illite, vermiculite and smectite were determined in Central German (31 profiles) and Lower Bavarian loess districts (5 profiles) using 31–36 soil properties. To get significant differences between solum and sediment, the multivariate diskriminant analysis was applied. In the Central German loess district the following properties were crucial, to receive significant separation between solum-horizons and sediments: smectite content, several values of potassium fixation, interlattice potassium. Important were also some parameter of the K-Ca-exchange curve: Activity ratio \documentclass{article}\pagestyle{empty}\begin{document}$ \left({\frac{{{\rm aK}}}{{\sqrt {{\rm aCa}}}}} \right) $\end{document} of a soil solution in equilibrium with a soil (AR_o), buffering capacity of the soil for K at equilibrium (BCKE), labile K(K₁), exchange capacity of the exchange sites with a specific affinity for K minus labile K(EC_x—K₁). The differences of these values can be explained by assuming that (at pH 6–7) the beidellitic layers of smectites of the parent loess were transformed to illitic layers in the solum-horizons. In the Lower Bavarian loess landscape potassium fixation, total K in clay fraction (< 2 μm) and the parameters of the K-Ca-exchange curve indicate the same clay mineral transformation as in Central Germany. Smectite values were not introduced to the diskriminant function, because they were highly significantly correlated with potassium fixation. In this case potassium fixation has caused a better separation between the solum-horizons and the parent loess than X-ray data. From these results, from total -K of the fraction 2–20μm (solum-horizons smaller than sediments) and the vermiculite content fo the clay fraction, it can be concluded, that the rate of potassium release from micas and the rate of potassium fixation by beidellitic sheets during the Holocene period were nearly equal.     

Phosphat-Düngerbedarf von Getreide und Zuckerrüben im südniedersächsischen Lößgebiet

Phosphate fertilizer requirement of cereals and sugar beets on “loess soils” in the Southern part of Lower Saxony (F.R. of Germany) In the years 1984 to 1986 105 P-fertilizer experiments with winter wheat, winter barley and sugar beets were carried out on “loess soils” in the Southern part of Lower Saxony (F. R. of Germany). The mineral P fertilization applied as “Triplephosphat” varied between 0 and 250 kg P₂O₅/ha. Soil test values (P-H₂O method) of the sites ranged from 6 to 38 and were on the average 18 ± 8 mg P/kg. Besides the P-H₂O-extraction the following methods were used: CAL, DL, NaHCO₃ and EUF. In no case P-application increased yields of cereals and sugar beets, although in 1986 there was no P fertilization for three years. Results of plant analysis (0.3–0.6% P i. dm) also showed a sufficient P-status. Furthermore an increase of P content of soils (+20 mg P-H₂O/kg on average) by a fertilizer rate of 1500 kg P₂O₅/ha did not effect yield in the following years. Thus, on these fields with P levels of 5 mg P-H₂/kg soil (5 mg P₂O₅-CAL/100 g) and more a P fertilization corresponding to the P removal by the crop rotation of sugar beets and 2x cereals of about 180 kg P₂O₅/ha in three years is recommended, if crop residues remain on the field. At P levels higher than 12–14 mg P-H₂O/kg soil P fertilization can be below P-removal or omitted.     

Bodennutzung und Nitrat-Stickstoff in der Dränzone von Lößdecken der südlichen Niederrheinischen Bucht

Land use and nitrate-nitrogen in the vadose zone of loess deposits in the southern part of the Lower Rhenish Embayment Mean annual nitrogen-leaching was studied at seven experimental sites with grain-sugar beet crop rotation. Soil water simulation models and determination of the nitrogen content in the vadose zone below the rooting zone were combined to quantify the annual leaching rates. Leaching amounts to 11–18 kg NO₃^? N/ha · a at sites where only mineral fertilizer was applied, whereas sites with additional organic fertilizers show higher leaching rates of 30–36 kg NO₃^? N/ha · a.     

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.     

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.     

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.     

Beziehungen zwischen Bodenfruchtbarkeitskennziffern,Ertrag und Inhaltsstoffen von Zuckerrüben auf Löß-Schwarzerde

Relations between soil fertility parameters and sugar beet yield and quality characteristics respectively, on Haplic Chernozem soils In interpreting four “experiments without interference” (VoE) on a total of 435 plots the influence of soil fertility parameters (BFK_i) as organic matter, P, K, Mg, pH value, Cu, B and Mn on sugar beet yield and its nutrient contents on Haplic Chernozem sites under Ca immission has been analysed. “VoE” is a method applied to find specific field data by means of which relations within the multidimensional system soil - plant are ascertained by utilizing soil and yield parameter variations. With increasing pH value the nutrient contents in the soil decreased in the order the following sequence: Mn, Mg. Cu, B; and, resulting from that, the sugar beet yield decreased significantly. The coefficients of determination (B) of the triple linear regression between yield and BFK_i ranged from B = 0,21 to B = 0,33 and between nutrient contents and BFK_i from B = 0 to B = 0,41. Most of the regression functions contained “BFK_i boron” as a variable. It has been found that there were positive correlations between “BFK_i pH value” and “soluble ashes” and negative correlations between “BFK_i pH value” and P contents in sugar beet.     

Die Bestimmung von selektiv freisetzbarem Kalium in Parabraunerde aus Löß und Pelosol aus Gipskeuper-Tonmergeln

The determination of preferentially releasable potassium in hapludalf from loess and chromudert from gipskeuper clay marl Octadecylammonium-chloride (ODA)-extractable potassium and interlayer potassium (K_ZW), exchanged after thermal dissociation of adsorbed NH₄, were determined on particle size fractions of soils from gipskeuper clay marl (typic chromudert) and loess sediments (shallow hapludalf). The extraction by ODA is a diffusion controlled K-exchange process. This is shown by the increase of K-release at small sample quantity and K-concentration in the extraction solution. The ODA-potassium supplies (= Biotit-K) of the two typic chromudert were significantly higher than that of the shallow hapludalf (34000 and 30000 kg/ha vs. 22000 kg/ha, to a depth of 55 cm). Biotit-K was highest in the 2-6μm-fraction for both soils. The smaller the particle size, the larger were the amounts of K_ZW In the clay fractions of all samples they reached between 70 and 80% of total K (K_t). XRD-data give evidence of different mineral genesis processes between the two types of sediments. This is supported by the K_ZW-values of the particle-size fractions. The selectively releaseable interlayer potassium is associated with wedge shaped layers of illite. It can be differentiated from the bulk interlayer potassium by its preferential extractability in the first 3 to 5 heating treatments. This potassium quantity is, on an average, 22% of total clay interlayer potassium.