Initiale Marschbodenentwicklung aus brackigen Sedimenten des Dollarts an der südwestlichen Nordseeküste

Initial marsh soil development from brackish sediments The initial marsh soil development from brackish sediments was investigated in a transect from the tidal flat to the dike in the southeast Dollart (Lower Saxony, Germany). Oxidized morphological features increased from the tidal flat to the dike. Simultaneously the bulk density increased from 0.57 g cm^—3 to 1.12 g cm^—3 and the water content decreased from 78.8 % to 54.9 %. The soils closest to the tidal flat were massive, those closest to the dike had a crumble structure. The clay/carbonate ratio increased slightly from 3.3 to 4.8 in the same succession as well as the C/N ratio from 13.9 to 15.6. Likewise the salinity decreased from 7.8 ‰ to 1.5 ‰ and the dominance of Na was replaced by Ca within the pool of exchangeable and soluble cations. The data indicate initial processes of marsh soil development: structure forming, settlement, aeration, salt and lime loss, decomposition and changing ratios of adsorbed cations. Similar to marine developments the soils will enter the terrestrial phase as carbonate containing soils not characterized by the brackish sedimentation conditions. For the initial development of today old marshland soils (”︁Kleimarshes”) from brackish sediments, in contrast, it is likely, that they were already free of carbonate when entering the terrestrial phase. This is explained by long‐term reduction and oxidation of sulfur and low sedimentation rates.     

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.     

Niederschlags-Chemismus und atmosphärische Element-Deposition in einem an der Nordseeküste von Schleswig-Holstein gelegenen Agrarökosystem

Precipitation chemistry and atmospheric element-deposition in an agroecosystem at the North-Sea Coast of Schleswig-Holstein The objective of this study was to examine the chemistry of bulk precipitation and atmospheric element inputs in an arable soil near the North Sea coast of Schleswig-Holstein, North Germany. Bulk precipitation was collected at weekly intervals from November 1989 to October 1991. Precipitation amount, pH, electrical conductivity, and concentrations of Na⁺, K⁺, NH₄⁺, Mg²⁺, Ca²⁺, Cl^?, NO₃^?, and SO₄^2? were recorded. The average volume-weighted pH was 5.5 and the average EC was 92 μS cm^?1. Sodium and Cl^? were with 64% and 76% the dominant ions (equivalent concentration) in bulk precipitation indicating the influence of the North Sea. The contribution of marine alkalinity to neutralization reactions of bulk precipitation was negligible (1%). The neutralizing substances NH₃ (63%) and Carbonate (36%) were more important. Deposition rates were in 1990 and 1991 97.0 and 51.7 kg Na⁺ ha^?1, 6.2 and 4.0 kg K⁺ ha^?1, 15.0 and 8.4 kg Mg²⁺ ha^?1, 13.2 and 10.4 kg Ca²⁺ ha^?1, 12.3 and 9.5 kg NH₄⁺-N ha^?1, 8.0 and 5.9 kg NO₃^?-N ha^?1, 168 and 83.1 kg Cl^? ha^?1 and 19.1 and 12.7 kg SO₄^2?-S ha^?1. In 1990 both more westerly winds and stronger wind-forces occurred than in 1991 and resulted in higher inputs of marine origin. Calculated on Cl^? basis 93% of Na⁺, 55% of K⁺, 74% of Mg²⁺, 24% of Ca²⁺, and 36% of SO₄^2? were of marine origin. Atmospheric input of marine origin supplied 39–72% of Mg and 21–37% of S requirement for crop production. The North Sea is an important source providing significant amounts of these elements to agricultural crops.     

Morphologie und Alter von Böden der Südlichen Frankenalb und der nichtkarbonatische Mineralbestand der Kalksteine

Morphology and age of soils in the ‘Südliche Frankenalb’ and the noncarbonate mineral composition of the limestones Soils in the ‘Südliche Frankenalb’ are described according to their local particle size and color characteristics, and their typical situation in the landscape. ‘Solifluction’ (mixing of limestone fragments with terra fusca solum) and sedimentation of aeolian material were the important processes which complicate the reconstruction of soil formation. The quantities of carbonate-free residues of limestones vary in a wide range between 0.7 and 25.4%. With this property, a grain size- and a mineralogical property, the limestone samples are separated by discriminant analysis in three groups. In contrast, the clay mineral composition of all the limestone residues is very homogeneous. In the fine clay fraction (< 0.2 μm) and coarse clay fraction (2-0.2 μm) illite and illite/smectite mixed layer minerals are the predominant minerals with proportions of 90% and 80–85%, respectively. The time necessary for soil formation is calculated to be 1.6 (20 cm depth, IIT-horizon) and 2.7 million years (36 cm depth, IIT + Bv₂-horizon), respectively. This calculation is based on a Malm Delta limestone (0.7% residue). The carbonate output is calculated from CaCO₃ solution rates in the CO₂-H₂O system and actual leaching rates derived from local climate data. The period of soil formation from other limestones was not as long.     

Nährstoffgehalte von lössboden-toposequenzen in südniedersachsen und franken unter dem einfluss der bodenerosion

This paper deals with the effects of soil erosion on the horizontal and vertical distribution of nutrients in loess soil topo-sequences in southern Lower Saxony and Frankonia (W. Germany). Each topo-sequence consists of three parts: an upper plateau (or edge of a piedmont plain) with little soil erosion up to now, a slope which as a whole has been eroded very much, and a slope foot which is covered with colluvial sediments. Compared to the pure loess the soils contain more K, Na, and P, and less Ca. The distribution of the nutrients within the investigated topo-sequences is caracterized by high contents of potassium on the slopes, provided that the A₁-horizon is eroded, so that the B¹-horizon has come to the surface. Finally it is considered whether the erosion-made differentiation of nutrients has negative or positive consequences on the productiveness of the arable soils.     

Nitratabbau in tieferen Bodenschichten süddeutscher Ackerstandorte auf Löß

Denitrification in deeper soil layers of arable land in southern Germany This study deals with the attempt to determine nitrate losses by denitrification in deeper soil layers by means of balancing the nitrate and chloride contents in the depth profiles of repeatedly sampled locations on deep sediments derived from loess in southern Germany. The extent of the nitrate losses was dependent on nitrate concentration. In the intermediate vadose zone, high rales of denitrification up to 0.5 kg NO₃?N/(ha·d·0.33 m) were detected, if nitrate concentration was high. In no case complete denitrification occurred. The preconditions for denitrification in deeper soil was determined by the soil profile. Nitrate reduction was favoured by small proportions of aerated pores. Increased organic C contents derived from the layer of an interstadiale soil formation (Würm) and reduced sulfur in the Würm loess were found as reduced substrates for denitrification.     

Vertikaler Wasser- und Nitrattransport in tiefere Bodenschichten süddeutscher Ackerstandorte

Vertical water and nitrate movement into deeper soil layers on fields located in the south of Germany In Southern Bavaria, selected fields from deep loess and sandy sediments were sampled to a depth of maximum 10 m every 4 months, in order to determine the basic processes of water and nitrate movement in the course of the year. The downward movement of water and nitrate followed the principle of piston flow only in the intermediate vadose zone of loess soils with a leaching distance amounting 0.8 m per year. On the other hand, an accelerated as well as a delayed transport was observed in the zone of evapotranspiration of loess soils and in the whole profile of sandy soils, not being in accordance with the simple simulation model FLOTRA based on the classic theories of transport (Darcy flow, convection-dispersion-equation). Preferential flow led to the leaching of nitrate from the top soil to the lower boundary of the evapotranspiration zone of loess soils in 2 m depth, in winter and spring. In sandy soils nitrate was leached to the groundwater table in 4–6 m depth after extensive rainfall.     

Großräumige Bodenuntersuchungen auf Rieselfeldern südlich Berlin

Investigations of soils in the large sewage farm areas south of Berlin The sewage farms in the Berlin region represent very large contaminated areas for which new concepts for use have to be worked out. All potential users need informations about soil quality. It was the main medium for cleaning the sewage and therefore under “stress”. Investigations of the soil in this technologically influenced landscape have to be made in a specific way. Soil features, which are changed by sewage application, and aspects of the spatial soil pollution are described. Examples explain the dynamics of soil parameters after a discontinuation of sewage application.     

Untersuchungen über einige Böden in der Wüste des „Lut-e-Zangi Ahmed”︁ (Iran)

Investigations on some soils of the Lut-e-Zangi Ahmed desert, Iran ”?Lut-e-Zangi Ahmed”? is a part of the Lut desert, which is located in south-eastern Iran. The Lut desert is one of the warmest and driest deserts of the world. It is very poor in vegetation and water, particularly in useful water. The evaporation is nearly hundred times more than the precipitation during the year (Evap. = 5000), precip. = 50 mm/year. In the research of “Lut-e-Zangi Ahmed”-SW part of the Lut desert-where its soils were entirely unknown, it is tried to get information about the most important properties of the desert-soils and possibility of agricultural use, through the profiles and analyses. The average elevation of the “Lut-e-Zangi Ahmed” is 500 m above the sea-level. The region is very poor in vegetation. There are many large areas on which no vegetation exists. The only useful water (underground water) is found in this part of the Lut desert. There are different zonal-intrazonal and azonal soils in the “Lut-e-Zangi Ahmed” (compare Ganssen 1968) for example: Hamada-desert soils, grey and light-brown saline desert soils, fine textured alluvial soils and sand desert soils. The soils are salty (EC from 11-5 12 mmhos/cm) and neutral to weak alkaline. They are poor in organic matter, phosphor and nitrogen too. The predominating part of the area investigated is not suitable for agricultural use. Only 150 ha are arable land, because it is possible to get here suitable groundwater for desalinization and irrigation.     

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.     

Entwicklungen in der Ökologie der Bodenmikroorganismen—eine Übersicht

Developments in the ecology of soil microorganisms - a review In the ecology of soil microorganisms, much interest is focussed at present to the factors of soil microenvironment. The ability of solid particles to adsorb different microorganisms, their nutrients and metabolites is investigated. Furthermore, the macroecological factors, such as geographic locality, climate, soil temperature, moisture etc., which influence the distribution of different microorganisms in soils are considered. Microorganisms and their activity in soils of tropical and arctic regions are also investigated. Concerning the temperate zone, the extensive research of microbial ecology is continued, in order to maintain soil fertility and to solve different environmental problems.     

Einfluß der Konzentration der Huminsäuren auf ihre Fragmentierung in Alkalilösungen

The influence of concentration of humic acids on their fragmentation in alkaline solutions The fragmentation of synthetic and other four natural humic acids with accending concentrations in sodium hydroxide solutions would be examined. It was found that the fragmentation decreases with increase of concentration of the humic acids. A critical concentration at 0,2% is needed for the begin of retard reactions and the micell formation. The fragmentation of humic acids with high fragmentation rate will be less influenced by change of the concentration than those whose fragmentation rate are low.     

Beeinflussung der Assimilatspeicherungsprozesse in der Sommergerstenähre durch Kinetinbehandlungen

Effect of kinetin treatments on the accumulation of assimilates in the ears of spring barley Using individual plants of spring barley, cultivar Emir, during the grain-filling period the attempt was made to increase the production of assimilates and their storage in the ear by exactly timed and located application of kinetin solution. The production of assimilates in the flag leaf and their distribution were controlled by ¹⁴CO₂-labelling. The experiments showed the following results: 1. Treatments of the whole ear or the growing grain respectively with kinetin solution increased the ability of the ear to attract assimilates and increased the storage of assimilates, formed in the flag leaf. Moreover an increase in the assimilation rate of the flag leaf could be observed. 2. Treatments of the flag leaf blade with kinetin solution induced retention-effects of assimilates in this organ. After a temporary depression a distinct and continuous increase of the assimilation rate became apparent. 3. After treatments of the ear (resp. the grains) as well as after treatments of the flag leaf increasing yields were achieved as the result of increasing thousand-kernel-weights. The results are discussed under physiological and yielding aspects.