Search

1992 wurde zur Auslese des Siliziumvertexdetektors des ARGUS­-Experimentes am DORIS III-Speicherring (DESY) erstmals der VIKING-2­-Chip verwendet. Wegen des Strahlungsuntergrundes bei ARGUS wurden umfangreiche Untersuchungen unternommen, um die Strahlungsempfindlichkeit des VIKING-2­-Chips zu bestimmen. Die Testbestrahlungen wurden an einer Cs 137­-Quelle (E = 662kev) des DKFZ (Deutsches Krebsforschungszentrum) in Heidelberg duchgeführt. Insgesamt vier VIKING-2­-Chips wurden in zwei Bestrahlungsdurchläufen schrittweise bis zu 943 Gy(Si) bzw. 2021 Gy(Si) bestrahlt, wobei immer jeweils einer der Chips unter Spannung stand und die Anschlüsse eines zweiten mit Masse verbunden waren. Alle Chips waren am Ende der Bestrahlung noch voll funktionsfähig; die schwerwiegendste Veränderung bei Bestrahlung bestand in einer Zunahme des Rauschens. Mit einem speziell für ultrarauscharme Messungen ausgelegten Aufbau bestimmten wir die Zunahme der äquivalenten Rauschladung (ENC) in Abhängigkeit von der Lastkapazität C und der Dosis D bei einer Scheitelpunktszeit von 0,9 us. Der Zunahme des Rauschens entspricht eine Abnahme der Verstärkung v mit steigender Dosis. Durch Nachregeln der einstellenden Spannungen war eine Kompensierung von Strahlenschäden möglich; hierfür wird eine genaue Vorschrift angegeben.

Insgesamt sind die neuen Böden der Ruhrstädte durch zwei Merkmale gekennzeichnet, die in der ursprünglichen Lößlandschaft nicht zu finden waren. Es ist der hohe Steingehalt und der Gehalt an freiem Kalk der Böden. Die Böden der Lößlandschaft waren dagegen steinfrei und schwach sauer. Mit der Entstehung der Städte wandelte sich somit die Bodenlandschaft und bekam den Charakter von Mittelgebirgsböden. In der Forschung sind die Konsequenzen, besonders der Steingehalte, bisher kaum bearbeitet worden. Für ‚steinreiche‘ Städte gibt es in der Forschung noch viel zu tun.

Innerhalb der vorliegenden Doktorarbeit wurden die wesentlichen analogen Teile des CMOS Mixed-Signal Chips HELIX128S-2 entworfen und getestet; dieser Chip dient zur Auslese von Ladungssignalen aus Siliziumstreifen- und Gas-Mikrostreifen-Detektoren, die beim Nachweis von Elementarteilchen beim HERA-B Experiment (DESY, Hamburg) zum Einsatz kommen. HELIX128S-2 integriert 128 Verstärkerkanäle, bestehend aus einem schnellen (Anstiegszeit ca. 50 ns), rauscharmen (ENC = 474 e + 35 e/pF x Cin) Ladungsverstärker, der die Vorverstärkung der Strom/Ladungssignale (typisch 4 fC) übernimmt; die langsam abfallenden Vorverstärkersignale werden von einem nachfolgenden Pulsformer in zeitlimitierte Pulse (Abfallzeit

Geowissenschaften

Die Geowissenschaften

The aim of this paper was to interpret liming influence on soil fertility by different calculation model with variable importance of some soli properties. Liming and fertilization experiment was sat up in 20 L volume plastic pots with two types of acid soils with different texture from two different localities in order to collect data for calculation model. Ten mineral and organic fertilization treatments with two levels of liming were applied in four repetitions. Soil was sampled and analysed after first and second year of investigation in a year 2004 and 2005. Soil analyses included common methods used for soil fertility control. Results showed significant liming impact on increase of soil pH and phosphorus availability. In second year liming impacted on soil organic matter decomposition. Liming resulted with lower Fe, Mn, Zn and Cu availability in soils from both sites. Results of soil properties change influenced by lime application, mineral and organic fertilization were used to create calculation model. Selection of indicators for model assessment of liming impact on soil fertility included soil availability of P2O5 (mg kg-1 according to AL- method) , Fe, Mn, Zn, Cu (mg kg-1 EDTA available microelements) and soil organic matter content (SOM %). This soil indicators were quantified by application of score functions as mathematical overview of soil properties influence to soil fertility according to analysed range. Values of score functions ranged from 0 - 1 as optimum value. Indicator value was interpreted according to importance of certain soil property to soil fertility assessment. The calculation model consider variable importances (0, 25-0, 50) of three soil properties (AL-P, SOM and EDTA- microelements), but the summ of importances was in all cases set as 1, 00. Importance of AL-P, SOM and EDTA-microelements influenced very significantly on interpretation of liming and fertilization impact on soil fertility. The lowest importance of AL-P and SOM, and highest importance of microelements resulted in negative impact of liming (2-11%), neutral impact of liming+fertilization and positive impact of mineral fertilization without liming (6%) on soil fertility. Increasing importance of AL-P resulted in positive interpretation of liming+fertilization impact on soil fertility (15, 1%), as well as increasing importance of SOM (7, 6%). Simultaneously increasing importance of AL-P and SOM consequently decreased importance of microelements availability, and resulted in most positive intepretation of liming+fertilization impact on soil fertility (increasing 20, 8%).

Soil is a unique natural environment that contains enormous populations of bacteria, fungi, algae and protozoa. Microorganisms play a key role in the soil ecosystem functioning and their role is essentional in numerous soil processes, thus also in the nitrogen cycling process. Nitrogen is one of the most common limiting factors for the plant production. Therefore, mineral nitrogen fertilizers are widely used, since they contain nitrogen in the plant available form or readily transformable into this form. The aim of the present study was to determine the effect of soil covering and different nitrogen fertilizer rates on total number of bacteria and on microbiological processes involved in nitrogen cycling. For this purpose, a stationary field trial was set up on hydromeliorated terra rossa soil in Istria. Nine trial plots were formed, with three replications, which differed from one another in the amounts of nitrogen fertilizers applied (60 kg N/ha, 120 kg N/ha, 180 kg N/ha) as well as in soil surface covering (uncovered soil, straw covered soil and soil covered with black polyethylene film). Watermelon was used as the test crop. Sampling was carried out three times during the growing season - in the spring, summer and autumn periods. Effect of sampling season on total number of bacteria was determined. Highest values for the total number of bacteria were determined in the spring period. Also, in dependence on the season, different impacts of the studied trial factors upon total number of bacteria as well as on the abundance of free-living nitrogen fixers were determined. At the first sampling, different soil covering resulted in significant differences of data obtained. Statistically significant effect of mineral nitrogen application was determined at the second sampling as well, when the lowest values were obtained with the application of 60 kg N/ha. Significant effect of nitrogen fertilization upon the number of ammonifiers was determined in the spring period while this effect was less expressed in the summer and autumn periods. Values obtained for the abundance of nitrifiers and denitrifiers clearly indicate a downward trend from the spring to the autumn period. Soil covering with film resulted in the highest number of nitrifiers in all seasons. Application of different rates of nitrogen fertilizers had different effects on the abundance of both nitrifiers and denitrifiers, in dependence of the sampling season.

Fertilization with different amounts of mineral nitrogen (0 do 300 kg N /ha) have been applied continuously, from 1996 till 2006, in a stationary field experiment established on drained Pseudogley in Central Croatia. Trial treatments included annual fertilization with different mineral nitrogen rates, respectively with 0, 100, 150, 200, 250 and 300 kg N/ha. Analyses of total nitrogen and total carbon content in soil are presented for three investigated depths (0-30 cm, 30-55 cm and 55-80 cm), for soil samples taken three times during 2006 (April, July and December). Total nitrogen and carbon content were determined by dry combustion method (according to Dumas ; HRN ISO 13878:2004 for nitrogen and according to HRN ISO 10694:2004 for carbon). First soil samples were taken at 12th of April 2006, before second top dressing of winter wheat, second sampling was just after the harvest (17. July) and third sampling was at 18th of December. Differences in total nitrogen and carbon content have been noted after eleven years of fertilization, according to nitrogen rates and soil depths. Average content of total nitrogen in soil surface layer (0-30 cm) varied from 4489 to 8648 kg N/ha, in subsurface layer (30-55 cm) from 2226 to 7541 kg N/ha and in the next soil layer (55-80 cm) from 1713 to 4790 kg N/ha. Total Carbon content in soil varied between 0.235 % and 1.955 % and C/N ratio ranged between 2.1 and 10.8 depending on the time of sampling, depth and treatment.

The harmful elements monitoring, particularly cadmium (Cd), have become important for environmental protection. Cd toxicity is mainly induced by mimicking of zinc (Zn) in uptake and metabolism. As in some cases application of phosphorus (P) fertilizers are responsible for soil contamination with Cd, aim of this study was testing status of mobile fraction of Cd in soils following ameliorative P (PK) fertilization. Three stationary field experiments with increased rates of P (PK) application (monoammonium phosphate or MAP: 12% N + 52% P2O5, KCl containing 60% K2O, NPK 7:20:30) have been conducted in April of 2003 under conditions of continental Croatia at localities as follows: Okucani (the exp. I), Korenicani (the exp. II) and Maslenjaca (the exp. III). The experiments have been conducted by randomized block design in four replicates (basic plot, depending on the experiment, from 77.0 to 92.4 m2 ). The fertilizers were added on the usual fertilization (the control) and different amounts of nitrogen (N) added by MAP were equalized by CAN (calcium ammonium nitrate: 27% N + 2-3% MgO). For the next years only usual fertilization of the experiments were used. The fertilization treatments were as follows: control, 500, 1000 and 1500 kg P2O5/ha (the exp. I) ; control, 1250, 2500 and 3750 NPK/ha (the exp. II) ; control, P2O5 kg/ha = 250, 500, and 750, 500 kg K2O/ha, both 500 P2O5 and K2O kg/ ha (the exp. III). Soil sampling to 30 cm of depth was made by auger from each basic plot in October of 2005. Mobile Cd was extracted with NH4 Acetate + EDTA (pH 4.65) and its concentrations were determined using inductively coupled plasma (ICP). In general, amounts of Cd in soils were low (means 0.138, 0.082 and 0.131 mg Cd/kg, for the exp. I, II and III, respectively) and differences in soil Cd status among different fertilization treatments were non-significant (mg Cd/kg in the ranges from 0.132 to 0.140, from 0.077 to 0.091 and from 0.117 to 0.140, for I, II, and III, respectively).

Total 480 soil profiles covering an area of 31227 ha were analyzed for need of hydromelioration project in area of eastern part of Sava valley in Croatia. It is narrow belt longitude approximately 150 km and width form 5 to 10 km in west-eastern direction. Slobostina and Josava rivers are border toward west and east direction, respectively. Also, it is delimited by river Sava toward south and by Psunj, Pozeska gora and Dilj Mountains toward north. Aim of this study was testing available phosphorus (P) and potassium (K) status (Ammonium-Lactate-method) in surface (0-30 cm) soil layer of these soil profiles. P availability in about 30% of the tested agricultural land (9440 ha) is very low P (until 5 mg P2O5 100 g-1 of soil), next 32% (9897 ha) are in the range low P availability (from 5.1 to 10 mg), while only 17% (5445 ha) has good or very good P availability (above 20 mg). Especially a high frequency of low P availability was found in vertic gley, amphygley and hypogley soils (total 8680 ha or 28% tested agricultural land). Concerning the degree of K availability nearly one third of the tested area (9989 ha or 32%) is low supplied with K (less than 10 mg K2O/100 g of soil). Especially high frequency of this range of K availability is found in hypogley (4629 ha or near 50% of area covered by this soil type). The most favorable K status was found in semigley alluvial soils: only 7.7% of the area of this soil is moderate supplied with K and even 27.5% of the area is in range of very high K availability (above 25 mg K2O/100 g of soil). We recommend different amounts of ameliorative P and K fertilization every fifth year and ordinary fertilization every year. For example, the application of 1000 kg and 500 P2O5 either or K2O/ha for soil containing very low (less than 5 mg /100 g) and low nutrient levels (from 5.1 to 10.0 mg/100 g), respectively. For the remaining area we suggest P and K fertilization according these nutrients removal.