Imre Kádár

Long-term effects of heavy metals and microelements on nematode assemblage.

Effects of Cd, Cr, Se and Zn at a maximum rate of 270 mg kg(-1) were studied on a nematode assemblage after 6-10 years of application. Winter wheat, sunflower, sorrel, barley and rape were grown on the experimental field. Cd had a moderate effect on nematodes in spite of the fact that this element significantly decreased plant biomass. Cr was harmful to plants only in the first year of the study. However, Cr decreased Aporcelaimellus density and maturity index, increased Pratylenchus density and bacterial-fungal ratio, changed the c-p structure and feeding type composition. Se proved to be very toxic at a concentration of 11 mg kg(-1) (NH(4)-acetate+EDTA soluble form). Some advantageous effects of Zn were found in the first year. These disappeared later on. Remarkable between-year fluctuations of the nematode assemblage composition were observed.

Electrostatic spectrometer for measurement of internal conversion electrons in the 0.1–20 keV region

Abstract A new second order focusing, n = 1.5 cylindrical mirror electron spectrometer has been built. It enables us to measure the electrons emitted from the radioactive sources in the 0.1–20 keV region with an instrumental energy resolution of 0.1-1%. The ring-shaped input slit serving as a virtual electron optical object together with the large dimensions of the analyser (the total focal length equals 525 mm) allow us to utilize sources up to 1.5 cm 2 area. The spectrometer was adjusted using electron guns and tested also by 57 Co and 169 Yb radioactive sources prepared by vacuum evaporation and mass separation. The instrument operates automatically at oil-free vacuum of 4 × 10 −6 Pa and the electron spectra are scanned in cycles. The background of the channeltron is about 1.5 counts/min.

A simple theoretical approach to multiple ionization and its application for 5.1 and 5.5 MeV/u Xq++ Ne collisions

The simple geometrical model we developed recently for ionization probabilities on the basis of a geometrical BEA picture is generalized and extended to take into account magnetic substates and non-zero impact parameter ion-atom collisions. Ionization probabilities per electron for the L shell and separately for the 2s and 2p Subshells of neon in 5.1 MeV/u N+ and N7+ as well as 5.5 MeV/u H+ collisions were determined from 0.8−1 eV resolution K-Auger spectra. Anisotropy parameters of KL-LL23L23 satellite lines were determined in 5.5 MeV/u Ar6+, Ne10+ and 5.1 MeV/u N2+ collisions. The comparison of the extended model with the experimental data shows a good agreement. The model seems to be able to give account of the dependence of the ionization probability on quantum numbers l and m. Comparing the results with a wide range of experimental data no contradictions were found with the universal scaling features predicted by the model. By analyzing the impact parameter dependence of ionization probabilities the validity of the model was estimated to break down at ν1 ≈ ν2/3 towards lower impact velocities.

Leaching of microelement contaminants: a long-term field study.

Abstract A field experiment with microelement loads was set up on loamy textured, calcareous chernozem soil formed on loess. The ploughed layer contained ca. 5% CaCO3 and 3% humus. The soil was well supplied with Ca, Mg, Mn and Cu, moderately supplied with N and K, and weakly supplied with P and Zn. The water table is at the depth of 15 m, the water balance of the area is negative, and the site is drought sensitive. Salts of the 13 examined microelements were applied at 4 doses in the spring of 1991. Treatments were arranged in a split-plot design, in a total of 104 plots with two replications. Loading rates were 0, 90, 270 and 810 kg/ha per element in the form of AlCl3, NaAsO2, BaCl2, CdSO4, K2CrO4, CuSO4, HgCl2, (NH4)6Mo7O24, NiSO4, Pb(NO3)2, Na2SeO3, SrSO4, ZnSO4. Soil profiles of the control and the 810 kg/ha treated plots were sampled in the 3rd, 6th and 10th year of the trial. The mixed samples, consisting of 5 cores/plot were taken in 30 cm steps to 60 cm (year 1993), 90 cm (year 1996), and 290 cm (year 2000). Ammonium acetate + EDTA-soluble element content was determined. The main conclusions of the study are: 1. In soils contaminated with 810 kg/ha load rates As, Hg, Ni, Cu, Pb, Ba and Sr displayed no significant vertical movement. There is little uptake and translocation in plants of these elements: their concentration in the above-ground plant parts usually remains below 5D 10 mg/kg dry mass with the exception of Ba and Sr showing a somewhat higher accumulation. Under our conditions the above elements did not behave as dangerous contaminants to the soil, groundwater, or plants. 2. Moderate leaching of Zn and Cd was detected when applied at higher doses. Their accumulation was also moderate in the above-ground plants parts. Zn is not a dangerous pollutant for soil, plants or groundwater at our site. Cd, however, is a very dangerous element because of its high toxicity to mammals, soil life and crops. 3. Cr, Se, and Mo (in the form of chromate, selenate and molybdenate anions) exhibited great mobility in the soil and partly in the soil-plant system. Cr was hardly detectable in the above-ground parts of plants. Still, its rapid leaching can jeopardize groundwater quality. Se was strongly accumulated in all plant organs and was highly toxic for all crops. Mo, too, showed 2D3 orders of magnitude greater accumulation in plant parts, resulting in products unfit for animal or human consumption. Under our experimental conditions Cr(VI), Se, Mo can be classified as dangerous contaminants, since the anion forms remained stabile for a long time in this well-aerated calcareous environment.

Sustainability of soil fertility nutrient levels

Introduction In comparison to other plant nutrients the mobility of P in soil is low because of the generally low solubility of phosphate compounds and the strong P-binding capacity of soil components. On the other hand, residual effect of previous P application is more long lasting than that of potassium, and especially than that of nitrogen. For providing the P requirement of crops, soils need a sufficient pool of plant-available P (Fuleky, 2006; Sardy et al., 2006; Ragalyi es Kadar, 2006; Marton, 2006; Csatho et al., 2006; Rekasi es Filep, 2006). Table 1. Nutrient balances in Hungarian Agriculure, kg/ha (Agricultural area, 1900-2000) Turnover 1900-5

A reliability test of measured spectra

Abstract A mathematical procedure is suggested to verify the constancy of the measurement conditions and the measuring apparatus, respectively. The derived quantities are statistical variables of a normal distribution, so quantitative criteria can be given to determine the goodness of the measurement and apparatus. They also help to decide if systematic errors are present during the measurement and also allow to test if the estimated error of the measured data is correct. The proposed method has been tested on spectra measured by the electrostatic electron spectrometer ESA-21 [1].

TheKLL Auger spectrum of manganese

AbstractTheKLL Auger electrons of manganese (Z=25) emitted in the55Fe decay were measured using an electrostatic spectrometer. The computer analysis of the spectra yielded the following intensity ratios:

Genotype and liming effects on cadmium concentration in maize (Zea mays L.)

\begin{gathered} KL_1 L_1 :KL_1 L_2 :KL_1 L_3 :KL_2 L_2 :KL_2 L_3 :KL_3 L_3 \hfill \\ = (0.13 \pm 0.06):(0.31 \pm 0.02):(0.11 \pm 0.01) \hfill \\ :(0.11 \pm 0.03):(1 \pm 0.05):(0.07 \pm 0.05). \hfill \\ \end{gathered}