Abstract only

Following the transfer of agrarian industry to market economy and establishment of provaid farms, application of mineral, especially phosphoric and potash, fertilizers, not produced domestically, becomes of significant importance. Absence of certification on radioactive nucleotide content leads to the fact that often along with the phosphoric fertilizers radioactive nukleotide of uranium-thorium dissociation are applied to the soil in quantities ten times exceeding their natural content (Aleksakhin, 1982). Intensity of accumulation of natural radioactive nukleotide in different organs of plants and in particular in maize depends on both natural and anthropogenic factors (Drichko, 1983). There are also data on the significant input of phosphoric fertilizers in accumulation of radioactive nukleotide in different types of soil in Georgia (Mgeladze, 1987). In 2002- 2003 field experiments, radiometric and laboratory agrochemical analysis were carried out with the aim to investigate the effect of different rates and optimal application patterns of mineral fertilizers on the intensity of accumulation of radioactive nukleotide in the field brown soils and different organs of maize plants. Radiometric measurements were conducted on multi-channel spectrometer "CANBERRA " under software support "Genie 2000". Based on the results of experiments we assume that in monitoring of accumulation of radioactive nukleotide not only the type, but also the original material of its production is to be considered. In our opinion the one of the most efficient tools for the control of accumulation of radioactive nukleotide in soil without decrease in crop yield of maize is row application of phosphoric fertilizers. The sanitary regulations on maximum allowed content of radioactive nukleotide in phosphoric fertilizers should also be reviewed, as establishment of sanitary regulations should be based on effective combined rates, instead of the individual one. (Popov, 1984 ). Taking into account that the so- called malignant "radiation" neoplasm makes up only 2% of background radiation, the established norms should vary depending on amount of used fertilizers and population (Ramzaev, 1996). Field experiments were carried out in 2003 at the experimental station of the institute in ZAHES settlement. Soil is meadow-brown. Average agrochemical characteristics measured: Ph in water suspension 7.3, in KCI extraction 6.4; humus content 2.3%, active phosphor at virgin lands 0.16%; hygroscopic hurnidity 2.89%; experimental maize variety Ajameti White. The scheme of experiment treatments were as follows: 1. Check (without fertilizers); 2. N 120K60 1 kg of active substance per 1 ha; 3. N120K60P 60; 4. N120K60P 90; 5. N12oK6oP120; 6. N120K6oPl20 7. N 120K60P 150 (phosphorus is applied in ro- ws unlike other 5 options) Average content in soil at the depth of maize root, as per specific activity: K4O -410 Bk/kg, U238 -28-31 Bk/kg and Th232 36-40 Bk/kg. Gamma- spectrometry of applied triple super phosphate was conducted and data was compared to radioactive nuclide content of simple super phosphate used in experiments in 2001. Specific activity of K40 in simple super phosphate exceeds that in triple super phosphate 4-5 times. The range of radioactive nukleotide of uranium-thorium dissociation is characterized with the diversity of separate radioactive nukleotide, but on the total their content is lower in triple super phosphate. Uranium, thorium and potassium approximate ratio is U :Th:K = 1:1.12:2.5. Radiometric analysis taken for the establishment of the rate of accumulation of radioactive nukleotide in different organs of maize plant ascertained that radioactive nukleotide of natural origin applied to the soil along with phosphoric fertilizers accumulate more in the side (stem, leaves, and ears) production parts of the maize plant than in com. This fact was confirmed also by other authors (Stasyev, 1986).

English

0409|AGRIS 0401|AL-Maize Program

Juan Carlos Mendieta

CIMMYT Publications Collection