INFLUENCE OF THE LONG-TERM FERTILIZING ON THE RADIOACTIVITY OF THE SOIL AND DIFFERENT DEGREE OF ADOPTING OF RADIONUCLEIDES FROM THE WHEAT AND CORN

GRUBISIC Mirko1, VULETIC Vedrana2, STOJANOVIC Mirjana1, STEVANOVIC Dragi3, PANTELIC Gordana2

1Institute for technology of nuclear and other raw materials, Belgrade, 86 Franchet d′Esperey 2 Institute of Occupational and Radiological Health "Dr Dragomir Karajovic", Belgrade 3 Faculty of Agriculture, University of Belgrade

Abstract

Technology processes which are application today in producing the phosphate fertilizers from the phosphate ores don't make possible isolating the uranium and following radionucleides, because over the 90% uranium from phosphate ores stays final products-in mineral fertilizers. In Serbia, by year on arable input about 1500t simplex fertilizers based on phosphates, and it is rating that in that quantities in the environment inputs about 30g of the uranium to hectare. In disintegrating the whole series of the 238U members of its series emit about 50 more intensively and characteristic gamma lines whit which we can get the data's about activity of the members of series. Such a quantity of radionucleides in the environment, pedosphere can important expose citizens to ionic rays and it can be important factor in rising the level of phone of radiation. Researches in this work need to give the answer in which measure application the mineral fertilizers, especially phosphate, contribute to contamination of the soil caused by long-term fertilizing (35 years) and differences of adopting from corn and wheat nursed in monoculture. The sample of non-carbonate smonitza are collected on the field which belongs to Centrum for agricultural and technology researches in Zajecar, East Serbia, after the 35 years monoculture experiment with wheat and corn in the variety without and with defined dose of mineral fertilizers (160kg N, 80 kg P2O5 and 80 kg K2O). Determination the activity of radionucleides, gamma spectrometry analysis, after the long term fertilizing on the examined smoniza is done especially for mentioned cultures for first three defined zones by depth (0-10, 10-20, 20-40 cm) of Ah-horizon. Like a control it is made determining activity of the radionucleides in the soil on the sample variety where wasn't fertilizing during the long-term experiment ant it is for wheat and corn. Based on that it is not given the accent only on chronic contaminating the soil by radionucleides and application the mineral fertilizers, already the transport, too, adopting in the system soil-different cultures. Based the measuring the activity 40K, 137Cs, 238U, 235U, 226Ra, 232Th, 212Pb are fortified the differences in the concentration of activity of radionucleides of the uranium series between the samples of smonitza non fertilized and fertilized in the long period. Destroying the natural balance of geochemistry relation of the uranium (238U) and radium (226Ra) increased especially in the samples of smonitza under the corn with which approved additional inputting U-238 in the soil. Enlarging the presence of the U-238 is noticed in the both treated cultures of the Ahp-horizon of smonitza (0-20cm) where is made ploughing of the mineral fertilizers for 5-6 Bq/kg under the wheat and 15-21 Bq/kg under the corn. The values of the activity of radioactive K–40 in smonitza in fertilized variety of wheat by depth increases while under the corn culture values decreases by depth and shows the differences of adopting of radionucleides from the root system of wheat and corn.

Key words: smonitza, radioactivity, fertilizing, phosphates, monoculture