125
beet > cucumbers > tomatoes. AC of
238
U for fodder crops increases in the following
order: corn (for silage) > vegetative mass of peas > alfalfa (hay) > Sudan grass
(hay).
It is known that in addition to specific features, the variety of crops influences the
transfer of
238
U into plants. For example, the difference in the content of
238
U in
spring wheat straw grown on typical sierozem, depending on the variety, was 2.5
times, and in grain, it was 2.4 times (Butnik et al. 1989).
The main factor affecting the uranium transfer from the soil to the plants is the
agrochemical properties and humidity of contaminated soils. The type, hydromorphic feature and acidity of the soil medium significantly affect the plant uptake of
238
U from the soil. The transfer of
238
U from hydromorphic peat soil into the vegetation of the same species is more intensive than from automorphic sod-podzolic soil.
This is evidenced by higher transfer factors of
238
U into corn grain from peat soil
than from sod-podzolic soils. More intensive accumulation of
238
U from peat soil is
also facilitated by its higher acidity (pH KCl 5.8) compared to sod-podzolic soil (pH KCl
7.3) (Sokolik et al. 2013).
Our investigations under conditions of greenhouse experiments on two soil types
(seven soil differences) showed that the accumulation of
238
U in the yield of oats,
barley, spring wheat and peas depends on agrochemical characteristics of soils. The
AC of
238
U in the grain of oats is (1.5−4.1) × 10
−3
and in straw (9.4−25.0) × 10
−3
.
The AC of
238
U in the pea grain is (0.8−3.3) × 10
−3
and in its straw (7.1−18.3) × 10
−3
.
The accumulation of
238
U by the grain of spring wheat and barley on leached chernozem is 3.7–4.4 times lower than on sod-podzolic sandy loam soil. Not all properties of soils equally influenced the rate of
238
U accumulation in the crops. The closest
inverse relationship was found between the accumulation of a radionuclide in the
grain and the content of humus in the soil. The correlation coefficient between the
accumulation of
238
U in the oats grain and the humus content in the soil was
R = 0.91 ± 0.004. Soils rich in humus and containing a significant amount of Ca
2+
ions in soil absorbing complexes (SAC) have a maximum absorption capacity and
are characterised by a heavier granulometric composition. The solid phase of such
soils absorbs radionuclides, and a smaller proportion of them pass into plants in
comparison with soils, which have lower fertility (Ratnikov et al. 2007).
Under the greenhouse experiment conditions for five types of soils, the ACs of
238
U for barley varied up to eight times, depending on the soil agrochemical properties. With an increase in the humus content in the soil, exchangeable calcium and the
reaction of the soil solution became neutral, and the ACs of natural radionuclides
decreased in most cases. The relationship between the AC of natural radionuclides
in barley plants and the indicated soil properties in most cases was statistically significant and could be described by equations of curvilinear regression calculated on
the basis of experimental data (Arkhipov et al. 1984).
Depending on the agrochemical, physical and chemical properties of the soils of
the North Caucasus, the accumulation coefficient of uranium by pea grain varied
within the limits of (10−181) × 10
−4
, and by the vegetative mass, it varied within
(9−134) × 10
−3
. The mobility of uranium in soils and the soil-plant system changed
during the transition from acidic soils to neutral and slightly alkaline soils.
The Behaviour of Uranium in Soils and the Mechanisms of Its Accumulation…
beet > cucumbers > tomatoes. AC of
238
U for fodder crops increases in the following
order: corn (for silage) > vegetative mass of peas > alfalfa (hay) > Sudan grass
(hay).
It is known that in addition to specific features, the variety of crops influences the
transfer of
238
U into plants. For example, the difference in the content of
238
U in
spring wheat straw grown on typical sierozem, depending on the variety, was 2.5
times, and in grain, it was 2.4 times (Butnik et al. 1989).
The main factor affecting the uranium transfer from the soil to the plants is the
agrochemical properties and humidity of contaminated soils. The type, hydromorphic feature and acidity of the soil medium significantly affect the plant uptake of
238
U from the soil. The transfer of
238
U from hydromorphic peat soil into the vegetation of the same species is more intensive than from automorphic sod-podzolic soil.
This is evidenced by higher transfer factors of
238
U into corn grain from peat soil
than from sod-podzolic soils. More intensive accumulation of
238
U from peat soil is
also facilitated by its higher acidity (pH KCl 5.8) compared to sod-podzolic soil (pH KCl
7.3) (Sokolik et al. 2013).
Our investigations under conditions of greenhouse experiments on two soil types
(seven soil differences) showed that the accumulation of
238
U in the yield of oats,
barley, spring wheat and peas depends on agrochemical characteristics of soils. The
AC of
238
U in the grain of oats is (1.5−4.1) × 10
−3
and in straw (9.4−25.0) × 10
−3
.
The AC of
238
U in the pea grain is (0.8−3.3) × 10
−3
and in its straw (7.1−18.3) × 10
−3
.
The accumulation of
238
U by the grain of spring wheat and barley on leached chernozem is 3.7–4.4 times lower than on sod-podzolic sandy loam soil. Not all properties of soils equally influenced the rate of
238
U accumulation in the crops. The closest
inverse relationship was found between the accumulation of a radionuclide in the
grain and the content of humus in the soil. The correlation coefficient between the
accumulation of
238
U in the oats grain and the humus content in the soil was
R = 0.91 ± 0.004. Soils rich in humus and containing a significant amount of Ca
2+
ions in soil absorbing complexes (SAC) have a maximum absorption capacity and
are characterised by a heavier granulometric composition. The solid phase of such
soils absorbs radionuclides, and a smaller proportion of them pass into plants in
comparison with soils, which have lower fertility (Ratnikov et al. 2007).
Under the greenhouse experiment conditions for five types of soils, the ACs of
238
U for barley varied up to eight times, depending on the soil agrochemical properties. With an increase in the humus content in the soil, exchangeable calcium and the
reaction of the soil solution became neutral, and the ACs of natural radionuclides
decreased in most cases. The relationship between the AC of natural radionuclides
in barley plants and the indicated soil properties in most cases was statistically significant and could be described by equations of curvilinear regression calculated on
the basis of experimental data (Arkhipov et al. 1984).
Depending on the agrochemical, physical and chemical properties of the soils of
the North Caucasus, the accumulation coefficient of uranium by pea grain varied
within the limits of (10−181) × 10
−4
, and by the vegetative mass, it varied within
(9−134) × 10
−3
. The mobility of uranium in soils and the soil-plant system changed
during the transition from acidic soils to neutral and slightly alkaline soils.
The Behaviour of Uranium in Soils and the Mechanisms of Its Accumulation…