Significant depletion of agricultural soils as a result of the intensification of
crop production has led to a 60-fold decrease in some plant nutrients, which need
to be restored through soil fertilisation.
Particularly noteworthy is the increased use of mineral fertilisers and new
chemicals, including desiccants, in the cultivation of crops, including sunflower,
which significantly increases the anthropogenic load on agricultural soils.In this
regard, there is a need for constant monitoring of the migration of toxicants,
including heavy metals and soils in the soil system – plant production for the
projected quality of produced products.
In this regard, there is a need for constant monitoring of the migration of
toxicants, in particular heavy metals and desiccants in the soil-plant system to
ensure the predictable quality of the products produced.
The research results revealed a certain influence of soil fertilisation on the
field germination of sunflower crops. In particular, when sowing 75,000
germinating sunflower seeds per hectare, the field germination rate was 86.7-
92.0%. The highest field germination of seeds was observed in the fertiliser
variants N45P90K45, N45P45K90 and N45P45K45 + liming, and the lowest in the control
variant without fertilisation.
Changes in the ratio of NPK fertilisers for sunflower cultivation also
affected its yield to some extent. Thus, when fertilising soils with N45P45K45, the
average yield of sunflower in 2022-2024 was 2.20 t/ha. A twofold increase in
6
ammonium nitrate in the variant (N90P45K45), double superphosphate (N45P90K45),
potassium chloride (N45P45K90) and in the variant (N90P90K90) resulted in an
increase in yield by 20.4%, 6.0%, 10.4% and 60.4%, respectively.
As a result of fertilisation of grey forest soil N45P45K45, the gross intake of
heavy metals was 20400.9 mg/ha due to a twofold increase in the rate of
application of ammonium nitrate (variant N90P45K45), double superphosphate
(variant N45P90K45) and potassium chloride (variant N45P45K90), and an increase in
the intake of these substances into the soil environment by 17.5%, 45.2% and
23.9%, respectively.
Our studies have established that the content of Pb and Cd in the vegetative
mass was 2.65 times and 2.1 times higher than the PL, while in sunflower seeds it
was 5.47 times and 9.0 times lower than the PL, respectively.
Sunflower flower nectar (bee pollen) products were found to contain 1.75
times less Pb, 7.85 times less Cd, 1.38 times less Zn and 1.47 times less Cu than
the permissible levels.
The nitrate content of sunflower seeds grown on grey forest soils was 32.2
mg/kg. The nitrate content in sunflower seed processing products did not exceed
the MRL, but was slightly different and amounted to: in meal – 24.5 mg/kg, which
was 23.9% less than the nitrate content in sunflower seeds, and in meal – 60.2
mg/kg, which was 46.5% more than in sunflower seeds.
The results of the research showed that at a yield of threshed sunflower
vegetative mass of 47 c/ha (in air-dry weight), 62040 mg of Pb, 1034 mg of Cd,
65800 mg of Zn and 41360 mg of Cu are removed from grey forest soil per
hectare.
At a sunflower seed yield of 21 c/ha, the removal of Pb – 182.7 mg/ha,
Cd – 231 mg/ha, Cu – 2625 mg/ha and Zn – 12810 mg/ha.
The removal of heavy metals by sunflower nectar (honey) from the soil was
2880 mg/ha, Cd – 180 mg/ha, Cu – 7440 mg/ha and Zn – 36840 mg/ha.
When analysing the intensity of heavy metal removal by sunflower pollen
from grey forest soil, it should be noted that Pb is removed from one hectare with
7
this product – 2565 mg/ha, Cd – 1215 mg/ha, Cu – 15300 mg/ha and Zn – 32400
mg/ha.
Regarding the gross removal of heavy metals by sunflower products
(vegetative mass, seeds, pollen, nectar) from grey forest soil, it should be noted
that this indicator was 11.83 g/ha for Pb and 1.56 g/ha for Cd, Zn – 108.2 g/ha and
Cu – 106.3 g/ha.
