named after academician M.Mirzaev, Doctor of Agricultural Sciences (DSc)

Аннотация

The article examines the accumulation of heavy metals in typical irrigated gray soils of the Piskent district of the Tashkent region and in the organs of fruit trees grown on these soils. It was found that the organs of fruit trees contain high concentrations of Zn, Pb, Cr, Cd elements. The content of mobile heavy metals in typical gray soils has the following decreasing order: Zn→Pb→Cu→Cd→Ni→Cr→Co. Key words: Soil, heavy metal, pollution, accumulation, peach, apple, leaf, fruit, seed, twig. INTRODUCTION. Heavy metals are mobile, moving through the soil profile and changing into a form more readily available for plant uptake [8; 1276-1280-p.], [10; 63-72-p.] Soils located close to industrialized areas survive and develop under the influence of natural soil-forming factors (climate, relief, parent rocks, soil flora and fauna, time), but technogenic factors affecting the soil lead to a deterioration of soil ecology [5; 27-32-p.], [6; 78-80-p.], [13; 36-44-p.], [4; 142-147-p.]. The chemical composition of plants is closely related to the elemental composition of the soil. Therefore, excessive accumulation of heavy metals in plants is primarily associated with their high concentration in the soil. Plants absorb mobile forms of heavy metals during their development, their amount being closely related to Выпуск журнала №-25 Часть–2_ Май –2025 198 MODERN EDUCATION AND DEVELOPMENT the presence of organic matter and the buffering capacity of the soil [7; 49-p.]. The accumulation of heavy metals in fruit trees in different concentrations depends on the ability of plant species to absorb elements and their differential accumulation in different organs [3; 306-310-p., 1; 157-168-p.]. Heavy metals accumulate in the surface layer of the soil without undergoing physicochemical or biological degradation, causing changes in soil properties, and over a long period of time accumulate in a mobile form that is absorbed by plant roots [12; 224-226-p.]. Many scientists have noted that the accumulation of heavy metals in plants varies depending on the tree species in nature. It has been found that the specificity of heavy metal accumulation to a tree species can be very clearly demonstrated in experiments. Because it has been found that the accumulation of heavy metals in some plant species is hundreds and thousands of times higher than the permissible limits [11; 131-p.], [2; 246–254-p.]. V.B.Ilyin found that some types of heavy metals (Fe, Cu, Zn, Mn, Mo) are necessary for plant metabolism in small concentrations, and if their amount exceeds a certain level, they become toxic, while some heavy metals (Pb, Cd, Hg) are considered metals that do not participate in plant metabolism, and they have a toxic effect on plants even at very low concentrations. [9; 150-151- p.]. MATERIALS AND METHODS. The research was conducted on typical gray soils and apple and peach tree stands in the Piskent district of Tashkent region. Determination of the amount of heavy metals in soil and plant samples was studied by the atomic absorption method in the laboratory equipment “Optical emission spectrometer AVIO-200” based on the method “Методические указания по определению тяжелых металлов в почвах сельхозугодий и продукции растениеводства” (1992). RESULTS AND DISCUSSION. The amount of mobile copper (Cu) in typical irrigated loamy soils in the Piskent district of the Tashkent region was found to be 16.37-13.79-15.79 mg/kg (sections 50-51-52) in the 0-30 cm layer, or 5.46-4.60-5.26 times higher than maximum allowable concentration (MPC), while in the 30-50 cm Выпуск журнала №-25 Часть–2_ Май –2025 199 MODERN EDUCATION AND DEVELOPMENT layer it was found to be 12.19-12.52-11.02 mg/kg, in the 50-80 cm layer it was found to be 8.24-9.33-8.26 mg/kg, and in the 80-100 cm layer it was found to be 3.33-2.37- 4.11 mg/kg. The amount of mobile copper in all soil layers was found to be above the permissible limit. It was observed that the amount of copper in the soil in a mobile form decreases from the arable layer of the soil (0-30 cm) to the lower layers. The amount of zinc in mobile form is 167.13-154.80-133.46 mg/kg in the 0-30 cm layer of the soil, 131.63-119.41-129.41 mg/kg in the 30-50 cm layer, 80.26-76.17- 69.67 mg/kg in the 50-80 cm layer, In the 80-100 cm layer, it is 41.37-32.36-29.25 mg/kg, and it was found that the amount of zinc in all studied soil layers is 1.27-7.27 times higher than maximum permissible concentration (MPC). It was found that the amount of elements of chromium, nickel, cobalt in irrigated typical gray soils is below the maximum allowable concentration (MPC). The accumulation of the chromium element in soil layers has been determined in the following concentrations: 3.56–4.00–4.69 mg/kg in the 0–30 cm layer; 2.42– 2.46–2.71 mg/kg in the 30–50 cm layer; 1.87–1.93–1.97 mg/kg in the 50–80 cm layer; and 1.20–1.29–1.54 mg/kg in the 80–100 cm layer. Pb was found to be 40.60-41.40-36.06 mg/kg or 6.77-6.90-6.01 times higher than the MPC in th