Abstract
This study presents the results of research on the impact of fine fraction zeolite from the Shankhanai deposit on the yield and quality of Samaladay tomato fruits cultivated in the dark chestnut soils of southeastern Kazakhstan during 2023–2024. It has been established that the use of zeolite helps to increase yields, improve product quality and increase profitability. The control group (no fertilizers) yielded 22.3 tons per hectare, while treatments with zeolite and fertilizers showed increased yields. The maximum yield increase of 6.7 tons per hectare was achieved with 2 tons of zeolite combined with N 90 P 90 K 90 fertilizers. Increasing fertilizer doses raised the dry matter content in tomato fruits from 4.93% in the control group to 5.46% with zeolite and double doses of mineral fertilizers, with a slight increase in sugar content. Mineral fertilizers increased nitrate levels in tomato fruits, ranging from 61 to 78 mg/kg compared to the control (68 mg/kg), while zeolite application reduced nitrate levels by 7 mg/kg relative to the control. The content of mobile forms of heavy metals (Zn, Cu, Cd, Pb) in the 0–20 cm soil layer under tomato cultivation in the control group was 2.50, 0.70, 1.20, and 0.40 mg/kg, respectively. Zeolite application contributed to the reduction of these levels due to its ability to bind heavy metals and decrease their availability to plants. The analysis showed that using zeolite in tomato cultivation on dark chestnut soils increased yield by 3.1 tons per hectare and provided a profitability of 64% due to low costs, whereas combining zeolite with mineral fertilizers increased yield by 5.7–6.7 tons per hectare but reduced profitability to 42%.