EFFECT OF ZEOL ACTIVATED ZEOLITE DOSES ON PRODUCTIVITY, QUALITY AND PHENOLOGY OF SUNFLOWER IN MIDDLE VOLGA REGION

Research was conducted to evaluate the effectiveness of using ZEOL activated zeolite for sunflower alongside mineral fertilizers to improve crop cultivation technology. The study was conducted from 2020 to 2022 on gray forest soils in the Republic of Tatarstan. The humus content of the soil in experimental plot was 3.0%, available phosphorus and potassium (according to Kirsanov) were 250 and 145 mg/kg, respectively. Soil pH was close to neutral (pH = 6.6). The experimental scheme involved studying the following options: zeolite at doses of 150, 350 and 500 kg/ha on the background of NPK based on planned yield of Avenzher sunflower hybrid of 2 t/ha. The background of mineral fertilizers served as a control. Use of zeolite increased field germination from 84.0% (control) by 1.8% at 500 kg/ha, sprout vigor by 0.05 g/plant (+27.8%) and decreased the angle of inclination of sunflower basket from 175° (control) to 140° (500 kg/ha), which reduces the risk of shattering and damage by birds. The diameter of baskets increased from 9.5 cm (control) to 11.9 cm at 350 kg/ha and weight of seeds per basket increased from 39.9 g to 49.4 g (+23.8%). Growing season was shortened by 4-6 days and seed moisture before harvest dropped to 6.2% (compared to 6.8% in the control). Average crop yield increased from 1.71 t/ha to 2.24 t/ha (+30.1%), demonstrating resilience: the increase was 44.4% (2.05 t/ha versus 1.42 t/ha) in the dry 2021. Seed oil content increased from 41.5% to 44.3-46.6%, with gross oil yield reaching 1,043.8 kg/ha (+47.1%). At the optimal dose of 350 kg/ha, yield increased by 0.51 t/ha (+29.8%), with a zeolite return on oilseeds of 1.46 kg/kg, oil yield of 983.5 kg/ha (+38.6%) and minimal expansion of the empty head area.