Optimal growing regulations – guarantee of high productivity of sunflower
Authors: Nikitenko О.V. , Polyakov O.I. , Litoshko S.V. 
Published: January 2022

The level of sunflower productivity is determined by the conditions of soil nutrient regime in the growing area. Although the chernozems of the Steppe of Ukraine are quite rich in all macro- and microelements, but there are those that are in hard-to-reach forms, which complicates their assimilation by plants, so all agricultural techniques should be aimed at providing plants with available nutrients and moisture. Plant growth regulators, which are used to optimize crop nutrition during the main growing seasons , are becoming more widespread . Due to their use, the growth processes of sunflower plants are significantly improved and seed yield increases. Basic tillage is one of the effective measures for moisture accumulation and weed control. The aim of the research was to determine the optimal parameters of the system of basic tillage, the use of mineral fertilizers and growth regulators in the cultivation of sunflower hybrid Ratnik. The studies were conducted in 2016-2018 at the fields of the Institute of Oil Crops of the UAAS. The sowing was carried out at a depth of seed wrapping of 6-7 cm with a row spacing of 70 cm with a seeding rate of 50 thousand similar seeds per hectare. Basic tillage systems: classic – two-track disc, plowing (PN-3-35) to a depth of 22-25 cm; bottomless – two-track disc, endless tillage (KLD-3.0) to a depth of 25-27 cm; minimal – two-track discus, cultivation (KPS-4,0) to a depth of 10-12 cm. Mineral fertilizer application options: 1. Control – no fertilizer, 2. N40, 3. N40P60, 4. N60P60K60. Application options: 1. Control – treatment with water (250 l/ha), 2. Rost- concentrate + Oil gelatin (6-8 pairs of true leaves), 3. Forte gelatin + Mono boron gelatin (6-8 pairs of true leaves), 4. Mono boron chelate + Phosphate-potassium chelate (6-8 pairs of true leaves), 5. 1 treatment: Phosphate-potassium chelate + Multimix gelatin + Mono boron chelate (3-4 pairs of true leaves), 2 treatment: Mono gelatin boron (6-8 pairs of true leaves). The bookmarking of the experiments and the research were carried out in accordance with the common methods of field experiments in agriculture and crop production. The analysis of the data obtained as a result of research conducted in 2016-2018 showed that depending on the background of mineral nutrition and the option of using growth regulators for three systems of basic tillage, the conditions of moisture and weediness of Ratnik hybrid sunflower changed, which in turn affected on its performance. According to the average three-year indicators, the influence of agricultural methods on: the number of seeds and the weight of seeds from the basket, the weight of 1000 seeds. The largest number of seeds, the weight of seeds from one basket and the weight of 1000 seeds were observed against the background of fertilizer application at a dose of N60P60K60 in the classical system of basic tillage. Depending on the level of additional nutrition, the yield of Sunflower hybrid Ratnik was within an average of three years: under the classical system of basic tillage 2.62-3.46 t/ha; for dumpless 2.44-3.10 t/ha; at a minimum of 2.36-2.97 t/ha. During the cultivation of sunflower on the no-till and minimum systems of the main tillage, the yield decreased in relation to the classical one by 0.18-0.39 and 0.26-0.51 t/ha. The increase in yield from mineral fertilizers was: under the classical system of basic tillage 0.36-0.64 t/ha; for dumpless 0.25-0.51 t/ha; at a minimum of 0.24-0.45 t/ha. The largest increase was obtained by applying fertilizers at a dose of N60P60K60. The use of growth regulators in the cultivation of sunflower in all variants has led to an increase in yield: in the classical system of basic tillage by 0.13-0.32; for the dumpless – 0.08-0.25 and for the minimum – 0.09-0.25 t/ha. The most effective, other things being equal, was the use of a mixture of Rost-Concentrate + Chelatin oil. The highest yield of sunflower hybrid Warrior – 3.46 and 3.45 t/ha obtained by growing in the classical system of basic tillage, fertilizer application at a dose of N60P60K60 for pre-sowing cultivation and spraying crops with a mixture of drugs: Rost- concentrate + Chelatin oil (6-8 pairs of true leaves) and 1 treatment: Chelatin phosphorus-potassium + Chelatin multimix + Chelatin mono boron (3-4 pairs of true leaves), 2 treatment: Chelatin mono boron (6-8 pairs of true leaves). The number of weeds in sunflower crops varied depending on the method of basic tillage and almost did not change from the fertilizer option and was the lowest in the classical system, and air-dry weight of weeds changed both under the influence of the main tillage system and mineral nutrition . The highest total water consumption by harvest (286.2 and 286.3 mm), but the lowest water consumption ratio (832 m3/t) was observed in the classical system of basic tillage against the background of fertilizers at a dose of N60P60K60 with spraying sunflower crops a mixture of drugs Rost-concentrate + Chelatin oil (6-8 pairs of true leaves) and the first treatment: Chelatin phosphorus-potassium + Chelatin multimix + Chelatin mono boron (3-4 pairs of true leaves) and the second treatment: Chelatin mono boron pairs of true leaves). Yields were weakly correlated with growth regulators (r=0.17) and air-dry mass of weeds (r=-0.18), on average with the system of basic tillage (r=-0.66), the use of mineral fertilizers (r=0.61) and the number of weeds (r=0.53) and closely with the number of seeds (r=0.92), seed weight (r=0.97), weight of 1000 seeds (r=0.97), total water consumption (r=0.89) and water consumption ratio (r=-0.99).