Application of mineral and sideral fertilizers in different systems of basic tillage in sunflower cultivation

Comprehensive implementation of scientifically sound technological operations of sunflower cultivation, namely, rational methods of basic tillage, introduction of high–yielding zonal varieties and hybrids, scientifically sound fertilizer systems, is a way to increase its yield in modern agro–industrial complex. Establishing an optimal system of basic tillage for sunflower will help effectively destroy weeds, accumulate and retain as much moisture in the soil before sowing in the root layer as possible, mobilize nutrients, which will further provide the most comfortable conditions for growth and development of crops. Sunflower – a culture of intensive mineral nutrition, and therefore, the technology of its cultivation is demanding to the reserves of Nutrients in the soil, which can be replenished, both by applying nitrogen and phosphorus fertilizers and by green manure. This agricultural measure allows one to maximize the impact on the plant’s growth and development, which further affects the yield. The aim of our research was to determine the optimal combination of an effective system of basic tillage with the use of mineral and green manure fertilizers in the cultivation of sunflower hybrids. The research was conducted in 2019–2020 in the fields of the Institute of Oilseeds of NAAS. The soil of the experimental site – chernozem ordinary, medium–low low–humus, with a humus content in the arable layer up to 30 cm – 3.5%, available nitrogen – 7.2–8.5, mobile phosphorus – 9.6–10.3, mobile potassium – 15.2–16.9 mg/100 g of soil, pH of soil solution 6.5–7.0. Sowing of sunflower hybrids, such as Priority, Antonio, Nabir and Agronomic, was carried out with a row spacing of 70 cm and sowing rate – 50 thousand similar seeds per hectare. Main tillage systems: classical – disking in two tracks, plowing (PN–3–35) to a depth of 22–25 cm; minimum – disking in two tracks, cultivation (KPS–4,0) to a depth of 10–12 cm. Options for the use of mineral fertilizers: 1. Control – without fertilizers, 2. N40P60, 3. Sideral fertilizer (white mustard). Bookmarking of experiments and conducting research was conducted in accordance with generally accepted methods of field experiments in agriculture and crop production. In our experiments, white Zaporizhanka mustard was sown as a green manure crop in autumn after harvesting the predecessor (winter wheat). Under the weather conditions of the 2018 autumn, the dry biomass of mustard was 1.61 t/ha for the content of elements per dry matter: nitrogen – 1.34, phosphorus – 0.72, potassium 2.03%, which was equal to 21.5; 11.6; 32.7 kg per hectare respectively. Under arid conditions in the fall of 2019, only 0.48 t/ha of dry mustard biomass was obtained. The content of elements per 1 hectare was equal to: nitrogen – 6.5; phosphorus – 3.6; potassium – 9.6 kg. On average, for two years, the dry biomass of mustard was 1.05 t/ha, and the content of elements: 14.0; 7.6; 21.2 kg per 1 hectare respectively. As a result of monitoring the growth and development of sunflower plants, the influence of the main tillage systems and fertilizer options on the productivity of sunflower hybrids was established. Baskets of the largest diameter of sunflower hybrid plants Priority – 17.6, Antonio – 16.8, Nabir –17.2, Agronomic – 16.6 cm were formed during cultivation under the classical system of cultivation on the background of mineral fertilizers at a dose of N40P60. The average weight of 1000 seeds of sunflower hybrids were: under the classical system of basic tillage under control – 39.1–47.9, against the background of fertilizers at a dose of N40P60 – 40.6–49.4, against the background of green manure 40.0–48.4 g; it was lower with the minimum system of basic tillage. Under the influence of additional nutrition, the weight of 1000 seeds increased in both classical and minimal systems. The highest weights of 1000 seeds for all hybrids were noted in the classical system of basic tillage against the background of fertilizers at a dose of N40P60. On average, the husk of sunflower hybrid seeds was the lowest (23.2–31.4%) under the classical system of basic tillage against the background of N40P60 application. Based on the control (without fertilizers) and the background of green manure, the husk increased to 23.6–31.8 and 23.4–31.6%. With the cultivation of sunflower hybrids on the minimum system, seed husk increased by 0.1–0.4%. The most favorable conditions for the formation of productivity of sunflower plants have developed under the classical system of basic tillage, the yield of sunflower hybrids was: on control 1.82–1.98, on the background of mineral fertilizers 2.04–2.31, on the background of green manure 1,91–2.07 t/ha. Under the minimum system, the yield decreased by 0.13–0.25 t/ha and was in the range as follows: 1.67–1.83 on the control, 1.86–2.07 on the background of mineral fertilizers, 1.75 on the background of green manure – 1.90 t/ha. The increase from the application of mineral fertilizers was 0.12–0.33 t/ha, from green manure 0.05–0.12 t/ha. The highest yield of sunflower hybrids: Priority – 2.31, Antonio – 2.15, Nabir – 2.04 and Agronomic – 2.11 t/ha obtained by growing in the classical system of basic tillage with the application of mineral fertilizers at a dose of N40P60 for pre–sowing cultivation. The fat content in the seeds of sunflower hybrids was higher than in the classical tillage system and was in the range: 44.6–48.0%; under the minimum tillage system, its indicators decreased by 1.0–1.5% and amounted to 43.4–46.8%. The highest oil yield for all hybrids, 824–953 kg/ha, was obtained by the classical tillage system against the background of mineral fertilizers at a dose of N40P60.