ECONOMIC REMOVAL AND NUTRIENT BALANCE OF DURUM WINTER WHEAT WITH LONG-TERM USE OF MINERAL FERTILIZERS

Abstract

Aim. To determine the economic removal and nutrient balance of durum winter wheat with long-term use of mineral fertilizers. Methods. Field, laboratory, calculationcomparative, analysis, statistical. Results. Significantly more nitrogen (84.6–135.0 kg/ha) is removed with grain harvest than phosphorus and potassium combined – 26.4–41.5 and 19.5–28.5 kg/ha, respectively. Judging by the paired combinations of the main nutrients, the application of nitrogen fertilizers increases the removal of nitrogen by grain by 49%, while phosphorus – by 32%, and potassium – by 28%. At the same time, the use of phosphorus fertilizers increased the removal of phosphorus by grain by 22%, and nitrogen and potassium by 8%. With a straw yield, winter wheat removes more potassium than nitrogen and phosphorus. With the introduction of complete mineral fertilizer (N150P60K80 variant), nitrogen, phosphorus, and potassium removal increased by 72%, respectively, compared to unfertilized plots; 41 and 95%. This indicates that durum wheat plants distribute phosphorus between grain and straw more efficiently than nitrogen and potassium. The application of nitrogen fertilizers at a dose of 150 kg/ha per year had the greatest effect on nitrogen economic removal, increasing it by 53.8–72.0 kg/ha, while phosphorus (P30–60) – by 9.6–15.3 and potassium fertilizers (K40–80) – by 2.2–5.6 kg/ha depending on the experiment variant. Nitrogen fertilizers also contributed to an increase in the economic removal of phosphorus by 9.1–11.3 kg/ha and potassium – by 17.6–23.6 kg/ha, depending on the experiment variant. The calculations showed that durum wheat straw is an important source in forming the nutrient balance in the soil. When it was removed from the field during harvest in all experiment variants, the balance of the main nutrients was negative, with the exception of phosphorus in P60K80 experiment variant, where it was positive (+ 6.6 kg/ha P2O5). Conclusions. The use of nitrogen fertilizers at a dose of 150 kg/ha per year has the greatest effect on the economic removal of nitrogen by durum winter wheat, increasing it by 53.8–72.0 kg/ha, while phosphorus (P30–60) – by 9.6 –15.3 and potassium fertilizers (K40–80) – by 2.2–5.6 kg/ha depending on the experiment variant. Nitrogen fertilizers also contribute to an increase in the removal of phosphorus by 9.1–11.3 kg/ha and potassium by 17.6–23.6 kg/ha, depending on the experiment variant. Under the condition of leaving the straw yield of durum winter wheat on the field for fertilizer and applying nitrogen fertilizers at a dose of 150 kg/ha per year, the nitrogen balance is positive – +15.0...28.4 kg/ha depending on the experiment variant. A positive balance of phosphorus with an indicator of +18.5 kg/ha in N150P60K80 experiment variant ensures the application of phosphorus fertilizers at a dose of 60 kg/ha per year, while potassium – + 12.8 kg/ha in N150P60K40 variant.