The influence of nitrogen nutrition on the formation of the balance of nutrients in the agrocenosis of winter wheat

Abstract

Аim. To study the influence of doses and methods of applying nitrogen fertilizers on the peculiarities of the use and balance of nutrients in the agrocenosis of winter wheat and to form a paradigm of an ecologically balanced fertilization system on leached chernozem. Меthods. Short-term field and analytical. Results. For the first time, under the conditions of sufficient moisture in the Forest Steppe of Ukraine, for the cultivation of winter wheat on leached chernozem, a fertilization system that forms a balanced balance of nutrients in the soil and ensures a grain yield of more than 6.5 t/ha has been substantiated. It was established that with a biological harvest, winter wheat takes the most nitrogen from the soil at the ratio N:P:K = 2.7:1:1.9. It was found that the formation of a balanced nitrogen balance in the soil depended mainly on the doses of nitrogen fertilizers and did not depend on the methods of their application. The potassium balance significantly depended on the removal of straw from the field and the doses of potash fertilizers, the phosphorus balance – on the doses of phosphorus fertilizers. Conclusions. Nitrogen was removed by plants mainly as part of grain yield, potassium – as part of by-products. In the control without fertilizers, removal of nitrogen by grain (4.77 t/ha) was 94 kg/ha, phosphorus – 33, potassium – 25, straw (5.35 t / ha) – 26, 10 and 57 kg/ha, respectively. The most ecologically stable fertilization system was that anticipated leaving winter wheat straw on the field and applying mineral fertilizers in a dose of N110Р60K60, where 60 kg / ha of nitrogen as ammonium sulfate was applied on the frozen soil surface, 30 kg/ha as ammonium nitrate on the soil surface or as urea foliarly in the phase of emergence into the tube (IVth stage of organogenesis) and 20 kg/ha as urea foliarly in the phase of milk-wax maturity (VIIIth stage of organogenesis) on the background of P60K60 applied under deep plowing. Under such conditions, an almost balanced balance of nutrients was achieved in the soil with nitrogen deficiency – 20–22 kg/ha and the accumulation of phosphorus and potassium reserves in the amount of 14–15 and 24 kg/ha, respectively. Obtaining a grain yield of more than 6.5 t/ha based on sustainability requires the application of mineral fertilizers in the dose of N130Р50K40 and under the condition that winter wheat straw remains on the field. In the case of removal of straw from the field, a deficiency of nitrogen and potassium was formed in the soil in the amount of 62–64 and 63 kg/ha with a balanced phosphorus balance, which is evidence of an ecologically unstable fertilization system.