The influence of the ratio between nitrogen and potassium in winter wheat fertilization systems on its productivity and grain quality

Abstract

Purpose. To establish the optimal ratio between nitrogen and potassium in winter wheat fertilization systems and its effect on grain productivity and quality. Methods. The research is based on field experiments using the following methods: visual – to determine the phenological phases of growth and development of the crop; calculation – to determine the parameters of the crop structure and crop productivity; chemical – to determine the content of nutrients in the soil; mathematical and statistical – to assess the reliability of research results. Results. The use of mineral fertilizers for the cultivation of winter wheat contributed to the productive bushing of plants, the number of productive stems on fertilized variants exceeded the control (without fertilizers) by 37–97 pcs./m2 (7,7–20,1%), which ensured an increase in grain yield. On average, over the years of research, the application of potash fertilizers provided an additional grain yield of 0,49–0,84 t/ha (8,6–14,8%) on a nitrogen-phosphorus background N120Р70 and 0,38–0,75 t/ha (5,8–11,1%) – against the background of N180Р70. At the same time, the highest productivity indicators were obtained when applying N180Р70К120, where the yield was 7,31 t/ha. Fertilization of winter wheat contributed to the improvement of grain quality. According to three-year data, the content of protein in the grain increased from 11,5 to 13,4% in the fertilized variants compared to the indicator in the control – 9,4%, the content of crude gluten – from 20,5 to 25,2% (control – 13,0%). Conclusions. For the cultivation of winter wheat in the conditions of the Western Forest Steppe on a typical shallow, weakly humus light loamy chernozem with a low nitrogen, high phosphorus and medium potassium content, it was established that the highest grain yield in the experiment (7,31 t/ha) was provided by the introduction of N180Р70К120, the yield increase compared to the control (without fertilizers) was 3,15 t/ha, or 75,7%. The most acceptable ratio of nitrogen and potassium in the fertilization of winter wheat is 1: 0,66–0,75, for which the maximum increases in grain yield were obtained in the experiment compared to the backgrounds N120Р70 – background 1 and N180Р70 – background 2: for the introduction of N120Р70К90 – 0,84 t/ha (14,8%), for application of N180Р70К120 – 0,75 t/ha (11,1%), respectively. The use of mineral fertilizers contributed to the formation of food grains of winter wheat of the corresponding II-III quality class according to DSTU: 3768-2010.