TOTAL PROTEIN CONTENT IN GRAIN AND GROSS PROTEIN YIELD WITH GRAIN CROP UNDER DIFFERENT FERTILIZER APPLICATION SCHEMES FOR WINTER RYE (SECALE CEREALE L.)

Efficient use of soil nitrogen by winter rye presumably requires a source of readily available potassium, especially in the spring tillering phase. The aim of research was to study the protein content in winter rye grain and the gross protein yield with grain crop under different ammonium and potassium nitrate application schemes to improve the fertilizer application system for the crop. The work was carried out in 2019-2021 in Leningrad region on winter rye plants of Evrika variety. The soil is sod-podzolic loamy. Humus content was 2.0…2.3%, pH of salt extract was 5.2…5.5, content of available mineral nitrogen was 12…15 mg/kg, available potassium and phosphorus (according to Kirsanov) were 80…100 mg/kg and 180…200 mg/kg respectively. The fertilizer rate applied during the growing season was 0 (control), 30, 60 or 90 kg/ha for the active substance nitrogen. At each fertilizer rate, the effect of the presence or absence of potassium (factor A), as well as the methods and timing of fertilizer application (factor B - fractional in autumn and spring with potassium, fractional without potassium, one-time in spring with potassium, one-time without potassium) were studied. The total protein content in grain varied from 9.29 to 12.30% of absolutely dry matter and was practically independent of the amount, type and timing of fertilizer application, but was determined by the weather conditions of the year. The gross protein yield varied from 136.6 to 462.5 kg/ha and was directly determined by the crop yield (the correlation coefficient was 0.97...0.99), with the highest gross protein yield (150...195% of the control) noted in the variants with potassium nitrate in each year.