EFFECT OF TIMING AND DOSAGE OF “KAS 28” APPLICATION ON OAT PLANTS DEVELOPMENT

To determine the optimal options for using fertilizer “KAS 28” when growing hulled (covered) oat cv. ‘Kirovsky 2’, the following options were investigated: 1 – control (no fertilizer); 2 – “KAS 28” in the recommended dose (35 l/ha) at the tillering stage; 3 – crops treatment with “KAS 28” – 60 % of the recommended dose (21 l/ha) at the tillering stage; 4 – “KAS 28” in the recommended dose at the beginning of stem elongation stage; 5 – crops treatment with “KAS 28” – 60% of the recommended dose at the beginning of stem elongation stage. The studies were carried out in 2019-2020. Over the year of research, the average yield varied from 5.52 t/ha in option 3 (at control level) to 6.59 t/ha in option 5 (16.0 % over control). Variants 2 and 4 exceeded control by 0.49 and 0.50 t/ha (8.8 %), respectively. Treatment with a reduced dose of fertilizer in the tillering stage reduced yield by 0.65 t/ha (10.6 %), at the beginning of stem elongation stage, on the contrary, increased it by 0.41 t/ha (6.6 %). “KAS 28” application led to an increase in the panicle length by 3.5–5.3 % compared to control (16.9 cm), the number of grains per panicle by 5.3-12.0 % (48 pcs in the control variant), the grain weight per panicle by 5.6-23.4 % (control – 1.78 g). Generally, the application of a reduced dose of fertilizer was less efficient. However, fertilizer dose decrease led to a statistically significant increase in 1000-grain weight indicator (by 0.55–1.61 g or 1.4–4.1 %). To increase the yield of oat cv. ‘Kirovsky 2’ and reduce the anthropogenic load on the agroecosystem, we offer to carry out topdressing at the stem elongation stage with the fertilizer “KAS 28” at a dose of 21 l/ha.