Effect of the seeding and fertilization rates of cover crop and the seeding rate of timothy on the seed yield of the cultivar 'Tika'

In the years 2012–2015, the Estonian Crop Research Institute conducted a field trial in order to investigate the effect of the seeding and fertilizer rates of the cover crop barley 'Inari', and of the seeding rate of the timothy grass 'Tika' on the seed yield. In the trial there were four variants with the cover crop's seeding rate and nitrogen fertilizer rate, and three different seeding rates of timothy grass (3, 6 and 9 kg ha-1) were tested. The trial results indicated that both the seeding rate of the cover crop (variants 333 and 500 germinating seeds per m-2) and the nitrogen fertilizer rate (variants 60 and 90 kg N ha-1) had an effect on the later seed yield of the timothy grass. Thereat the effect of the cover crop’s seeding rate was smaller; the effect of nitrogen fertilizer bigger. The effect of the cover crop on the seed yield of timothy was bigger in the first year after establishment, in the following years the effect decreased. The highest timothy seed yield was obtained in the trial variant that was seeded with 3 kg of 100% pure live seeds (PLS) per hectare under the cover crop the seeding rate and nitrogen fertilizer rate of which had been reduced by one third. Economic calculations also indicated that in total of the year of establishment and three years of seed harvest, this variant turned out to be the most profitable one for the seed producer. The studied trial variants had no effect on the quality of timothy seed.