The effect of different densities of Italian ryegrass (Lolium italicum L.: G₁- 5 kg/ha seeds, 60 cm row spacing; G₂- 5 kg/ha seeds, 20 cm row spacing; G₃- 20 kg/ha seeds, 60 cm row spacing, and G₄- 20 kg/ha seeds, 20 cm row spacing) and different rates of applied nitrogen fertilizer (N₁- 0 kg N/ha; N₂ - 50 kg N/ha; N₃- 100 kg N/ha and N₄-150 kg N/ha) on SPAD values under interaction between the crop and cleavers (Galium aparine L) was investigated.

This paper surveys sowing norms (row spacing and seed rate) in both our country and the world, as well as the optimal seed rates in grass seed production. It gives a short overview of row spacings and seed rates applied in our and some other countries. Earlier, grass cultivated for the purpose of seed production was grown on small vegetation area. According to some researches, high seed yields can be achieved by cultivating grass on large vegetation area.