Weed suppression by increasing spring rape crop density
Lithuanian University of Agriculture, Studentu 11, Akademija, Kaunas district, LT-53067,Lithuania, e-mail: email@example.com, firstname.lastname@example.org
Field experiments were conducted in 2003 and 2004 at the Experimental Station of the Lithuanian University of Agriculture to study the influence of different spring rape (Brassica napus L.) densities (50.1–100, 100.1–150, 150.1–200, 200.1–250, 250.1–300, 300.1–350, 350.1–400, 400.1–450 plants m-2) on weed abundance. Increase of crop density and herewith increase of canopy should intensify the competition ability of spring rape plants and suppress weeds better. The results show that light intensity on the soil surface decreases when the assimilation area of spring rape leaves and total crop biomass increases. Weed density decreases when spring rape crop is densier. A significant negative relationship exists between weed biomass and spring rape leaf area index (LAI) (r = -0.62, P < 0.05), as well as between weed biomass and spring rape biomass (r = -0.67, P < 0.01). A significant positive correlation appears between weed abundance and light intensity on soil surface (r = 0.68, P < 0.01).