The effect of spring oilseed rape crop density on plant root biomass and soil enzymes activity

Abstract

Field experiment was carried out in 2011 at the Experimental Station of the Aleksandras Stulginskis University. The objective of this study was to establish the influence of spring oilseed rape (Brassica napus L.) crop density (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 plant root biomass and soil enzymes urease and saccharase activity. It was established that the dry biomass of spring oilseed rape roots was affected by crop density and soil layer. The highest dry biomass of spring rape roots was accumulated at the 0-10 cm soil layer. The root biomass at the 10-20 cm soil layer was found to be 8.2 to 13.2 times lower than that at the 0- 10 cm soil layer. The highest plant root biomass at the 0-10 and 10-20 cm soil layers was formed at a plant density of 100.1-150 plants m"2. With increasing rape crop density from 150.1 to 450 plants m"2, a trend of plant root biomass decrease was determined. With increasing rape crop density, compared with the thinnest crop, the activity of urease in the soil didn't change significantly. At a rape crop density of more than 100.1 plants m"2 the activity of saccharase significantly increased (by 30.7 to 53.3%) in comparison with saccharase activity in the thinnest crop.