The Yield and Weed Infestation of Winter Oilseed Rape (Brassica napus L. ssp. oleifera Metzg) in Two Tillage Systems

Abstract

Results from a four-year field experiment were used to evaluate the effect of conventional tillage (CT) and no-tillage (NT) systems on the yield, selected yield and crop structure elements, weed infestation, and contents of fat and glucosinolates in the seeds of winter oilseed rape (Brassica napus L. ssp. oleifera Metzg). The study proved the beneficial effect of the NT system on the winter rape seed yield only during the precipitation shortage in the growing season. In the years with a sufficient sum of precipitation, a higher seed yield was produced in the CT than in the NT system. Considering the average values from the four-year study period, the seed yield and straw yield, plant density after emergence and before harvest, number of branches and main shoot length, and finally the 1000 seed weight were significantly higher in the CT compared with the NT system. In contrast, the NT system proved more beneficial regarding seed weight per silique and fat content of the seeds. The statistical analysis of the study results showed no effect of the tillage systems on the glucosinolate content of the seeds. In turn, a significantly higher number and air-dry weight of weeds as well as an increased density of Viola arvensis weeds were demonstrated in the NT plot compared with the CT plot of winter oilseed rape. Sonchus asper and Sonchus arvensis were identified in the NT plot but not in the CT plot. A significantly higher density of Chenopodium album and Euphorbia helioscopia weeds was detected in the CT system compared with the NT system. The statistical analysis of study results regarding weed community diversity showed similar values to the Shannon-Weinner diversity index (H’) in both tillage systems and a significantly higher value of the Simpson dominance index (SI) in the NT system compared with the CT system.