Performance of oilseed rape in the Clearfield®-system in different cropping intensities

Abstract

A two-factorial field experiment should reveal the performance of Clearfield® oilseed rape under different cropping intensities. The experiment was conducted at the experimental station Ihinger Hof in 2014, with cropping intensity as factor 1 and herbicide strategy as factor 2, all treatments sown with variety PT228CL. Treatments of cropping intensities were “normal sowing” (NS; soil inversion tillage tillage, 50 seeds m-2, 12 cm row spacing), “reduced sowing density” (DS; soil inversion tillage, 25 seeds m-2, 25 cm row spacing) and striptill (ST; 25 seeds m-2, 25 cm row spacing). The two herbicide strategies were pre-emergence strategy (VAS; application of Colzor® Trio (30 g L-1 Clomazone, 187.5 g L-1 Dimethachlor, 187.5 g L-1 Napropamide) one day after sowing and of Agil® S (100 g/L Propaquizafop) 3.5 weeks after sowing) and Clearfield® strategy (CLS; application of Clearfield®-Vantiga® (375 g L-1 Metazachlor, 125 g L-1 Quinmerac, 6.25 g L-1 Imazamox) and Dash® E.C. (345 g L-1 fatty acid methyl ester, 205 g L-1 fatty alcohol alkoxylates, 46 g L-1 oleic acid) at the same day as Agil® S). NS resulted in the highest yield (3.9 t ha-1) which was significantly more than obtained by ST (3.6 t ha-1), the least-yielding intensity. There were no significant interactions of the effects. Weed density was highest in DS/CLS and ST/CLS with 12.8 and 13.9 plants m-2, respectively, and thus the two to threefold of the other treatments. The results indicate a lack of efficacy of Clearfield®-Vantiga® under the presumably higher weed pressure in DS and ST, specifically in controlling the weeds Stellaria media and volunteer cereals (in this case: Hordeum vulgare). An economic evaluation will follow.

Keywords

• Brassica napus
• imidazolinone tolerance
• pre-emergence herbicides
• soil tillage