Tillage practices affect weeds differently in monoculture vs. crop rotation

Reduced tillage practices are widely considered to be more sustainable than conventional practices, but many producers remain reluctant reduce due difficulties controlling weeds. Crop rotation is often put forward as the best means manage weeds in reduced systems, uncertainties around how different and crop rotations interact. Here, we assess effects of four on weed seedbank density composition wheat (Triticum aestivum) monoculture (WWWW), two rotations, wheat-medic-wheat-medic (annual medic, Medicago spp.; WMWM), wheat-canola-wheat-lupin (Brassica napus, Lupinus WCWL). We use data across a whole four-year period from long-term experiment replicated at sites South Africa’s winter rainfall region. The assessed follow gradient soil disturbance: (CT, inversion through ploughing), minimum (MT, shallow loosening), no (NT, direct drilling with tine openers) zero (ZT, disc openers). Our results indicate that type had effect within monoculture. Both generally lower densities dominance grass monoculture, under ZT seed bank both was similar found Thus antagonistic this system, possibly limited chemical control options CT, MT NT, or residue cover promoting establishment. Subsequently, recommend region seeking opt for NT rather ZT, avoid Weed researchers agronomists should wary other such interactions between management systems.