Manipulation of sunflower population density and herbicide rate for economical and sustainable weed management

Field study tested weed control efficacy, crop yield and economic return using various weed management strategies in sunflower growing with different population density. Treatments included four rates of PRE emergence application of S-metolachlor + fluchloridon and one POST emergence application of flumioxazin + quizalofop-pethyl. PRE-em application (1.4 + 2.4 and 1.2 + 2.0) provided at the higher crop densities (70 000) best weed control. However, PRE- em treatments with lower doses (0.8 + 1.6 and 1.0 + 1.8) and POST- em application did not maintain acceptable control of dominant weeds. Grain yield increased with the crop density, but did not statistically differ between applied herbicide treatments. Finally, the implication of this study demonstrated that sole application of tested herbicide treatments at higher crop sowing density (60 000 and 70 000) was found to be economically the best alternative strategy for reducing weed infestation and achieving a better yield.