Enhancing Tribenuron‐Methyl Efficacy: The Role of Surfactants and Nitrogen

Adjuvants are widely employed to enhance herbicide performance, offering both economic and environmental benefits in weed management programmes. While most research has focused on surfactants, nitrogen‐based adjuvants, such as ammonium compounds, combined with herbicides like tribenuron‐methyl, also show promising potential. In a pot experiment conducted during 2021–2022, Sinapis arvensis (wild mustard) was used as the testing plant to evaluate the synergistic effects of various surfactants and ammonium sources, both individually and in combination, on the efficacy of tribenuron‐methyl. Treatments consisted of tribenuron‐methyl at 0, 0.3, 0.6 and 1.0 times the recommended rate (equivalent to 0, 4.5, 9 and 15 g a.i. ha −1 ), applied either alone or in combination with surfactants (castor oil ethoxylate [COE], lauryl alcohol ethoxylate [LAE], cocamidopropyl betaine [CPB] and sodium lauryl ether sulphate [SLES], all applied at 1 L ha −1 ) and ammonium sources (ammonium nitrate, ammonium sulphate and ammonium acetate, each at 1% [w/v], plus asparagine at 0.1% [w/v]). While surfactants and ammonium sources each independently enhanced herbicide efficiency, their combined application had a more pronounced effect, as evidenced by a greater number of treatments achieving significant reductions in effective doses. The simultaneous application of ammonium acetate with LAE or SLES reduced ED 90 to 6 g a.i. ha −1 . Additionally, compared to adjuvant‐free control, co‐applying asparagine amino acid with SLES or ammonium acetate with CPB lowered ED 90 values from 15 to 7.10 and 7.70 g a.i. ha −1 , respectively.