Effectiveness of herbicides depending on moisture conditions and methods of soil cultivation.
The effect of various soil tillage methods and application of Baiyalan [molinate + propanil], Diamet-D [dimethylamine salts of dicamba + MCPA] or 2,4-D on weed control in the rotation fallow/wheat/wheat/maize/wheat/barley was studied in 1973-78. Weed infestation was greatest in maize, especially with min. tillage in the absence of autumn cultivation in dry years. In all the other crops wet conditions favoured weeds compared with dry years. Baiyalan was generally more effective than 2,4-D or Diamet-D, especially in wet years. Rotation yields depended more on moisture conditions than soil tillage methods. Systematic application of herbicides together with shallow soil cultivation stimulated weed spread, with Setaria viridis in dry years and Echinochloa crus-galli in wet years.