EFFICACY AND SELECTIVITY OF PENDIMETHALIN FOR WEED CONTROL IN SOYBEAN (GLYCINE MAX (L.) MERR.), GEZIRA STATE, SUDAN

Objective. The aim of the present study was to evaluate the efficacy and selectivity of the herbicide pendimethalin on weed control in soybean at Gezira State, Sudan. Methods. A field experiment was carried out at Gezira Research Station Farm, Wad Medani, Sudan during summer season 2018/2019. The pendimethalin (Pendimight 500 EC (R)) was applied at three doses as pre-emergence treatment. The doses were 1.339. 1.785 and 2.232 Kg a.i./ha. Weeded and un-wedded treatments were included for comparison. The treatments were arranged in a randomized complete block designed with four replicates. Data were subjected to descriptive analysis and analysis of variance procedure (P <= 0.05). Significant means were separated using Duncan's Multiple Range test. Results. The results showed that all herbicide treatments were effective in weed control. They significantly reduced weed infestation compared to un-weeded control and significantly promoted the yield and various growth characters of soybean over un-weeded control treatment, except pendimethalin at the dose of 2.232 Kg a.i./ha which only reduced the plant population by 7% due to a phytotoxicity effect on soybean as compared to un-weeded control treatment. Application of pendimethalin at the dose 1.339 kg a.i./ha significantly controlled grasses and broad leaf weeds in soybean. It was also found superior in respect of various growth and yield attributes. Highest seed yield (1562.5 kg /ha) was recorded under pendimethalin treatment at a dose of 1.339 kg a.i./ha. Chemical analysis of soybean seeds showed that no residues of the tested herbicide were detected. Conclusions. It is concluded that the tested pre-emergence herbicide pendimethalin at the dose of 1.339 kg could be used effectively and safely in controlling weeds in soybean crop.