Effects of Herbicide Haloxifhop-R-methyl ester application and surfactant on grass weeds control, Safflower yield and yield components

A field experiment was conducted to evaluate the effect of varying doses of haloxifhope-R-methyl ester herbicide on grass weeds grown at various stages in 2011-2012 growing season in Research Farm of College of Agriculture, Shiraz University. The study was carried out as split split plot based on randomized complete block design with three replicates. Treatments were haloxifhope-R-methyl ester herbicide doses (0.6, 0.8 and 1.0 L/ ha) as main factor, surfactant (with and without) as sub factor and time of herbicide application (2 leaf, 6 leaf and tillering of grass weeds) as sub sub factor. A check treatment (weedy) was also included. A rise of herbicide dose, decreased wild oat and foxtail dry weight 35.7 and 12.6 gr/m2, respectively. The results showed that the delay in herbicide application and reduction of herbicide dose decreased grain yield and its components. The highest reduction in grain yield was obtained with 0.6 L/ ha haloxifhope-R-methyl ester herbicide at tillering stage. Application of surfactant caused a decrease in weed dry weight compared to no surfactant and also increased grain yield significantly. In general, to achieve maximum grain yield and the best grass weed control, application of 1 L/ ha haloxifhope-R-methyl ester with surfactant use at 2-leaf in safflower field is recommended.