Effects of the herbicide metsulfuron-methyl on root length, nutrient levels, grain protein, and yield of barley

Abstract

In a series of 12 field experiments in 1990 and 1991, metsulfuron-methyl at rates of 2.1, 4.2, and8.4 g/ha (0.5, 1.0, 2.0 times the maximum recommended label rate of the commercial product) was applied at the early tillering stage to commercial barley crops in South Australia.At 4 sites, applications of 4.2 and 8.4 g/ha of metsulfuron-methyl resulted in a marked reduction in plant molybdenum concentrations for at least 6 weeks and grain yield reductions of about 10% resulted from applications of metsulfuron-methyl resulted in a temporary reduction in the concentrations of phosphorus and/or zinc for at least 4 weeks, followed by substantial recovery within 6 weeks. Temporary minor reductions in manganese, copper, sulfur, and potassium concentrations were also measured in the metsulfuron-methyl treatments at 3 sites. At harvest, no nutrient reduction due to chemical treatments was measured in grain samples from any site. Three weeks after the application of 4.2 and 8.4 g/ha of metsulfuron-methyl, marked decreases in total root length were measured in all diameter classes. We suggest these decreases are implicated in the plant these treatments. On these 4 sites and 5 others, nutrient reductions. Applications of metsulfuron-methyl at 4.2 and 8.4 g/ha resulted in grain protein increases of 0.3-0.4%, independent of yield.