Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 30, 1995
Publication Date: N/A
In steeply sloping farmlands concern that soybean does not produce enough residue to control erosion under conservation tillage has favored production of corn in monoculture, although yields of both crops can be higher when grown in rotation. Previous research at our location has shown that soil and nutrient losses from a corn/soybean rotation were tolerable when a rye cover crop following soybean harvest was used to provide additional residue cover. Runoff from two chiseled and two no-till watersheds was monitored for 4 yr to determine the effect of this rotation on the losses of four herbicides and to compare the behavior of atrazine and linuron. As a percentage of applied chemical, average losses were in the order atrazine (0.39%) > linuron (0.27%) > metribuzin (0.15%) > alachlor (0.06%). Atrazine consistently exceeded 3 ug L**-1 in the first few runoff events after application and was detectable in the runoff during the soybean year. Linuron was rarely detected in runoff following corn harvest or during the soybean year.