Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 10/22/1998
Publication Date: N/A
Technical Abstract: Water use comparisons among fields with different tillage practices have been difficult to achieve. A study was conducted in the Walnut Creek watershed near Ames, Iowa to investigate the effect of different tillage practices and crops on yearly water use. This study was conducted from 1990 through 1996 for three tillage practices, no-till, ridge-till, and chisel-plow, and in both corn and soybean crops. Bowen ratio systems were collected at 30 minute intervals and used to accumulate daily evaporation totals. In the period from early spring until planting, the no-till and ridge-till fields had evaporation rates that were 40-50% less than chisel-plow. Each spring tillage operation increased the evaporation rate up to 12-15 mm over the undisturbed soil. This effect was found in the period after planting until canopy cover. In the fall, the presence of residue decreased evaporation rates. These data have been extended to the watershed to evaluate the effect of cropping systems on seasonal water use patterns.