Weed Management in Rainfed Cropping Systems

Soil water is the most limiting resource to crop production in Nebraska. Much of western Nebraska adopted the summer fallow-winter wheat rotation to deal with this limitation. With herbicides instead of tillage to control weeds and improved management of crop residue, much of western Nebraska has developed more intensive cropping systems. There are four phases in a three-year cropping system involving summer fallow: 1) winter wheat; 2) ecofallow - winter wheat stubble; 3) summer crop (corn, grain sorghum, proso millet or sunflower), and 4) pre-winter wheat fallow. This rotation can decrease problems with winter annual weeds such as downy brome, joined goatgrass, or feral rye. It is the least effective with jointed goatgrass, which as a longer seed life. A single cycle through the rotation usually reduces these weeds but does not eliminate them. This publication covers: Phase I: Controlling broadleaf winter annual in wheat and controlling summer annual broadleaves in wheat; Phase II: controlling weeds in wheat post harvest; Phase III: weed control in the summer crop, including corn, grain sorghum, proso millet and sunflower; Phase IV: Reducing tillage during fallow weed control.