|Cash, S - MONTANA STATE UNIVERSITY|
Submitted to: Integrated Pest Management Symposium Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 5, 2009
Publication Date: N/A
Technical Abstract: The adoption of zero tillage systems improves soil water conservation, allowing for increased crop intensification and diversification in the semiarid northern Great Plains. Zero tillage systems rely primarily on herbicides for weed management, increasing selection pressure for herbicide resistance. Spring and fall-planted cereals are well adapted to this region and may be suitable herbicide-free forage crops in zero tillage systems. In several trials, we have developed and tested cultural practices for herbicide-free production of annual cereal forage crops, including the influences of planting date, crop entry and population density, nitrogen fertilizer placement, and land rolling. Early planting without preemergence glyphosate in a zero tillage system resulted in excellent forage yields, similar to those from preplant tillage or zero tillage with glyphosate application. Early planting without in-crop herbicide resulted in a small accumulation of weed biomass and no weed seed production. Land rolling after planting approximately doubled densities of tumble mustard, Russian thistle, kochia, and redroot pigweed shortly after crop emergence and at harvest compared to non-rolled; forage harvest of barley occurred prior to any weed seed production. Herbicide application for broadleaf weed control in winter- and spring-seeded cereals did not influence forage yield or water use compared to herbicide-free crops. Combining cultural practices for annual cereal forage crop production can reduce herbicide use and weed seed production.