Consumption of weed seeds and waste grains by seed predators is an important ecosystem service that helps to regulate weed and volunteer crop populations in many agricultural systems. The prairie deer mouse is found in a variety of sparsely vegetated habitats throughout the central United States and is the dominant vertebrate seed predator in row-crop fields (corn and soybean) in this region. Evaluating the preferences of prairie deer mice for common agricultural weed seeds and waste grain is important to understand the potential ability of native mice to regulate volunteer crops and weed populations. We evaluated winter seed preference of deer mice using cafeteria-style feeding trials presented within row-crop fields in central Indiana and used compositional analysis to compare proportional consumption of seeds from five common agricultural weeds (common ragweed, common cocklebur, common lambsquarters, velvetleaf, and giant foxtail) and two grains (corn and soybean) during overnight feeding trials. Prairie deer mice significantly preferred corn to all other available seed types. Ragweed and soybean were also readily consumed and were preferred over seeds other than corn. Giant foxtail was intermediately preferred. Our results show that prairie deer mice have clear preferences for certain seeds commonly available in row-crop fields; mice likely contribute to reduction of waste grain and some weed seed populations.

Knowledge of weed emergence periodicity can inform the timing and choice of weed management tactics. We tested the effects of weed management system (conventional [CNV] and herbicide-free [HF]), timing of rye sowing (two dates), timing of soybean planting (5 planting dates, 3 in each system), and supplemental control (with and without) on weed suppression and weed community composition in soybean no-till planted into a cereal rye cover crop. Cereal rye was terminated with a roller-crimper and herbicide (CNV) or with a roller-crimper alone (HF), and supplemental weed control was achieved with a postemergence glyphosate application (CNV) or with interrow high-residue cultivation (HF). Supplemental control with glyphosate in CNV was more effective than high-residue cultivation in HF. When soybean was planted on the same date, CNV resulted in less weed biomass and a more even community composition, whereas HF resulted in greater weed biomass, dominated by common ragweed. When we controlled for cereal rye biomass and compared the effects of cereal rye sowing and termination timing within each system, earlier management reduced weed biomass in HF, but tended to increase weed biomass in CNV. Our results suggest the ability to control emerged weeds prior to soybean planting is an important factor that influences the optimal cereal rye cover crop management timing for weed suppression.