Submitted to: North Central Weed Science Society US Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 10, 1998
Publication Date: N/A
Technical Abstract: Smother plants are specialized cover crops developed for their ability to suppress weeds. To compete with early emerging weeds, a successful smother plant must emerge from the soil rapidly, and quickly generate leaf area. Timely establishment presents a fundamental challenge in this system. The objectives for this research were a) to evaluate the emergence dynamics and dground cover of potential smother plant species under a range of crop and environmental conditions, and b) to determine the effects of smother plant growth characteristics on weed suppression and yield of the primary crop. Five species were evaluated: 1) Caliph medic, 2) Santiago medic, 3) Sava medic, 4) Berseem clover, and 5) Short-cycle brassica. The smother plant seed was incorporated within a 25 cm band centered over the corn row at planting time. The corn and smother crop combinations were planted on two dates at Ames and Crawfordsville, IA. Initial smother plant emergence occurred in about 2 weeks for the early planted treatments, whereas the later planted treatments emerged about one week after planting. All species achieved 50% or more ground cover by 72 days after planting (DAP). Brassica had significantly greater percent ground cover than the other species at all observation times, approaching 90% cover at 72 DAP. Weed suppression varied greatly, with Brassica and Sava medic providing significantly greater giant foxtail suppression (60-70%) than Santiago medic (15%). Additionally, Pennsylvania smartweed was suppressed 60-75% by Brassica and Berseem clover.