Effects of Composted Dairy Cattle Manure and Fresh Dairy Cattle Manure on Seedling Emergence and Seedling Growth of green foxtail (Setaria viridis) and velvetleaf (Abutilon theophrasti) seed

Two separate experiments were conducted in 2014 as a randomized complete block design with four replications to evaluate the effect of application of composted and fresh cow manure on emergence and seedling growth of green foxtail and velvetleaf. Treatments consisted of composted dairy manure at 15, 30, and 60 T/ha, raw dairy manure at 40, 80, and 120 T/ha as well as a control pot, where no manure was added. Investigated traits were seedling emergence, leaf number, leaf area, plant height, plant dry weight and seed number. Results showed that maximum seedling emergence of green foxtail and velvetleaf occurred in nonamended soil (the control). For every measure of amendment with manure retarded growth compared to soil alone or compost-amended mixes. There were not differences in seed production of green foxtail between soil amended with compost and nonamended soil but seed production of velvetleaf was increased in soils amended with compost at 30 T/ha compared to the nonamended soil. Results showed that the differences exist between weed species studied in their response to soil amendments. Depending on the weed species present, use of composted or fresh manure may increase requirements for weed management.