Postdispersal predation of common lambsquarters (Chenopodium album) and barnyardgrass (Echinochloa crus-galli) seed

Field experiments were conducted from 1995-1997 to determine the influence of tillage and ground cover on the quantity of postdispersal seed predation of common lambsquarters and barnyardgrass. Ground-dwelling invertebrates were the dominant seed predators, and were responsible for 80-90% of all seeds consumed. Predation was highest in no-till and moldboard plowed environments (averaging 32% in both) and lowest in chisel plowed environments (averaging 24%). In no-till, the type of crop residue also influenced the quantity of predation, with highest seed predation found in plots with corn residue (averaging 31%) and lowest in those with soybean and wheat residue (24 and 21%, respectively). It is apparent that there is an optimum combination of residue quantity and quality that maximizes the quantity of seed predation and that other factors such as the mobility of invertebrates and food availability may also play important roles in determining the quantity of seed predation. Seed predators preferred to consume barnyardgrass seed, and for both species, density dependent feeding was evident.