Orchard had the next highest density of seed bank (42,000 seeds m2). Seed
bank densities accumulated in the top (0-5 cm), middle (5-15 cm),
and lower (15-25 cm) layers of soil were 54%, 23%, and 23%,
respectively (Fig. 3). No moldboard plowing in orchard might
possibly lead to accumulating the seeds within the top soil layers.
Fields with moldboard plow generally had the lowest density in top
soil even though this tool was only used every three years (Colbach
et al., 2014).