Relationship between soil seedbank and field populations of grass weeds in maize

Abstract

The relationship between laboratory enumerations of the weed seedbank and field populations of major grass weeds was studied in several maize fields over a three year period After planting the crop 1 m2 areas were protected from the preemergence herbicide application Soil samples were collected soon after spraying from each area to a depth of 100 mm and the seeds of the major grass weeds enumerated at a seed testing laboratory Emerged weed seedlings were counted in each sampling area over the following 8 weeks Grasses present at these sites included summer grass (Digitaria sanguinalis) smooth witchgrass (Panicum dichotomiflorum) barnyard grass (Echinochloa crusgalli) and rough bristle grass (Setaria verticillata) On average 612 of the seed in the soil seedbank emerged in any one year depending on species Significant linear relationships were established between seed numbers in the soil and the seedlings that emerged in the field