Weed seed viability is an important parameter to assess the efficacy of soil disinfestation methods like fumigation and steam. In field experiments, seed samples are commonly placed in permeable bags and buried at several depths in soil before the application of soil disinfestation treatments. The seed samples are recovered several days to weeks after treatment and then seed viability is determined in the laboratory. The process of sample installation and recovery is time consuming and may expose personnel to hazardous conditions such as heat or fumigants. Described is a custom soil probe system, developed to simplify installation and recovery of weed seeds from soil. Each soil probe is capable of holding weed seed samples at three different depths up to 30 cm. The following hypothesis was tested: viability of weed seeds is similarly affected by soil disinfestation treatments whether the seeds were contained in the soil probe system or seed bag assays. Two different soil disinfestation trials were conducted: (1) a repeated micro-plot study (USDA Salinas, 1 m-2), using steam as a soil disinfestation treatment and (2) a field study in a commercial strawberry field with 1,3-dicloropropene plus chloropicrin (Pic-Clor 60) as soil disinfestation method. In both studies, seed viability of burning nettle, common knotweed, and common purslane (tetrazolium assay) and germination rates of yellow nutsedge tubers were assessed. Results indicate that the soil probe system can be used as an alternative to the seed bag assay to assess weed control efficacy of described soil disinfestation methods.

A survey was conducted in 2012 across 13 counties in the eastern Arkansas–Mississippi Delta area on 489 randomly selected road sites to assess the distribution of the most commonly occurring arable weeds. Among the 36 species recorded, Palmer amaranth, johnsongrass, large crabgrass, barnyardgrass, prickly sida, and broadleaf signalgrass were the top six weed species, occurring at 313, 294, 261, 238, 176, and 136 sites, respectively. Barnyardgrass, johnsongrass, and Palmer amaranth were present at 34, 32, and 31% of all sampling occasions (site by roadside topographical characteristic). Habitat preferences varied between weed species. Palmer amaranth, large crabgrass, and johnsongrass exhibited a preference for disturbed habitats as well as field shoulders. Conversely, barnyardgrass, yellow nutsedge, hemp sesbania, and giant ragweed exhibit a preference for moist environments similar to these found in roadside ditches. Herbicide use on roadsides is subject to many environmental regulations and public concerns that, in combination with the evolution of herbicide resistance, necessitate an effective plan for managing agronomically important weed species on eastern Arkansas–Mississippi Delta roadsides.