Submitted to: Weed Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: December 31, 1996
Publication Date: N/A
Technical Abstract: Growers may reduce herbicide use by scouting and by spatially variable herbicide application. The spatial distribution of seedbank and seedling populations must be characterized to optimize these strategies for soil-applied and postemergence herbicide applications. In 8 irrigated corn fields, we sampled seedbank and seedling populations at 1225 sites per field in a 8.1 ha block. Soil cores were collected in the corn row after planting and seedlings were counted in a 5 foot length of corn row 2 to 3 weeks later. Seedling populations consisted of 9 to 23 species in a field and seedbanks consisted of 7 to 19 species. However, just 2 to 6 species made up 90% of the seedbank or seedling population in a field. Spatial distributions were patchy, but the pattern of patchiness varied between fields. Core or quadrat counts were best described with a negative binomial distribution or a logarithmic distribution with zeroes. The proportion of a field free of broadleaf weeds ranged from 1 to 81%. From 11 to 50% of a field was free of grass weeds. Although much less area was sampled with cores than quadrats, maps of seedling and seedbank populations in a field were similar.