Skip to main content
ARS Home » Midwest Area » Morris, Minnesota » Soil Management Research » Research » Publications at this Location » Publication #96324
Title: TEMPORAL TRENDS IN SPATIAL VARIABILITY OF WEED POPULATIONS IN CONTINUOUS NO-TILL SOYBEAN

Author
item COLBACH, NATHALIE - INRA, FRANCE
item Forcella, Frank
item JOHNSON, GREG - UNIVERSITY OF MINNESOTA

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/8/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Weed populations were monitored from 1993 to 1997 in the same well-managed field at 410 points on a 6.1-m grid system. The major weed species was green foxtail, Setaria viridis. Spatial relationships were analyzed in detail using a geostatistical approach, which included kriging and co-kriging. Of special interest were the spatial relationships of the seedling densities of a given year with those of the following year. This was examined by using cross-semivariograms, which represented the variance between seedling densities of two successive years as a function of the distance between the sampling points. The location and density of foxtail populations in one year could be used to estimate the location and density in the following year with some reliability. However, this reliability decreased substantially after 2, 3, and 4 years. These results indicate that maps of foxtail populations are useful for only one year beyond the year of field mapping. If the decision to apply a herbicide was based on foxtail seedling densities that were estimated to cause a yield loss equivalent to the price of the herbicide applied, then foxtail patches were sufficiently distinct within any one year that only 2 to 40% of the field would have needed treatment with glyphosate (assuming the crop was glyphosate-resistant soybean). Only 0 to 18% of the field would have needed treatment if the herbicide of choice was Imazethepyr.