Submitted to: Intnl Conference On Geospatial Information In Agriculture And Forestry
Publication Type: Abstract Only
Publication Acceptance Date: 6/3/2000
Publication Date: 6/3/2000
Citation: Trucco, F., Wyse-Pester, D., Fleming, K., Wiles, L., Westra, P. 2000. Development of organic matter management zones for more efficient application of herbicide. Intnl Conference On Geospatial Information In Agriculture And Forestry. Interpretive Summary: None required
Technical Abstract: Soil pH, organic matter content and structure all influence herbicide efficacy and the averages of these characteristics are used to establish the optimum herbicide rate for a field. With a uniform application, however,herbicide efficacy may vary within a field due to the heterogeneity of soil features and more herbicide than needed may be applied to some areas. It could be beneficial to characterize soil features within a field into management zones for herbicide applications and assign rates so just enough herbicide is used for the desired weed control in each zone. In this study, we determined herbicide management zones based on soil organic matter, applied the recommended rate to each zone and evaluated whether varying rates based on this criterion affected efficacy. A variable rate treatment was applied next to a uniform herbicide application in six strips across two corn fields for two years. Rates of Dual II Magnum plus Atrazine were varied between zones based on organic matter content. The grower slected the uniform herbicide treatment. Weed seedling density was assessed at approximately 100 ft intervals within each strip. Weeds present were pigweed, nightshade and foxtail species, puncturevine, lambs- quarters, kochia and field sandbur. Weed control was very good in both the uniform and variable rate treatments. Efficacy did not vary between rates within the variable treatments; reducing rates based on organic matter did not compromise weed control. Also, weed counts did not differ between the uniform and variable treatments. It may be possible to use maanagement maps based on spatial variation in soil organic matter to vary herbicide rates within a field with no negative effect on weed control.