Corn Seed Products Injury Response to Selected Herbicides Under High pH Soil Conditions - DEKALB®

Trial Overview

  • High pH soils are common in Western Kansas and Eastern Colorado.
  • Corn seed products have varying tolerance to high pH soils and these products may have differential injury response to selected growth regulator and HPPD inhibitor herbicides when applied on high pH soil conditions.
 

Research Objective

  • The trial was designed to determine corn seed product injury response to selected herbicides applied early postemergence, when planted in high pH soils.
Location
Soil Type
Previous Crop
Tillage Type
Planting Date
Harvest Date
Potential Yield
Planting Rate
Bethune, CO
Silt loam
Corn
Strip-till
05/08/2017
10/10/2017
240 bu/acre
34,000 seeds/acre

Site Notes:

The trial was planted in two blocks. One block was placed on high pH soils (pH = 8.3) and a check plot was planted on more neutral pH soils (pH = 7.7).The trial was sprayed with each herbicide product, early postemergence, at the maximum labeled rate across the rows at the V2 (two visible leaf collars) growth stage.Plots were evaluated for herbicide injury one week after spray application and rated using the following scale. 
            Warning = plots exhibiting greater than 50% herbicide injury. 
              Caution = plots exhibiting 10 to 49% herbicide injury.
            Good =  plots exhibiting less than 9% herbicide injury.

 

 

Understanding the Results

 
Table 1. DEKALB® brand blend products' injury response to various herbicide active ingredients in high pH (8.3) soil conditions.
 
 
  • No herbicide injury response was observed in near neutral pH (7.7 pH) soil conditions (data not shown).
  • DKC51-38RIB and DKC55-20RIB brand blends were the only corn products that exhibited crop injury to the applied herbicide treatments in high pH soil conditions.
  • DKC51-38RIB brand blend, which is rated as Average for tolerance to high pH soil conditions, exhibited injury from mesotrione/metolachlor/glyphosate herbicide application treatment in high pH soil conditions.
  • DKC55-20RIB brand blend, which is rated as Caution for tolerance to high pH soil conditions, exhibited some injury from tembotrione and isoxaflutole herbicide application and significant injury from mesotrione/metolachlor/glyphosate herbicide application in high pH soil conditions.
 

What Does This Mean for Your Farm

  • Corn seed products rated as Caution for planting in high pH soils generally have a greater risk of exhibiting herbicide injury response from certain HPPD inhibitor and growth regulator herbicides.
  • If high pH soils are a concern, consult your local seed dealer about selecting the appropriate corn seed products that have high pH tolerance and fit your agronomic needs.
  • Use care when selecting herbicide programs for weed control if planting corn seed products with Average or Caution pH tolerance ratings to high pH soil.